Head and neck anat fin


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Head and neck anat fin

  1. 1. Anatomy of head and neck By Amenu Tolera 2010 Tolera, HEAD AND NECK The Skull: anterior, posterior, lateral, superior and inferior views. Interior of the cranium; foramina and what goes via, suture, fontanelles and landmarks. Anterior, middle and posterior cranial fossae. Cervical vertebrae: characteristics of typical and atypical cervical vertebrae. hyoid bone. Comparison of infant and adult skull. 1. Osteology of head and neck The Cranium: A General Overview The Cranium, also called the "Skull," describes the skeleton of the head, face and mandible. It is a portion of the axial skeleton, or that portion associated with the central nervous system. Those portions of the skeleton not associated with the central nervous system, are associated with the appendicular skeleton or the extremities (i.e., the arms and legs). The axial skeleton consists of the cranium, all the osseous elements of the vertebral column, the ribs, and the sternum. In an adult, several of the bones of the cranium are paired left and rights, while others, which cross the mid-sagittal plane, are unpaired. Furthermore, the bones of the skull are classified as those which are called Cranial Bones, or contribute to that portion surrounding the brain, or Facial Bones (i.e., those which do not assist in forming the braincase). The Individual Bones Each of the bones of the cranium posses a number of distinctive features which not only allow the bone to be identified, but also permit its exact location and orientation in the body to be determined (i.e., as a left or right, medial- lateral, posterior-anterior, inferior-superior, etc.). The features listed as characteristic of each of the bones. Page 1 For medical students “au 2nd batch: many many, hard and soft:
  2. 2. Anatomy of head and neck By Amenu Tolera 2010 Tolera, 1. Paired Cranial Bones: Parietals and Temporals 2. Unpaired Cranial Bones:Frontal, Occipital. Sphenoid and Ethmoid 1. Paired Facial Bones: Lacrimals, Nasals, Zygomatics, Maxillae, Palatines and the Inferior Nasal Conchae. 2. Unpaired Facial Bones: Vomer, and Mandible. Exercise: Learn the different views of the skull as shown below. Page 2 For medical students “au 2nd batch: many many, hard and soft:
  3. 3. Anatomy of head and neck By Amenu Tolera 2010 Tolera, Page 3 For medical students “au 2nd batch: many many, hard and soft:
  4. 4. Anatomy of head and neck By Amenu Tolera 2010 Tolera, Page 4 For medical students “au 2nd batch: many many, hard and soft:
  5. 5. Anatomy of head and neck By Amenu Tolera 2010 Tolera, The cranial bones The Frontal Bone The frontal bone may be divided into two main portions, a vertical squamous portion which articulates with the paired parietals along the Coronal Suture and forms the forehead, and two orbital plates, which contribute to the ceiling and lateral walls of the left and right eye orbits. On the external surface the squamous portion frequently possesses a left and right Frontal Eminence. Additionally, the bone possesses two Supra-Orbital Ridges (i.e., Superciliary or Brow Ridges) which are bumps above each of the eye orbits. In early hominids these ridges formed a Torus or large shelf-like process protruding from above the eyes. Associated with each Superior Orbital Margin of the eye orbit the frontal bone may posses a Supra-Orbital Notch or if completely surrounded by bone, a Supra-Orbital Foramen. Above the fronto-nasal suture which allows articulation between the frontal and nasal bones there is generally a trace of the vertical Metopic Suture. In early life the metopic suture divided the frontal bone into left and right halfs. With in the bone, and above and the metopic suture, is the Frontal Sinus. The left and right Frontal Crest, begins at each Zygomatic Process of the frontal bone, and provides the anterior origin of the Temporal Line to which the left and right temporal muscle is attached. Internally, the frontal bone possesses the Median Sagittal (i.e., Sagittal-Frontal) Crest which separates the two frontal hemispheres of the brain. The frontal touches, or articulates with, the following bones: Sphenoid , Parietals Ethmoid , Lacrimals , Nasals , Zygomatics and Maxillae. Test yourself: The incorrect statement is: a. b. c. d. e. Hyoid does not articulate with any other bones Atlas lacks a body and spine Atlas doesn’t posses odontoid process All skull bones doesn’t contain air cells All cervical vertebrae posses bifid spinus process Answer:__________? Page 5 For medical students “au 2nd batch: many many, hard and soft:
  6. 6. Anatomy of head and neck By Amenu Tolera 2010 Tolera, The Parietal Bones The Parietals are paired left and right. Externally, each possess a Superior, and Inferior Temporal Line, to which the temporal muscle is attached. The lines run from the Frontal Crest of the anterior frontal bone to the SupraMastoid Crest on the posterior portion of the temporal bone. The parietals articulate with each other by way of the Mid-Sagittal Suture, and with the frontal bone anteriorly by way of the Coronal Suture. These two sutures generally form a right angle with one another. Posteriorly, the parietals articulate with the Occipital Bone by way of the Lambdoid Suture. The intersection of the Lambdoid and Sagittal Sutures approximate a 120 degree angle on each of the parietals and the occipital bone. Among the sutures the Lambdoid is by far more serrated than either the Sagittal or the Coronal. Inferiorly the Parietal articulates with the temporal bone by way of the Squamosal and Parieto-Mastoid Sutures. On the external surface near the center of the bone is the Parietal Eminence. Slightly posterior to the eminence there may be a Parietal Foramen. Internally, the bones possess a number of Meningeal Groves as well as perhaps some number of Arachnoid Foveae. The groves generally branch from the inferior/anterior edge of the bone to superior/posterior, while the foveae are frequenly found along the sagittal suture. At the area of intersection of the lambdoid and parieto-mastoid sutures there is a brief portion of the Sigmoid (i.e., Transverse) Sulcus. The parietals touch, or articulate with, the following bones: Occipital , Frontal , Temporal , Sphenoid and Parietals. Test yourself: sella turcica belong to which cranial bone? Answer:_________________? Page 6 For medical students “au 2nd batch: many many, hard and soft:
  7. 7. Anatomy of head and neck By Amenu Tolera 2010 Tolera, The Occipital Bone The Occipital Bone consists of a large squamous, or flattened portion separated from a small thick basal portion by the Foramen Magnum on either side of which is a left or right Occipital Condyle. The occipital condyles articulate with the first cervical vertebrae (the Atlas). Externally, the squamous portion of the bone possesses Superior, Middle, and Inferior Nuchal Lines to which the muscles at the back of the neck are attached. The External Occipital Protuberance lies on the superior nuchal line in the mid-sagittal plain. Lateral to each occipital condyle are the Condylar Fossae and Foramen while the Hypoglossal Canal is medial to them. Internally, are the Sagittal and Transverse Sulci, or grooves which converge at the Confluence of Sinuses. A single internal Occipital Protuberance or Cruciform Eminence is also found in this area. Running inferior from the eminence to the foramen magnum is the Internal Occipital Crest which separates the Cerebellar Fossae. The transverse sulci assist in directing the developing jugular vein to the Jugular Notch on either side of the basilar portion of the occipital. The occipital touches, or articulates with, the following bones: Parietals , Temporals , Sphenoid and Atlas. The atlas is not part of the skull. It is the first of the seven cervical vertebrae and the one upon which the base of the skull sits. It is the bone around which the skull rotates, hence the name "atlas." The Temporal Page 7 For medical students “au 2nd batch: many many, hard and soft:
  8. 8. Anatomy of head and neck By Amenu Tolera 2010 Tolera, The Temporal Bone is another paired cranial bone which is difficult to describe due to its various features, and projections. It consists of two major portions, the Squamous Portion, which is flat or fan-like and projects superiorly from the other, very thick and rugged portion, the Petrosal Portion. The squamous portion assists in forming the Squamous Suture which separates the temporal bone from the adjacent and partially underlaying parietal bone. The petrosal portion contains the cavity of the middle ear and all the ear ossicles; the Malleus, Incas and Stapes. This portion projects anterior and medialy beneath the skull. Projecting inferiorly from the petrosal portion is the slender Styloid Process which is of variable length. The styloid process serves as a muscle attachment for various thin muscles to the tongue and other structures in the throat. Externaly the petrosal portion possesses the External Auditory Meatus while internally there is an Internal Auditory Meatus. Anterior to the external meatus the Zygomatic Process has its origin. This process projects forward toward the face and its articulation with the temporal process of the zygomatic. Just anterior of the external meatus and inferior of the origin of the zygomatic process is the Glenoid or Mandibular Fossa which assists in forming the shallow socket of the Tempro-Mandibular Joint. Posterior to the external auditory meatus is the inferiorly projecting Mastoid Process which serves as an attachment for the sternocleidomasotid muscle. Above the mastoid process is the Supramastoid Crest to which the posterior portion of the temporal muscle is attached. The temporals touch, or articulate with, the following bones: Occipital , Sphenoid Parietals , Zygomatics and Mandible . The Sphenoid The Sphenoid is one of the more difficult bones to describe and in vision. It has a number of features and projections, which allow it to be seen from various views of the skull. It is a single bone that runs through the midsagittal plane and aids to connect the cranial skeleton to the facial skeleton. It consists of a hollow body, which contains the Sphenoidal Sinus, and three pairs of projections: the more superior Lesser Wings, the intermediate Greater Wings, and the most inferior projecting Pterygoid Processes. Internally upon the body is the Sella Turcica where the pituitary gland rests in life. The smaller lesser wings posssesses the Optic Foramen through which the optic or second cranial nerve passes before giving rise to the eye. The Supra-Orbital Fissure separates the lesser wing superiorly from the greater wing below and can best be viewed on the posterior wall of each eye orbit. The left and right greater wings assist in forming the posterior wall of each of the eye orbits where it forms an Orbital Plate. In addition the external surface of the greater wing can be viewed in the lateral view of the cranium in an area called the Pterion Region. Just inferior to the supra-orbital fissure near the body of the sphenoid, each of the greater wings also possess a Foramen Rotundum which in life transmits the maxillary branch of the fifth, or trigeminal, cranial nerve. Each of these wings also possesses a much larger Foramen Ovale more laterally, which transmits the mandibular branch of the same nerve. More posteriorly is the smallest of the three pairs of foramena, the Foramen Spinosum which transmits the middle meningial vessels and nerve to the tissues covering the brain. Page 8 For medical students “au 2nd batch: many many, hard and soft:
  9. 9. Anatomy of head and neck By Amenu Tolera 2010 Tolera, The left and right pterygoid processes project inferiorly from near the junction of each of the greater wings with the body of the sphenoid. These processes run along the posterior portion of the nasal passage toward the palate. Each process is formed from a Medial and Lateral Pterygoid Plate to which the respective medial and lateral pterygoid muscle is attached during life. The muscles run from these attachments to the internal, or medial surface, of the mandible in the area of the gonial angle. In life the muscles assist in creating the grinding motion associated with chewing. The sphenoid touches, or articulates with, the following bones: Vomer , Ethmoid , Frontal , Occipital , Parietals , Temporals , Zygomatics and Palatines . The Ethmoid If the sphenoid is the most difficult cranial bone to describe and in vision, the Ethmoid is the second most difficult. It has a number of features and projections, but unlike the sphenoid it cannot be seen from various views of the skull. Like the sphenoid, it is a single bone that runs through the mid-sagittal plane and aids to connect the cranial skeleton to the facial skeleton. It consists of various plates and paired projections. The most superior projection is the Crista Galli, or Cocks Comb, found within the cranium. It assists in dividing the left and right frontal lobes of the brain. Lateral projections from the Crista Galli are the left and right Cribriform Plates which in life cradle the first cranial nerves i.e., the olfactory nerves. The nerves brachiate through the porosity of these plates into the nasal cavity below. Directly inferior to the Crista Galli and running in the mid-sagittal plane is the Perpendicular Plate of the ethmoid which articulates with the vomer more inferiorly and assists in separating the left and right nasal passages. The Perpendicular Plate can be viewed anteriorly through the nasal cavity. Descending off each of the Cribriform Plates is a left or right Orbital Plate which aids to form the medial wall of the respective eye orbit. Each Orbital Plate is rectangular in shape and gives rise to two medial projections, the Superior and Middle Nasal Concha. These projections, like the separate Inferior Nasal Concha, assist in increasing the surface area within the nasal cavity and thereby the exposure of the brachiating olfactory nerve to inhaled odors. The Superor or Supreme Nasal Conche are smaller, and cannot be viewed through the anterior nasal opening because it is blocked from view by the the more inferior Middle Nasal Conche. The ethmoid touches, or articulates with, the following bones: Sphenoid , Frontal Maxillae , Palatines , Vomer and Lacrimals. Page 9 For medical students “au 2nd batch: many many, hard and soft:
  10. 10. Anatomy of head and neck By Amenu Tolera 2010 Tolera, Facial bones The Nasal Bones Each of the nasal bones is a small rectangular bone which together form the bridge of the nose above the Nasal Cavity also called the Piriform Aperture. They articulate with each other by way of the Internasal Suture and with the frontal bone superiorly by way of the Fronto-Nasal Suture just below the glabellar region of the frontal bone. The intersection of these two sutures marks the anatomical landmark called Nasion. Laterally, each of the nasal bones articulates with the frontal process of the maxilla. A nasal touches, or articulates, the following bones: Frontal , Maxilla and Nasal The Maxillae The Maxillae are the paired facial bones which contain the upper dention and thus form the upper jaw. Each is basicly hollow with a large Maxillary Sinus. A superior projection, the Frontal Process, assists in forming the lateral margin of the nasal aperture and ends by articulating with the frontal bone. An Orbital Plate forms the floor of the eye orbit, while the Zygomatic Process articuates with the zygomatic bone. On the anteror surface of the bone, near the maxillo-zygomatic suture, ther is an Infra-Orbital Foramen. The Alveolar Process of the Maxilla contains the upper dentition and assists in giving rise to the Palatine Portion which forms the anterior half of the hard palate. The left and right Maxillae articulate with one another by way of the Inter-Maxillary Suture. The superior end of this suture frequently terminates with the Nasal Spine. A maxilla touches, or articulates with, the following bones: Frontal , Ethmoid , Zygomatic , Vomer , Lacrimal , Maxilla , Nasal , Palatine , Mandible and Inferior Nasal Concha . Page 10 For medical students “au 2nd batch: many many, hard and soft:
  11. 11. Anatomy of head and neck By Amenu Tolera 2010 Tolera, The Zygomatic Bones Also called the Malars or Jugals, each cheek or zygomatic bone possesses three major processes which articulate with the bones which surround it. The Frontal Process of the zygomatic forms the lateral margin and wall of the eye orbit and projects superiorly to articulate with the zygomatic process of the frontal bone. This portion of the bone separates the eye orbit from the temporal fossa and possesses a posterior projecting edge called the Marginal Process. The Temporal Process of the zygomatic runs lateral and posterior toward an articulation with the zygomatic process of the temporal bone. Together these two processes assist in forming the zygomatic arch which serves as the attachment for the masseter muscle in life, one of the primary muscles used in mastication. The temporal muscle runs beneath the arch and is also a primary mover of the mandible in chewing. The Maxillary Process of the zygomatic articulates with the zygomatic portion of the maxilla by way of the Zygo-Maxillary Suture. The zygomatics touch, or articulate with, the following bones: Frontal , Sphenoid , Maxillae and Temporals. Page 11 For medical students “au 2nd batch: many many, hard and soft:
  12. 12. Anatomy of head and neck By Amenu Tolera 2010 Tolera, The Vomer Bone The Vomer is a single relatively flat bone located in the mid-sagittal plane. It articulates with the perpendicular plate of the ethmoid superiorly and together aid in forming the nasal septum. While it is frequently deflected slightly to the left or right, in general the septum is aligned perpendicularly and divides the the nasal aperture into the the left and right nasal passages. In addition to the Perpendicular Portion, superiorly the Vomer mushrooms out into a pair of Alae which terminate and articulate with the sphenoid in a heart shaped process. Inferiorly the Vomer rests on both the maxillae and the palatines. The vomer touches, or articulates with, the following bones: Sphenoid , Ethmoid Palatines and Maxillae . The Palatine Bones The Palatine Bones are paired left and right and articulate with one another in the mid-sagittal plane at the Interpalatine Suture. Both bones assist in forming the posterior portion of the hard palate as well as a portion of the nasal cavity. Each bone possesses a Horizontal Part, with an inferior surface which forms the posterior portion of the hard palate and a superior surface that assists in forming the posterior portion of the floor of the nasal cavity. The Vertical Part of each contributes to the lateral wall of the nasal cavity. Near the posterior junction of the Vertical and Horizontal Parts on the palatal surface is a Palatine Foramen. Each bone possesses a number of processes and articular surfaces which touch the bones that surround it. A palatine touches, or articulates with, the following bones: Sphenoid , Ethmoid , Maxilla , Vomer and Palatine. Page 12 For medical students “au 2nd batch: many many, hard and soft:
  13. 13. Anatomy of head and neck By Amenu Tolera 2010 Tolera, The Inferior Nasal Concha The Inferior Nasal Concha is a very thin, porous, and fragile, paired bone basically elongated and curled upon itself. It lays in the horizontal plane and is attached to the lateral wall of the nasal cavity. By way of the Maxillary Process on the bone's lateral surface, it is attached to the maxilla, and by way of the Lacrimal, Ethmoid and Palatine Processes to each of the bones which assist in forming the lateral wall of the nasal cavity. By projecting into the nasal cavity, the medial surface of the Inferior Nasal Concha assists in increasing the surface area within the cavity and thus increases the amount of mucus membrane and olfactory nerve endings exposed to inhaled odors. An inferior nasal concha touchs, or articulates with, the following bones: Ethmoid , Lacrimal , Maxilla Palatine . The Mandible The Mandible or lower jaw consists to four major portions, a left and right Mandibular Ramus and the left and right Body. The Alveolar Process of the body is that portion of the mandible which contains the lower dentition. The junction of the ramus and the body occurs at the Gonial Angle where externally one of the masseter muscles is Page 13 For medical students “au 2nd batch: many many, hard and soft:
  14. 14. Anatomy of head and neck By Amenu Tolera 2010 Tolera, attatched. The left and right masseters make up a set of two sets of muscels used in chewing. At the gonial angle on the internal surface the Pterygoid Attachements are found. These attachements are for the medial and lateral pterygoid muscles which assist in the grinding motion of chewing. The external surface of the mandibular body possesses the Mental Foramen and at the midline, the Mental Protuberance or chin. The internal surface of the body possesses the Lingual Foramen, the Mandibular Canal, and the longitudinal running Mylo-Hyoid Ridge. The Genio Tubercle is located in the mid-sagittal plane on the internal surface of the mandible. The superior margin of each ramus possesses both a Mandibular Condyle or Head, for articulaltion with the temporal bone at the tempro-mandibular joint, and the Coronoid Process, for the attachement of the temporalis muscle (one in the set of primary muscles used in mastication). The mandible articulates with each of the Maxillae by way of their contained respective lower and upper dentition. The mandible touches, or articulates with, the following bones: Temporals and Maxillae. The Hyoid Bone The hyoid is a single small "U" shaped bone in the adult which does not articulate with any other bone. It is suspended from the styloid process of each temporal bone by means of the stylohyoid ligaments. It is located in the mid-sagittal plane, at the front of the throat, and beneath the mandible but above the larynx near the level of the third cervical vertebrae. It is formed from three separate parts (i.e., the Body, and the left and right Greater and Lesser Cornu) which fuse in early adulthood. The base of the "U" shaped bone is located anteriorly while the Cornu project posteriorly Cervical vertebrae Are five typical or three atypical. The typical cervical vertebrae are 3rd to 6th , has a body, vertebral foramen and vertebral arch with pedicle, lamina, superior and inferior articular facets,trnaseverse process with foramen transvesarium and spine. The atypical vertebrae are the 1st or atlas , the 2nd or axis and the 7th or verebra prominens. The cervical vertebrae are easily distinguished because their spinus process is short and bifid, and the foramen transeversarium from 6th to 1st transmit the vertebral artery and its sympathetic plexus and the vertebral veins. The atlas is atypical because its lacks body and has two lateral masses.the superior articular faces on on the lateral masses are kidney shaped and articulates with occipital condyles of the skull to form atlantocipital joints. This joint allows flexion and extension or nodding movements. The inferior articular facet on the lateral masses form Page 14 For medical students “au 2nd batch: many many, hard and soft:
  15. 15. Anatomy of head and neck By Amenu Tolera 2010 Tolera, the atlantoaxial joints and This joint allow side or rotatory movements. That is we move our head saying yes by atlantocipital and no by atlantoaxial joint.It also has anterior and posterior tubercles, articular facet for dens and groove for 3rd part of vertebral artery. Axis is atypical because it has a tooth like odontoid process or dens. The vertebra prominens is so because it has long spinus process which is not bifid. NO 1 2 3 4 Name of the foramen In anterior cranial fossa Cribriform foramina Foramen cecum Anterior ethmoidal foramina Posterior ethmoidal foamina Middle cranial fossa Structures which go through it Olifactory nerves Occussional emissary veins from nasal mucosa to superior saggital sinus Anterior ethimidal VAN Posterior ethmoidal VAN Page 15 For medical students “au 2nd batch: many many, hard and soft:
  16. 16. Anatomy of head and neck 5 Optic canal 6 Superior orbital fissure 7 8 Foramen rotundum Foramen ovale 9 Foramen spinosum 10 Foramen lacerum 11 Carotid canal 12 Posterior cranial fossa Internal acoustic meatus 13 Jugular foramen 14 Hypoglossal canal 15 Foramen magnum 16 17 Condyloid foramen Mastoid foramen By Amenu Tolera 2010 Tolera, 1. 2. 3. 1. Optic nerve with its meningeal sheath Ophthalmic artery Central vein of the retina Occulomotor,trochlear, ophthalmic branch of trigeminal ,abducent nerves 2. ophthalmic veins, 3. meningeal branch of lacrimal artery 4. sympathetic nerves from plexus around ICA. Maxillary branch of trigeminal nerve 1. Mandibular branch of trigeminal nerve 2. accessory meningeal artery 3. lesser petrosal nerve occasionally 4. emissary veins connecting cavernous sinus with pterygoid plexus of veins 1. Middle meningeal artery 2. Meningeal branch of mandibular nerve or nervous spinosum 3. Posterior trunk of middle meningeal vein 1. Meningeal branch of ascending pharyngeal artery 2. Emissary veins from cavernous sinus 1. ICA 2. Venous and symphatetic plexus around ICA 1. 2. 3. 1. Facial nerve Vestibulocochlear nerve Labrynine artery Inferior petrosal sinus and meningeal branch of ascending pharyngeal artery in the anterior part 2. IJV and meningeal branch of occipital artery in the posterior part 3. Glossopharyngeal,vagus abd accessory nerves in the middle part 1. Hypoglossal nerve 2. Meningeal branch of asending pharyngeal artery 3. Emissary veins 1. Spinal cord with its meninges 2. Spinalaccessory 3. Vertebral arteries 4. Sympathetic plexus around vertebral artery 5. Venous plexus of vertebral canal 6. Anterior and posterior spinal arteries Condyloid emissary veins Meningeal branch of occipital artery Mastoid emissary vein In base of skull Page 16 For medical students “au 2nd batch: many many, hard and soft:
  17. 17. Anatomy of head and neck 18 Sylomastoid foramen 19 20 Pterygotympanic fissure Incisive foramen 21 22 Greater palatine foramen Lesser palatine foramen In front of the skull Zygomaticofacial foramen Supraorbital foramen Inferior orbital fissure 23 24 25 26 27 28 29 30 Infraorbital foramen Mental foramen Nasolacrimal canal Mandibular foramen In the calvaria Parietal foramen By Amenu Tolera 2010 Tolera, 1. Exit of facial nerve fro facial canal 2. Stylomastoid branch of posterior auricular artery Chorda tympani of facial nerve 1. Terminal part of greater palatine vessels from palate to nose 2. Terminal part of nasopaltine nerve from nose to palate Greater palatine VAN Lesser palatine VAN Zygomaticofacial VAN Supraorbital and trochlear VAN 1. Zygomatic nerve 2. Orbital branch of pterygopalatine ganglion 3. Connecting veins between inferior ophthalmic veins and pterygoid plexus of veins Infraorbital VAN Mental VAN Nasolacrimal duct Inferior alveolar VAN Parietal emissary veins from superior saggital sinus to occipital veins 3. Arthrology of head and neck The joints of head and neck are either fibrous or synovial types. They include the sutures, atlantoccipial, atlanoaxial, intervertebral , tempromandibular joints and the joints between auditory ossicles. Just like elsewhere, this joints are reinforced by ligaments. The ligaments which stabilize the cervical vertebrae includes anterior and posterior longitudinal, ligamentum flavum, posterior and anterior altantoocipital membrane, transe verse, and cruciate ligaments. The scalp and face The scalp Scalp is region of head which extends from inion posteriorly to eye brows anterirly and each side of superior temporal lines laterally. The skin of the scalp continues from t he front and lateral side of the face into the occipital region of the skull posteriorly. The makeup of the scalp is important clinically because trauma to the scalp is frequent and it is up to the clinician to determine by palpation and observation just how serious the trauma is. Layers of scalp. The scalp is made of 5 layers and they spell scalp: from outer to inner are. Page 17 For medical students “au 2nd batch: many many, hard and soft:
  18. 18. Anatomy of head and neck By Amenu Tolera 2010 Tolera, S – skin is with hairs and glands C -- dense Connective tissue is the superficial fascia A – aponeurosis or galea aponeurotica is the membraneous tendon of fleshy bellies of occipicto frontalis muscle 4. L -- loose connective tissue is the danger area of the scalp P -- periosteum or pericranium is the outer coverning of the bone. 1. 2. 3. The 1st three layers of the scalp are firmly attached to each other with the dense fibrous tissue hence in most dissection they are pulled together and commony called scalp proper. Page 18 For medical students “au 2nd batch: many many, hard and soft:
  19. 19. Anatomy of head and neck By Amenu Tolera 2010 Tolera, Muscles of the scalp. It is made up of a single muscle occipitofrontalis with two bellies. The occipital belly arises from occipital bone and insert into epicranial aponeurois. The frontal belly arises from frontal bone and also insert into epicranial aponeurosis. Innervation is posterior auricular branch and temporal branch of facial nerve respectively. Their action is to produce the horizontal wrinkles seen posteriorly and anteriorly on fore head. Neurovascular bundle of scalp and Temple NERVE SUPPLY. The scalp has two motor and eight sensory nerves which are distributed in the in front and behind of the auricle. Hence ten nerves are distributed to the scalp making it more sensitive. no a 1 Nerves In front of auricle Sensory nerves Supratrochlear from V1 2 Supraorbital from V1 Zygomaticotemoral from V2 Auriculotemporal from V3 Motor nerve Temporal branch of VII 4 5 Nerves Behind auricle Sensory nerves Posterior division of greater auricular, C2 and C3 from cervical plexux Lesser occipital, C2,C3 Greater occipital, C2 from dorsal ramus 3rd occipital C3, from dorsal ramus Motor nerve Posterior auricular branch of VII BLOOD SUPPLY. Five arteries three in front and two behind the auricle supply the scalp. These arteries form rich anastomosis. no Arteries Source from a. in front of auricle 1 supratrochlear Optlamic artery which comes from ICA 2 Supra orbital Optlamic artery which comes from ICA 3 Superficial temporal ECA b. Behind auricle 4 Posterior auricular ECA 5 occipital ECA VENOUS DRAINAGE. The veins accompanying the arteries will drain as follows. 1. supratrochlear and supraorbital will unite and form anglar vein which becomes the anterior facial vein. 2. superficial temporal vein unite posterior auricular vein and forms posterior facial vein which is also called retromandibular vein. 3. occipital veins drain into occipital venous plexus. Lymphatic drainage. The scalp is devoid of lymph nodes but lymphatics from the scalp will drain into five neighboring lymph nodes of the face. lymphatics infront of the auricle drain into submental, submandibular and parotid group of lymph nodes respectively from medial to lateral. Lymphatics behind the auricle drain into mastoid and occipital groups of lymph nodes respectively. Clinical anatomy Problem of Gaping of scalp. The blood vessels travel through the dense connective. The connective tissue has a special relationship with the arteries in this area. When an artery is severed, the connective tissue fibers around the vessel contract and pull the artery open. This Page 19 For medical students “au 2nd batch: many many, hard and soft:
  20. 20. Anatomy of head and neck By Amenu Tolera 2010 Tolera, result is more hemorrhage than in other places. With scalp hemorrhage, compression must be used to stop the bleeding. High bleeding Blood vessels and nerves come into the scalp from three different regions: 1) anterior (supraorbital), 2) lateral (superficial temporal), 3) posterior (occipital). There is free anastomoses from side to side. With all of this blood supply, lacerations of the scalp are usually profuse and because of the nerve supply, very sensitive. Black eye and the Danger area of scalp. The loose connective layer of the scalp will allow bacteria or fluid to pass freely from the posterior aspect of the scalp into the eyelids in front causing black eye. Trauma in the back of the head can result in blood showing up in the eyelids and should make you suspect something going on in the back of the head. Infection in this area will also distribute to intracranial structures like the brain via parietal emissary veins, which are valueless veins. They connect the scalp with interior like cavernous sinus passing via parietal foramina of the skull. In brief, Emissary veins (valveless) may spread infections from the scalp to the intracranial cavity. Normal blood flow is from inside to outside of the skull. The face Definition. Anterior aspect of the head from the forehead to the chin vertically, and from one ear to the other ear horizontally. The Skin. Has four basic features 1. Is highly vascular, hence wounds of face bleed profusely but heal rapidly and plastic surgery is excellent on face 2. Is highly elastic and thick 3. Is rich in sebaceous and sweat glands 4. Act as attachment or insertion for muscles of facial expression Fascia.. The superficial fascia contains muscles of facial expression, fat and neurovascular bundles. No deep fascia except over parotid gland. Facial musculature. Two main groups of muscle are located on the face: muscles of facial expression innervated by the facial nerve (cranial nerve VII) because they are derived from the 2nd pharyngeal arch, and muscles of mastication supplied by the mandibular division of the trigeminal nerve (cranial nerve V) because they are derived from the 1st pharyngeal arch. Muscles of facial expression (innervated by the facial nerve) are superficial muscles which can move skin and fascia in various directions. They are also dilators and sphincters for the various orifices in the face region. The 2 major groups are around the eye and the mouth. Around the eye: The sphincter is the orbicularis oculi which has: a palpebral part in the eye lid (closes eye gently) and an orbital part which surrounds the orbit and blends in with the anterior belly of occipitofrontalis (closing the eye forcibly). The orbital part causes radiating skin wrinkles from the lateral corner of the eye.The dilator is the levator palpebrae superioris, innervated by the oculomotor nerve (cranial nerve III) and postganglionic sympathetic fibers from the superior cervical ganglion. Around the mouth: The sphincter is the orbicularis oris , which closes the lips but can also protrude the lips as in whistling, or kissing.The dilators are: Levator labii superioris alaeque nasi , Levator labii superioris , Levator anguli oris , Zygomaticus minor , Zygomaticus major , Platysma , Depressor anguli oris , Depressor labii inferioris and Mentalis. The buccinator is the main Page 20 For medical students “au 2nd batch: many many, hard and soft:
  21. 21. Anatomy of head and neck By Amenu Tolera 2010 Tolera, muscle of the cheek and it keeps the cheeks in contact with the gums so that food does not accumulate in the vestibule of the mouth. Neurovascular bundles of the face The sensory nerves of the face are the 11 terminal branches of the three divisions of the trigeminal nerve (cranial nerve V). Motor are facial for all muscles of facial expression and Motor branches of V3. no nerves Nature and distribution a Sensory nerves from V1 Is purely sensory 1 supratrochlear All are distributed to 2 3 supraorbital Lacrimal The area of the face developed 4 infratrochlear From frontonasal eminence from anterior to posterior " 5 external nasal " 6 7 8 Maxillary division (V2) zygomaticotemporal zygomaticofacial infraorbital Mandibular division (V3) Is purely sensory All are distributed area of the face derived from maxillay eminence from posterior to anterior auriculotemporal bucal mental Motor nerve Facial with five branches Temporal branch Zygomatic branch Bucal branch Mandibular branch Cervical branch trigeminal All are distributed area of the face derived from mandibular eminence from posterior to anterior 9 10 11 12 a b C d e 13 Is mixed terminal All mm. of facial expression Occipitofrontalis and etc. Zygomaticus and etc. Baccinator and etc. Mentalis,derpssor labi inferoris etc. Platysma in the neck All mm. of mastication Blood supply. The face gets blood supply from two major sources . Ophthalmic arteries from ICA give supraorbital and supratrochlear arteries. Facial artery and superficial temporal arteries from ECA will also supply the face via their branches. The facial artery: provides the main blood supply. passes over the lower border of mandible at the anterior border of the masseter (feel the pulse). has a tortuous course to allow for movement of the face, first to the angle of the mouth and then up at the side of the nose to the medial angle Page 21 For medical students “au 2nd batch: many many, hard and soft:
  22. 22. Anatomy of head and neck By Amenu Tolera 2010 Tolera, of the eye. gives off upper and lower labial branches as well as numerous other branches to the face. Free anastomoses on the same side as well as across the midline The superficial temporal artery is a smaller terminal branch of the external carotid artery. Its pulse can be felt in front of the tragus of the ear. Above the ear it divides into anterior and posterior branches. It anastomoses with the facial artery. The facial vein has a straighter path and communicates with deeper veins such as veins of the orbit (leading to the cavernous sinus within the skull; at the medial angle of the eye and the pterygoid venous plexus. The central face area is thus a "danger area" for an infection on the face to travel into the skull or into the deep face. The retromandibular vein is formed in the parotid gland by the union of the maxillary and superficial temporal veins, emerges from the gland near the angle of the mandible divides into twowith the anterior branch or division joining the facial vein and draining into the internal jugular vein, the posterior branch or division joins with the small posterior auricular vein to form the external jugular vein. Lymphatic drainage. Lymphatic from the the five groups of lymph nodes drain into superficial or deep cervical groups of lymph nodes. Clinical anatomy Bell's Palsy: Lesions of the facial nerve (Cranial nerve VII). Drainage of tears and dribbling of saliva due to paralysis of the two main orbicularis muscles. Paralysis of buccinator will lead to accumulation of food in the vestibule. Test by asking patients to screw up the eye (loss of muscle tone causes the normal skin folds to disappear on the side of the lesion), to smile or to whistle. Muscles must be supported during recovery or they will stretch under gravity and cause a permanent asymmetry of the face. Unilateral facial muscles paralysis Test: 1) For loss of taste in the anterior 2/3 of tongue for the integrity of the chorda tympani. 2) For hyperacusis to test the integrity of the nerve to stapedius. 3) For lack of lacrimation on one side for the integrity of the greater (superficial) petrosal nerve. If this is present, it will result in dessication of cornea, ulceration and blindness. Dessication of cornea will result in pain sensation carried by V1.If all 3 signs are present then the lesion is between the brainstem and the geniculate ganglion. Bell's palsy usually affects only branches of the facial nerve (VII) below the stylomastoid foramen. Danger area or triangle of the face. The facial vein is important clinically because it has a direct connection to the ophthalmic vein and then to a deep venous sinus within the cranial cavity, the cavernous sinus causing thromboplebitis of it. Bacteria or infectious agents can enter the facial vein and gain access to internal cranial structures resulting in infection there. This is probably the reason why our mothers always said not to squeeze our pimples. The lacrimal apparatus is an apparatus which drains tears from the galand to inferior meatus of the nose. It is made up of 1. 2. 3. 4. The lacrimal gland and its ducts conjectival sac lacrimal punctum and lacrimal canaliculi lacrimal sac Page 22 For medical students “au 2nd batch: many many, hard and soft:
  23. 23. Anatomy of head and neck By Amenu Tolera 2010 Tolera, 5. nasolacrimal duct Blood supply. is from ophthalmic artery Venous drainge. ophthalmic veins Nerve supply. lacrimal nerve This nerve has both sensory and secretomotor fibers. Secretomotor fibers begin in lacrimatory nuclus of CNVII . See pterygopalatine ganglion. Facial nerve. Is the 7th cranial nerve which arises as four nuclei in the brain stem from 1. 2. 3. 4. the motor muscles which is branchiomotor the superior salivatory nucleus which is parasympathetic lacrimatory nucleus which is also parasympathetic nucleus of tractus solitarius which is gustatory This nerve enters the internal acoustic meatus and goes via facial canal by forminging geniculate ganglion via strylomastoid formaen. It gives three branches in the facial canal these are the greater petrosal, nerve tostapedius and chordatympani. It gives also gives three branches as just it exit from stylomastoid foramen,these are posterior auricular nerve to occipitalis, nerve to sytlohyoid and posterior belly of digastric. It finally gives five terminal glands in the substance of the parotid gland. These are top to bottom are temoral, zygomatic, buccal, mandibular and cervical. THE TEMPORAL AND INFRATEMPORAL REGIONS Temporal fossa : Lies on the side of the skull between temporal lines and zygomatic arch. It is continuous with infratemporal fossa below the arch. The INFRATEMPORAL TEMPORAL FOSSA Lies Inferior to the temporal fossa and zygomatic arch and deep to the ramus of the mandible. It stretches from the parotid fascia posterior to the mandibular ramus to the tuberosity of the maxilla. Walls. The lateral wall is formed by the medial aspect of ramus of the mandible. The anterior wall is formed by the: Body and tuberosity of the maxilla, deep to zygoma and zygomatic process of the maxilla. The pterygomaxillary fissure may be seen in the medial aspect of this anterior wall, opening into the more medial pterygopalatine fossa. The inferior orbital fissure may also be seen. Inferior to the pterygomaxillary fissure is the hamulus serving as attachment point for the pterygomandibular raphé. It serves as the common site of origin for the buccinator and the superior constrictor muscle and runs from the hamulus to the upper 1/5 of the mylohyoid line. The medial wall is formed by the: lateral pterygoid plate, superior constrictor muscle, levator and tensor palati muscles. Page 23 For medical students “au 2nd batch: many many, hard and soft:
  24. 24. Anatomy of head and neck By Amenu Tolera 2010 Tolera, The roof of the infratemporal fossa is formed by: the greater wing of the sphenoid anteriorly and the squamous portion of the temporal bone posteriorly. The infratemporal crest is on the anterior aspect of the undersurface of the greater wing of the sphenoid and serves as an attachment site for the upper head of the lateral pterygoid. Posterior to this infratemporal crest are:The foramen ovale for transmission of V3 and the lesser petrosal nerve (from IXth) from the middle cranial fossa to the infratemporal fossa. The foramen spinosum for transmission of the middle meningeal artery from the infratemporal fossa to the middle cranial fossa. Contents of the infratemporal fossa 1. Four Muscles of Mastication Action Nerve Supply closes mouth muscular branch (V3) Muscle Origin Insertion masseter zygomatic arch ramus & mandible medial pterygoid medial surface of lateral medial surface of closes mouth and helps muscular pterygoid plate and maxillary ramus and angle of protrude mandible branch (V3) tuberosity mandible lateral pterygoid upper head: greater wing of upper head: articular open and protrudes sphenoid disc muscular mandible, moves mandible lower head: lateral surface of lower head: neck of branch (V3) side to side lateral pterygoid plate condyle angle of Page 24 For medical students “au 2nd batch: many many, hard and soft:
  25. 25. Anatomy of head and neck temporalis temporal fossa By Amenu Tolera 2010 Tolera, coronoid process and muscular anterior border of closes and retracts mandible branch ramus Note. All muscles of mastication are innervated by mandibular division of trigeminal nerve, why? 2. Maxillary artery and its branches The maxillary artery lies lateral to the lateral pterygoid muscle. Arise from from the external carotid artery as a larger terminal branch in the parotid gland, the artery enters the posterior aspect of the infratemporal fossa by passing deep to the neck of the mandibular condyle. It crosses the lateral side of the lateral pterygoid muscle and enters the pterygomaxillary fissure. It is divided into a first or mandibular part, second or pterygoid part and third or pterygopalatine part. The mandibular and pterygoid parts are associated with the infratemporal fossa and the pterygopalatine part is associated with the deep face and the nasal region that is pterygopaltine fossa The mandibular portion of the maxillary artery has 5 branches, all entering a canal: The middle meningeal artery is the principal artery to periosteal dura of the cranial cavity. It is clinically important artery of epidural heamatoma. It has two divisions. Page 25 For medical students “au 2nd batch: many many, hard and soft:
  26. 26. Anatomy of head and neck By Amenu Tolera 2010 Tolera, The inferior alveolar artery runs into the mandibular foramen and supplies the teeth and the mandible. The angle of the mandible is poorly supplied and may suffer from alveolar osteitis (dry socket). The deep auricular artery supplies the auditory meatus .The anterior tympanic artery accompanies the chorda tympani through the petrotympanic fissure to reach the middle ear. The accessory meningeal branch (inconsistent) enters the foramen ovale and supplies the trigeminal ganglion and the surrounding dura. The pterygoid portion of the maxillary artery has 4 branches supplying muscles of mastication in the infratemporal fossa: 2 deep temporal branches, a masseteric branch, a pterygoid branch, and a buccal branch. The pterygopalatine portion of maxillary artery has 6 branches supplying the deep face, teeth and nasal region. Posterior superior alveolar, infraorbital, greater palatine, pharyngeal artery of pterygoid canal, Sphenopaltine arteries, which is the terminal branch of maxillary artery. 3. The pterygoid plexus of veins follows the maxillary artery in the infratemporal fossa, lying mostly lateral to the artery. This is a route for infection: the veins have connections with the cavernous sinus via the deep facial, inferior ophthalmic and emissary veins in the sphenoid bone. Veins of the head have NO valves. That is pterygoid plexus communicates with : Page 26 For medical students “au 2nd batch: many many, hard and soft:
  27. 27. Anatomy of head and neck By Amenu Tolera 2010 Tolera, a. inferior ophalmic vein via inferior orbital fissure b. cavernous sinus via emissary veins c. facial vein via deep facial vein 4. Mandibular division of the trigeminal nerve with its branches The trigeminal nerve (CN V) The trigeminal nerve lies in the floor of the middle cranial fossa, on the petrous temporal bone. It forms the trigeminal ganglion from which its three branches diverge. The mandibular nerve passes out of the skull through the foramen ovale. It is a sensory nerve to the skin over the mandible, the mandibular teeth, tongue and floor of the mouth, and motor to the muscles of mastication, the mylohyoid, tensor tympani and palati and the anterior belly of digastric. The lingual branch of the mandibular carries taste fibres for the anterior two-thirds of the tonge. These taste fibres originate in the facial nerve as the chorda tympani. The maxillary nerve passes along the lateral wall of the cavernous sinus to leave the skull through the foramen rotundum in the sphenoid bone. The nerve is entirely sensory and innervates the skin over the maxilla, the maxillary teeth, the mucous membrane of the nose and maxillary sinus, and the palate. The ophthalmic nerve passes along the side of the cavernous sinus to pass into the orbit through the superior orbital fissure. The nerve supplies sensory fibres to the cornea, eyelids, mucous membrane of the air sinuses and nasal cavity, and the skin on the nose. Direct injuries due to fractures of the base of the skull and penetrating objects are the two main causes of injury to the trigeminal ganglion. The ophthalmic and infraorbital nerves may be injured in trauma to the face. The mandibular division is rarely injured except for its inferior alveolar nerve in cases of mandibular fracture. Page 27 For medical students “au 2nd batch: many many, hard and soft:
  28. 28. Anatomy of head and neck By Amenu Tolera 2010 Tolera, Mandibular nerve is the only mixed modality of trigeminal nerve which goes via foramen ovale. It is organized into main trunk, a larger posterior and a smaller anterior divisions. From the common main trunk: It gives one sensory branch is meningeal branch called nervous spinosum and one motor to medial pterygoid muscle. The branch to this muscle also supplies tensor veli paltini and tensor tympani. From the smaller Anterior Trunk it gives one sensory, The buccal nerve and three motor , Masseteric branches , Posterior and anterior temporal branches to the temporalis muscle and The nerve to the lateral pterygoid. The buccal nerve of V3: passes between the 2 heads of the lateral pterygoid muscle. Continues into the cheek on the lateral surface of the buccinator muscle. Is the terminal branch of the anterior division is sensory to the mucosa of the inside of the cheek and the lower gums around the molar teeth. Does not supply the motor innervation of the buccinator. From the larger Posterior trunk: it gives three sensory, the Auriculotemporal nerve, lingual , Inferior alveolar (dental) nerve and one motor branches nerve to mylohyoid which also supplies the anterior belly of digastric as well.. Auriculotemporal nerve: Arise as two roots and leaves V3 just inferior to the foramen ovale and projects posteriorly in the infratemporal fossa parallel to the roof. The initial segment encircles the middle meningeal artery as the artery ascends to enter the foramen spinosum and receives postganglionic parasympathetic fibers from the otic ganglion which are secretomotor to the parotid gland. Passes medial to the head of the mandibular condyle and sends a sensory branch to the TMJ. Enters the deep portion of the parotid gland giving sensory branches as well as parasympathetic postganglionic fibers from the otic ganglion. Its terminal portion accompanies the superficial temporal artery and innervates the upper half of pinna of the ear and part of the temporal region (Pain and general sensation). Inferior alveolar (dental) nerve. From the foramen ovale to the mandibular foramen on the medial aspect of the ramus of the mandible, lying between the medial and lateral pterygoid muscles and just posterior to the lingual nerve . The branch to mylohyoid and to the anterior belly of the digastric is the only branch in the infratemporal fossa. It first lies in the mylohyoid groove, and then on the inferior aspect of the mylohyoid to reach the digastric muscle . The portion of the inferior alveolar nerve in the ramus of the mandible is entirely sensory to lower teeth, lower gums and the mucosa of the lower lips. It exits the mandible as the mental nerve to innervate the mucosa and gum adjacent to the lower lip. Lingual nerve. Lies anterior to the inferior alveolar nerve and remains medial to mandible. Receives the chorda tympani in the infratemporal fossa. The chorda tympani reaches the infratemporal fossa via the petrotympanic fissure . The chorda tympani contain preganglionic parasympathetic secretomotor fibers of VII from the tympanic plexus and special sensory fibers for taste from the anterior 2/3 of the tongue. The taste fibers have their cell bodies in the geniculate ganglion of VII. Terminal distribution of the lingual nerve and associated fibers which mediate general sensation (pain, touch temperature and pressure) is to the floor of the mouth and the anterior 2/3 of the tongue. Clinical Anatomy. Mandibular nerve block technique: Injection of anesthetic is performed in the fascial compartment defined by the fascial covering of the medial pterygoid and the medial Page 28 For medical students “au 2nd batch: many many, hard and soft:
  29. 29. Anatomy of head and neck By Amenu Tolera 2010 Tolera, aspect of the ramus of the mandible. The anesthetic diffuses to the lingual and inferior alveolar nerves. 5. Temporomandibular joint (TMJ; is an articulation between head of mandible and Mandibular fossa and articular tubercle of the temporal bone Synovial joint with intraarticular disc dividing joint into a lower compartment (hinge rotation for mandibular head) and upper compartment (sliding joint for protrusion). Minor supportive elements of the TMJ are : Lateral temporomandibular ligament (thickening of the joint capsule , Stylomandibular ligament (between parotid and submandibular glands; Sphenomandibular ligament. Movements of the mandible: Elevation, Depression, Protrusion and Retraction and side to side movements. Which muscle does these movements? Pterygopalatine or sphenopalatine fossa Is the fossa which lies between pterygoid plate, body of sphenoid bone and maxilla. It has five communications 1. Anteriorly: with orbit via inferior orbital fissure 2. posteriorly: with middle cranial fossa via foramen, pterygoid canal via foramen lacerum and pharynx with via palatovaginal canal 3. Medially: with nose via sphenopalatine foramen 4. Laterally: with infratemporal fossa via pterygomaxillary fissure 5. Inferiorly: with the oral cavity via greater and lesser palatine nerves. The major contents of pterygopalatine fossa are 1. 3rd part of maxillary artery with its six branches 2. Maxillary nerve with its eight branches. This include zygomztic with its zygomaticotemporal and zygomaticotemporal nerves, posterior superior alveeolar, anterior superior alveolar, middle superior alveolar, infraorbital and the three terminal branches palpebral, nasal and labial branches. 3. Pterygopalatine ganglion: is a parasympathetic ganglion supplies the lacrimal gland and gland of nose, palate and pharynx. Its preganglionic fibers arise from superior salivatory nucleus of lacrimation of CN VII via greater petrossal nerve with nerve of the pterygoid canal forms pterygopalatine ganglion. Postganglionic fibers supply secretomotor nerves to lacrimal gland and mucous gland of the nose, paranasal sinuses, palate and nasopharynx. The sympathetic are from superior cervical ganglion around internal carotid plexus as deep petrosal forms nerve of the pterygoid canal as pterygopaltine ganglion .This fibers does not synapse in the ganglion but pass to supply vasomotor innervation to mucus membrane of nose, paranasal sinus, palate and nasophynx. The sensory root comes from maxillary nerve and pass via the ganglion without synapse. Page 29 For medical students “au 2nd batch: many many, hard and soft:
  30. 30. Anatomy of head and neck By Amenu Tolera 2010 Tolera, ANATOMY OF THE NECK Definition: it part of a body that lies between the head superiorly and the thorax inferiorly. It is bounded by: superior nuchal line, posterior and anterior mid saggital plane, mandibular margin and superior border of the clavicle. . Skin: is just like other parts of the body unlike that of the skin of the face Superficial fascia: Contains platysma and sternocliedomastoid muscles, neurovascular bundles and lymph nodes. Deep fascia: (see cross section of neck):Is portioned into six fascia to ensheath structures of the neck. It includes: 1. Superficial (investing) layer of deep cervical fascia-surrounds all of the deeper parts of the neck and splits to enclose the platysma and SCM muscles. Is attached superiorly along the mandible ,mastoid process, EOP, and superior nuchal line of the occipital bone. Is attached inferiorly along the acromion of sacpula, clavicle and manubrium of sternum 2. prevertebral layer of deep cervical fascia: Is cylinderical and encloses the vertebral column and its associated muscles. Covers the scalene muscles and deep muscles of the back. Attached to EOP and basilar part of the occipital bone and becomes continous with the endothoracic fasica and anterior longitudinal ligament of the bodies of vertebra in the thorax 3. Carotid sheath: is formed by thickening of deep fascia to enclose the common carotid arteries, vagus nerve , internal jugular vein, deep cervical lymph nodes and some times ansa cervicalis. It doesn't contain the sympathetic trunk which lies posterior to carotid sheath and anterior to prevertebral fascia. Blends with the prevertebral,pretracheal,and investing layers and also to the base of the skull. 4. Pretracheral layer of deep cervical fascia Invests larynx and trachea,enclosingthe tyroid gland,and contributing to the formation of carotid sheath. Attaches superiorly to the thyroid andcricoid cartilagesand inferiorly to pericardium 5. Buccopharyngngeal fascia Page 30 For medical students “au 2nd batch: many many, hard and soft:
  31. 31. Anatomy of head and neck By Amenu Tolera 2010 Tolera, Covers the buccinator muscles and the pharynx. Is attached to pharyngeal tubercle and pterygomandibular raphe. 6. Pharyngobasilar fascia Is fibrous coat in the wall of the pharynx , situated between the mucus membrane and the pharyngeal constrictor muscles. Muscles of the neck In the anterolateral aspect of the neck there are ten muscles: two superficial, four suprahyoid and four infrahyoid The two superficial muscles muscle origin insertion action innervations Page 31 For medical students “au 2nd batch: many many, hard and soft:
  32. 32. Anatomy of head and neck Platysma: By Amenu Tolera 2010 Tolera, fascia or skin inferior border tenses the skin of the neck & draws facial nerve over of mandible or corner of mouth skin of lower pectoralis face majoror deltoid muscles Sternocleidomastoid sternum and mastoid flex forward the neck when both accessory nerve clavicle. process of the sides contract (CNIX) skull The four suprahyoid muscles muscle origin Digastric inferior border mandible insertion action hyoid bone open mouth and elevate trigeminal (anterior belly) & hyoid bone facial nerves (posterior belly) of innervation body of elevate hyoid bone and trigeminal nerve of hyoid bone floor of mouth Mylohyoid inferior border mandible Stylohyoid Styloid process body of elevate & retracts tongue of the hyoid bone temporal bone facial nerve geniohyoid genial tubercle body hyoid 1st cervical nerve of depresses mandibel The four infrahyoid muscles Page 32 For medical students “au 2nd batch: many many, hard and soft:
  33. 33. Anatomy of head and neck By Amenu Tolera 2010 Tolera, Strenohyoid:- manubrium body bone of hyoid : depress hyoid bone Sternothyroid: manubrium thyroid cartilage depress thyroid cartilage Thyrohyoid thyroid cartilage Omohyoid superior border scapula great cornu hyoid bone ansa cevicalis ansa cevicalis of depress hyoid bone & elevate C1 nerve thyroid inferior border of depress hyoid bone of hyoid bone ansa cevicalis Approaches to the neck anatomy Is best described by dividing into 2 major and 6 minor triangular regions using sternocliedomastoid, omohyoid and digastric muscles on the anterolateral aspect. Posteriorly there is also suboccipital triange. Two major are one infront and the other behind SCM. Triangles of neck Page 33 For medical students “au 2nd batch: many many, hard and soft:
  34. 34. Anatomy of head and neck By Amenu Tolera 2010 Tolera, Six minor triangles are: occipital and subclavian triangles of posterior triangles separated by omohyoid posterior belly. Submandibular, submental,carotid and muscular triangles of anterior triangle separated by omohyoid anterior belly,digastric anterior and posterior bellies and hyoid bone. Define the boundary, roof, floor, main contents of each triangle and description of each content as well as applied anatomy of each triangle. What are the boundaries the anterior and posterior triangles of the neck and the boundaries of minor triangles of the neck? The borders of posterior triangle are: 1. Posterior border of sternocliedomastoid: anterior border 2. Anterior border of trapezius: posterior border 3. Intermediate third of clavicle: inferior border The borders of anterior triangle are: 1. Anterior border of sternocliedomastoid: posterior border 2. Base of mandible: superior border 3. Midline of the neck: anterior border The borders of SUBMANDIBULAR TRIANGLE are 1. Posterior belly of Digastric: Lateral border 2. Anterior belly of Digastric: Medial border 3. Mandible: Superior borderBorders: The borders of CAROTID TRIANGLE are 1. Superior Belly of the Omohyoid: Medial Border 2. Posterior Belly of the Digastric: Superior Border 3. Sternocleidomastoid: Lateral Border The borders of MUSCULAR TRIANGLE: 1. Superior Bellies of the Omohyoid: Lateral borders 2. Midline of the neck: Medial borders The borders of SUBMENTAL triangle are: 1. Anterior belly of digastric: right border 2. Posterior belly of digastric: left border 3. Hyoid bone : inferior border The roof of every triangle of the neck are 1. The skin 2. The superficial fascia with its contents. The floor every triangle of the neck is made up of muscles 1. The floor of posterior triangle is made of above downwards: semispinalis capitis, splenius captis, lavator scapula and scalenus medius. 2. The floor of carotid triangle is made of hyoglossus, thyrohyoid, and middle and inferior constrictor of the pharynx. 3. The floor of submental triangle is made of mylohyoid muscle Page 34 For medical students “au 2nd batch: many many, hard and soft:
  35. 35. Anatomy of head and neck By Amenu Tolera 2010 Tolera, 4. The floor of digasric triangle is made up of mylohyoid and hyoglossus 5. The floor of muscular triangle is made of sternohyoid, sternothyroid and thyrohyoid. The contents of the triangle are mainly neurovascular structures, glands and muscles. The contents of posterior triangle are: 1. vessels like the 3rd part of subclavian artery, transeverse cervical and suprascapular vessels and external jugular vein. 2. nerves like the three trunks of brachial plexus, branches of cervical plexus and the spinal accessory nerve. 3. lymph nodes like deep and superficial cervical lymph nodes. The contents of carotid triangle are: 1. vessels like common carotid artery and its branches and internal jugular vein 2. nerves like vagus , sympathetic trunk , ansa cervicalis and part of hypoglossal nerve 3. lymph nodes like deep cervical lymph nodes accompanying internal jugular vein The contents of digastric triangle are: 1. vessels like a part of facial artery and anterior facial vein 2. nerves like a part of hypoglossal nerve 3. lymph nodes like submandibular lymph nodes 4. gland like submandibular gland. The submental triangle are: 1. vessels like submental artery and vein 2. lymph nodes like submental lymph nodes The contents of muscular triangle are> 1. muscles like infrahyoid muscles Clinical Anatomy: DANGER triangle of the neck : That part of the posterior triangle inferior to the Spinal Accessory Nerve. It contains: The Spinal Accessory Nerve (XI) and Brachial Plexus. Hence injury to this nerves cause a lot of syndromes. Give a short account on the major contents of each of the triangles? 1. The Cervical plexus Formation: The ventral primary rami of upper four spinal nerves ( C1, C2, C3, and C4) form a network of nerves known as the cervical plexus. There is some contribution to the plexus from C5. This plexus just like any other plexus gives branches. Branches: It has four cuntanous and five muscular branches. The cutanous branches are: 1. lesser occipital nerve (C2) 2. Greater auricular nerve (C2 and C3) 3. transeverse cervical nerve(C2 and C3) 4. supraclavicular nerves( C3 and C4). The muscular branches are: 1. nerve to sternocliedomastoid (C2) 2. nerve to trapezius (C3 and C4) 3. nerve to levator scapula (C3 and C4) 4. nerve to diaphragm, the phrenic nerve(C3,C4 and C5) 5. nerve to infrahyoid muscles, the ansa cervicalis ( C1, C2 and C3) Page 35 For medical students “au 2nd batch: many many, hard and soft:
  36. 36. Anatomy of head and neck By Amenu Tolera 2010 Tolera, 2. The ansa cervicalis Formation: is a nerve loop formed in the neck by union descendsens hypoglossi or the superior root (C1) and descendens cervicalis or the inferior root(C2 and C3). Distribution: It lies inside or infront of the carotid sheath and supplies all infrahyoid muscles except thyohyoid, which is supplied by C1 via hypoglossal fibers. Draw the ansa cervicalis ? 3. The Accessory nerve The spinal accessory nerve is the motor nerve to the sternocleidomastoid and trapezius muscles . It arise by two roots. The cranial root arises from nucleus ambigus in the medulla and the spinal root from the upper five cervical spinal segments of the spinal cord. The spinal root ascends in the vertebral canal reaching the cranial cavity via foramen magnum. The two roots merge in the jugular foramen and again split below the jugular foramen. The cranial accessory joins vagus nerve and distribute with its pharyngeal and laryngeal branches. This tells you why it is so named. The spinal accessory descends in the neck in the neck crossing internal jugular vein , passes deep to styloid process,posterior belly of digastric and occipital artery. Then passes deep to sternocliedomastoid supplying it and crosses the posterior triangle and then passes deep to trapezius supplying it. NERVE GRAFTS: The function of Spinal Accessory is somewhat redundant. Clinical anatomy: accessory nerve can be used to replace innervation lost by other muscles. The nerve can be redirected to the muscles of facial expression, e.g., and patients can learn to use the new pathway with physical therapy. Page 36 For medical students “au 2nd batch: many many, hard and soft:
  37. 37. Anatomy of head and neck By Amenu Tolera 2010 Tolera, 4. Carotid sheath A protective deep fascia which encloses larger neurovascular structures of the neck in the carotid triange. It contains common carotid artery and its branches more medially, internal jugular vein more laterally with its accompanying lymph nodes, and vagus nerve in the middle between the two. Some times it also contains ansa cervicalis. The sympathetic trunk lies posterior to the sheath. 5. The Common carotid arteries. Page 37 For medical students “au 2nd batch: many many, hard and soft:
  38. 38. Anatomy of head and neck By Amenu Tolera 2010 Tolera, They arise from arch of aorta on the left and from brachiocephalic trunk on the right. Each carotid artery ascends the neck in a connective tissue sheath which encloses the vagus nerve and the internal jugular vein. The internal jugular vein lies lateral to the common carotid artery with the vagus nerve in between. At the upper border of the thyroid cartilage the common carotid arteries divide to form the internal and external carotid arteries . Just at bifurcation point there is carotid body, which is a chemoreceptor, innervated by nerve to carotid body and sinus from CNIX and CNX. At the beginning of the internal carotid there is a dilation called carotid sinus, which is a baroreceptor, innervated by branches of vagus and glossopharyngeal nerves. The external caroid artery: Have six side and two terminal branches in the neck. This are ascending pharyngeal, superior thyroid, facial, lingual, posterior auricular and occipital arteries as side branches and superficial temporal and maxillary as terminal branches. The external carotid arteries supply the muscles of the neck, the pharynx, larynx, thyroid, ears, mouth, nose, face and scalp. The named side branches are: 3 anterior branches 1. Superior Thyroid Artery -- Thyroid gland and part of anterior neck 2. Lingual Artery -- to tongue 3. Facial Artery---to face 1 medial branch 4. Ascending Pharyngeal Artery -- to pharynx 2 posterior branches 5. Occipital Artery -- back of neck and behind ear 6. Posterior Auricular Artery -- behind and around ear SUPERFICIAL TEMPORAL ARTERY: IS the smaller terminal branch of the External Carotid artery .Goes straight up the temporal region of the skull. Has three named branches: Anesthesiologists use it to take a pulse. It is found just anterior to the ear, superficial to the zygomatic arch. 1. Frontal Branch 2. Parietal Branch. 3. Transverse Facial Artery crosses Masseter muscle Page 38 For medical students “au 2nd batch: many many, hard and soft:
  39. 39. Anatomy of head and neck By Amenu Tolera 2010 Tolera, The internal carotid artery: has no branch in the neck. It vertically ascends and enters into the skull via carotid canal. Then it has tortous course and gives numerous branches as well. The internal carotid artery ascends to the base of the skull which it enters through the carotid canal. Entering the skull the artery passes anteriorly across the foramen lacerum and through the cavernous sinus. Emerging from the cavernous sinus the artery terminates by dividing into the anterior and middle cerebral arteries. There are no branches from the cervical part of the internal carotid. The ophthalmic artery is the largest of its intracranial branches leaving at the emergence from the cavernous sinus and entering the orbit by the optic canal to supply all of the structures of the orbit. Smaller branches also arise fro the internal carotid arery as it passes through the skull. These branches supply the meninges, the trigeminal ganglion, the pituitary gland, and the tympanic cavity. Page 39 For medical students “au 2nd batch: many many, hard and soft:
  40. 40. Anatomy of head and neck By Amenu Tolera 2010 Tolera, 7. The jugular veins The internal jugular vein: is a continuation of sigmoid sinus at jugular foramen. It has two bulbs, the superior bulb and the inferior bulb. Between the bulbs it has tributaries like inferior petrosal sinus, superior and middle thyroid veins, common facial vein, and anterior jugular vein. It descends in the neck and joins its corresponging subclavian vein forms the corresponding brachiocephalic veins. External jugular vein: is formed by union of posterior auricular vein and posterior division of retromndibular vein. It has tributaries like suprsacpularveins, transeverse cervical vein and anterior jugular vein. It descends in the neck anterior to SCM muscle and drain into its corresponding subclavian vein. Sometimes it may drain into internal jugular vein. Submandibular region Position : area between mandible and hyoid bone Contents: muscles like, stylohyoid, myleohyoid, geniohyoid, styloglosus, genioglossus, hyoglossus and digastric. Glands like sumandibular and sublingual salivary glands which are innervated by parasympathetic-chorda tympani from facial nerve and sympathetic –from superior cervical ganglion via plexus on facial artery. General sensory from lingual from mandibular division of trigeminal nerve. vessels like facial and Submandibular ganglion on hyoglossus muscle. Lymph nodes like submandibular lymph nodes which receive from submental lymph nodes and lymph from anterior 2/3 of the tongue, ½ of nasal wall, Lips and Paransal sinus The Salivary glands Page 40 For medical students “au 2nd batch: many many, hard and soft:
  41. 41. Anatomy of head and neck By Amenu Tolera 2010 Tolera, 1. Submandibular gland Is ensheathed by investing layer of the deep cervical fascia . Lies in submandibular triangle Its supericial portion is located superficial to mylohyoid muscle. Its deep portionis located betweenthe hyoglossus and styloglossus muscles medially and mylohyoid muscle laterally and between lingual nerve above and hypoglossal nerve below. Whartons duct arise from the deeper portion and runs foreward between the mylohyoid laterally and and hyoglossus laterlly , where it is crossed laterally by the lingual nerve.then it runsbetween sublingual gland and and the genioglossus andempties at the summit of sublingual papilla(caruncle) at the side of frenulum of the tongue. Is innervated by parasympathetic secretomotor fibers from facial, which runs in chorda tympani and in lingual nerve and synapse in submandibular ganglion. 2. Sublingual gland Is located in the floor of the mouthbetween mucous membrane above and mylohyoid muscle below. Surround terminal portion of submandibular duct. Empties mostly into the floor of the mouth along sublingual fold by 12 short ducts,some of which enter the submandibular duct. Innervation is similar to submandibular gland 3. parotid gland (see back ) Midline and deep structures of the neck It includes: Cervical part of trachea and esophagus, Thryroid gland, Parathyroid glands, Cervical sympathetic trunk , larynx and hyoid bone. Trachea Begins at inferior border of the cricoid cartilage(C6 vertebrae ) Has 16-20 C-shaped cartilages, preventing trachea from collapse. Bifurcates at opposite lower border of T4 vertebrae (sternalangle). Its bifurcation lies slightly to the right of median plane. Esophagus: Is covered with pretacheal fascia and lies posterior to trachea and anterior to prevertebral fascia Thyroid gland: Is and endocrine gland that produces tyroxine and thryocalcitonin. Consist of right and left lobes connected by the isthmus, which lies in front to 2-4th tracheal rings. Sometimes muscular band descending from body of hyoid bone to the pramidal lobe of the Page 41 For medical students “au 2nd batch: many many, hard and soft:
  42. 42. Anatomy of head and neck By Amenu Tolera 2010 Tolera, isthmus is levator glandulae thyroidae. The isthmus is coverd anteriorlyby the skin,superficial fascia containing anterior jugular veins,deep fascia and sternothyroid and tyrohyoid. Thryoid gland is supplied 3 arteries and drained by 3 veins. Superior thyroid artery from ECA Inferior thyroid artery from thyrocevical trunk Thyroidae ima artery,an inconsistent branch from the brachiocephalic trunk These arteries form anastomosis especially the two superior thyroid arteries. Superior thyroid vein drain to internal jugular vein Middle tyroid vein drain to internal jugular vein Inferior thryroid vein drain to the left brachiocephalic vein. Lymphatics from thyroid drain into lower deep cervical, prelaryngeal, pretracheal and paratracheal lymph nodes. Innervated by ANS, sympathetic via thyoid branches along inferior thyroid artery from middle cervical ganglion Parasympathetic from vagus Why thyroid gland moves up and down with deglution? It is enclosed in the pretracheal fascia which fixes the gland to the larynx and trachea. Clinical anatomy Goiter: is a pathologic enlargement of the thyroid gland,causing a swelling in the front of the neck. Tracheotomy: is opening into trachea by incising the third and fourth rings of trachea, after making a vertical midline skin incision from jugular notch of manubrium sterni to the thyroid notch of the thyroid cartilage. Cricothyrotomy: is incision via the skin and cricothyroid membrane for relief acuterespiratory obstruction.Is preferable to tracheostomy for nonsurgeons in emergency respiratory obstructions Page 42 For medical students “au 2nd batch: many many, hard and soft:
  43. 43. Anatomy of head and neck By Amenu Tolera 2010 Tolera, Parathyroidectomy: may occur during total thyroidectomy,and cause death if PTH,calcium or Vitamin D is not provided. Decrease plasma caclium level,causing increasedneuromuscular activity such as muscular spasmsand nervous hyperexcitability,called tetany. Parathyroid glands: are endocrine glands that produce PTH, which plays vital role in regulation of calcium and phosphorus metabolism. Consist usually of four 2 superior and 2 inferior parathyroids (can vary from 2-6) small ovoid bodies( that lie againstthe dorsum of the thyroid under its sheath but with their own capsule. Arterial supply,venous and lymphatic drainge and innervation almost similar to thryroid gland. Sympathetic system Arise from intermediolateral grey columnfrom T1-L2 or L3. Enter ganglion as white rami communicantes. Leave ganglion as grey rami communicantes Three Fates of white rami May terminate in the ganglion of the sympathetic chain they enter by synapsing with excitor neuron. May enter a sympathetic ganglion and asend or desend to a higher or lower levels of respectively(of a ganglion)where it terminates. May pass through sympathetic ganglion at the level of origin without synapsing and form splanchnic nerve which synapse at a peripheral ganglion near the organ they innervate Cranial part of sympathetic system Originate as internal carotid nerve,postganglionic branch from the upper end of superior cevical ganglion. Enters cranial cavity through carotid canal and divides into medial and lateral branches which unite and form internal carotid plexus. Cervical sympathetic system has three cervical ganglia and has no white rami communicants 1. The superior cervical ganglia is the largest, lies at the level opposite C2 or C3 Medial (visceral)branches o laryngopharyngeal branch to carotid body andpharyngeal plexus o cardiac branches to left and right superficial and deep cardiac plexus respectively Page 43 For medical students “au 2nd batch: many many, hard and soft:
  44. 44. Anatomy of head and neck By Amenu Tolera 2010 Tolera, Anterior( vascular) branches to o Arterial branches to common carotid and external carotid via branches of trigeminal to parasympathetic ganglia. o Lateral (somatic)branches to cranial nerves,superior jugular bulb,and meninges of posterior cranial fossa. Give rise to internal and external carotid nerves and superior cervical cardiac nerve to the heart. 2. Middle cervical ganglion o Lie at level of C6,branches to thyroid, heart, esophagus and trachea o Give rise to cervical cardiac nerve 3. Inferior (cervicothoracic) ganglia o Lies between transverse process of C7and neck of 1st rib, branches to subclavian,vertebraland heart (inferior cardiac plexus) o Give rise to inferior cervical cardiac nerve What is ansa subclavia? o Is the cord connecting the middle and inferior cervical sympathetic ganglia forming loop around the 1st part of subclavian artery. SYMPATHETIC INNERVATION HEAD AND NECK Vasoconstrictor to blood vessels of skin and viscera Secretomotor to sweat glands Dilator to the pupil Motor to dilator pupilae of the iris and smooth muscle fibers of levatorpalpebra superioris Sympathetic dennervation (Horner’s syndrome) Is caused by injury to cervical sympathetic fibers. Is characterized by five symptoms 1. Miosis, pupillay constriction resulting from paralysis of the associated dilator muscle of the pupil 2. Ptosis, drooping of un upper eyelid from paralysis of smooth muscle component of the levator palpebrae superioris 3. Enophthalmos, retraction of an eye ballfrom paralysis of the superior tarsal muscle 4. Anhydrosis, absence of sweating,due to loss of secretomor fibers to sweat glands 5. Vasodilation, leading to increased blood flow in the facial and cervical region(loss of vasoconstriction) PARASYMPATHETIC INNERVATION HEAD AND NECK All Parasympathetic motor innervation to the head synapses exactly once, in one of the four cranial parasympathetic peripheral ganglia listed below. All of these ganglia are distributed along branches of the Trigeminal Nerve (V). 1. CILIARY GANGLION: Carries parasympathetics from Oculomotor Nerve (III) Located in the posterior of the orbit. GVE (Parasympathetic) innervation is to: 1. Ciliary Muscles (for Accommodation) 2. Sphincter of the Pupil (constriction, or miosis). It hangs off of the Ophthalmic Branch of the Trigeminal Nerve (V 1 ) 2. PTERYGOPALATINE GANGLION: Carries parasympathetics from Facial Nerve (VII) Located in the Pterygopalatine Fossa in the posterior part of sphenoid bone. Page 44 For medical students “au 2nd batch: many many, hard and soft:
  45. 45. Anatomy of head and neck By Amenu Tolera 2010 Tolera, GVE (Parasympathetic) innervation is to: 1. Nose 2. Palate 3. Lacrimal Glands It hangs off of the Maxillary Branch of the Trigeminal Nerve (V 2 ). 3. SUBMANDIBULAR GANGLION: Carries parasympathetics from Facial Nerve (VII) Located below and lateral to the tongue. GVE (Parasympathetic) innervation is to: 1. Submandibular Gland 2. Sublingual Gland It hangs off of the Mandibular Branch of the Trigeminal Nerve (V 3 ). 4. OTIC GANGLION: Carries parasympathetics from Glossopharyngeal Nerve (IX) Located in Intratemporal Fossa, just below Foramen Ovale. GVE (Parasympathetic) innervation is to the Parotid Salivary Gland. It hangs off of the Mandibular Branch of the Trigeminal Nerve (V 3 ) Don’t forget: VAGUS NERVE (CN X) has no parasympathetic ganglion in the head. But it sends parasympathetic innervation to the thoracic and abdominal viscera. THE MINOR BODY CAVITIES, TONSILS AND PARANASAL SINUSES. The oral cavity: Definition: The minor body cavity of head via which food is ingested Extent: from lips to oropharynx Divisions: two major parts the vestibule(between outer fleshy wall made of cheeks and lips and inner bony wall made of teeth and gums) the oral cavity proper (area inside teeth and gums). Roof: by hard palate anteriorly and soft palate posteriorly Floor: by tongue and the mucosa supported by the geniohyoid and mylohyoid muscles Teeth Definitions: is the hardest substance in the body. Sets: the 1st teeth is milky which replaced by permanent tooth starting from six months. Page 45 For medical students “au 2nd batch: many many, hard and soft:
  46. 46. Anatomy of head and neck By Amenu Tolera 2010 Tolera, Parts: crown and root separated by neck Type: human beings have hetrodont dention in which there are incisors, canines, premolars and molars on each quadrant from anterior to posterior Structure: tooth is composed of three hard tissues and three soft tissues Foramen: neurovascular structures enter into pulp chamber via apical foramen Neurovascular structures of teeth Page 46 For medical students “au 2nd batch: many many, hard and soft:
  47. 47. Anatomy of head and neck By Amenu Tolera 2010 Tolera, Nerve supply: 1. V3 supplies teeth and gums of mandibular arch. The inferior alveolar (dental) nerve innervates all the teeth in the mandible. The gums of the molars and bicuspids are innervated by the long buccal nerve .The gums of the incisors are innervated by the mental nerve. The lingual gums are innervated by the lingual nerve.The inferior alveolar nerve enters the mandibular foramen and passes via the mandibular canal forming the inferior dental plexus, which sends branches to all mandibular teeth on that side. The nerve to the myohyloid muscle, a small branch of the inferior alveolar nerve, is given off just before the nerve enters the mandibular foramen. A branch of the inferior dental plexus, the mental nerve, passes thru the mental foramen and supplies the skin and mucous membrane of the lower lip, skin of the chin, and vestibular gingival of the mandibular incisor teeth. 2. V2 supplies the teeth and gums of the maxillary arch. The molar teeth are supplied by the posterior superior alveolar nerve from the pterygopalatine fossa. The bicuspids (premolars) are innervated by the middle superior alveolar nerve from the infraorbital nerve. The canines and incisors are innervated by the anterior superior alveolar nerve from the infraorbital nerve The gums on the palatal surface are innervated by the nasopalatine nerve (incisors) and greater palatine nerve (bicuspids and molars). The blood supply to both jaws comes from superior alveolar artery from (1st part of maxillary artery) and inferior alveolar artery (from the 3rd part of maxillary artery) for the upper and lower jaws respectively. Venous drainage: The veins accompanying the arteries drain into maxillary vein Lymphatic drainge: Lymphatics from teeth drain into submental or submandibular lymph nodes. Tongue (2, 3,5,8 best ) Definition: is a muscular organ located in floor of the mouth Attachement: is attached by muscles to the hyoid bone , mandible,styloid process,palate and pharynxFunction: associated with functions like taste,mastication,speech, and deglution(swallowing) Parts: has two oral (anterior 2/3) and pharyngeal (posterior 1/3) by a V-shaped sulcus ,the sulcus terminalis.which differ developmentally, structurally and in innervation. foramen ceacum is located at apex of the V and indicates the site of origin of embryonic thyroglossal duct. Root of tongue is attached to mandible above and hyoid bone below. Tip of tongue is the anterior free end of the tongue,which at rest lies behind the upper incissor teeth. Surfaces: it has an upper (dorsal )rough and a lower(ventral) smooth surfaces. Page 47 For medical students “au 2nd batch: many many, hard and soft:
  48. 48. Anatomy of head and neck By Amenu Tolera 2010 Tolera, The dorsal surface of the tongue is convex in all directions. Is rough due to projections of mucus membrane forming four papillae (see histology). Ventral surface of the tongueis smooth. Has pelica fimbriata,deep lingual vein,sublingual paillae, lingual fold, and frenulum Muscles: a midline septum divide the tongue into right and left haves. Each half consist of 4 intrinsic and 4 extrinsic muscles:Muscles of tongue only eight pairs The four intrinsic muscles originate and end in the tongue it self and change the shape of the tongue. Includes four longitudinals 1. Superior longitudinal-shortens 2. Inferior longitudinal-shortens 3. Vertical longitudinal-flatens and broadens it 4. Transeverse longitudinal-narrows and elongate it The four extrinsic muscles of the tongue originate outside the tongue and end in the tongue (hence all have the suffix---glossus) and change the position of the tongue (protrude or retract, elevate or depress),includes the four glossus muscles differing in their origin 1. Genioglossus-protrude 2. Hyoglossus-depress 3. Palatoglossus-elevates 4. Styloglossus-retracts Nerurovascular structures of the tongue Five (2 motor and 3 sensory) Nerves go to the tongue A. Motor: one exception. All muscles of the tongue are innervated by hypoglossal nerve (CN XII) except palatoglossus which is innervated by vagus (CN X). B. Sensory: is it general or special and to anterior 2/3 or posterior 1/3 ? 1. Glossopharngeal nerve (CN IX) is both general special sensory to the posteior 1/3 of the tongue. 2. Facial nerve(CN VII) via chorda tympani branch is special sensory (taste) to anterior 2/3 of the tongue. 3. Trigeminal(CN V) via lingual nerve is general sensory to the tongue. CN 12+10+9+7+5=higher one, s motor and lower ones sensory to tongue. Page 48 For medical students “au 2nd batch: many many, hard and soft:
  49. 49. Anatomy of head and neck By Amenu Tolera 2010 Tolera, The lingual nerve: lies anterior to inferior alveolar nerve. It is sensory to the anterior two thirds of the tongue, the floor of the mouth, and the lingual gingivae. It enters the mouth between the medial pterygoid and the ramus of the mandible and passes anteriorly under cover of the oral mucosal, just inferior to the third moral tooth. The chorda tympani nerve: a branch of CN VII, carries taste fibers from the anterior two thirds of the tongue and presyn para secretomotor fibers for the submandibular and sublingual salivary glands. The chorda tympani joins the lingual nerve in the infratemporal fossa. The Hypoglossal nerve: Originates from medulla oblongata from its anterior aspect. Exits through hypoglossal canal. The hypoglossal nerve enters the floor of the mouth on the lateral aspect of the hyoglossus muscle, above the hyoid bone and the mylohyoid muscle .is a content of superior part of caroid triangle. Cranial nerve XII lies inferior to the lingual nerve and is purely motor to the muscles of the tongue except palatoglossus.(Somatic motor). Three Blood supply to tongue Three main arteries but lingual artery does the most a. lingual artery-from ECA b. Tonsilar artery –from facial-from ECA c. asending pharyngeal artery- from facial-from ECA. d. Three Venous drainage of the tongue Three veins drain it but deep lingual vein does the most. The veins accompany the arteries (venae commtantes) drain into their coorsponding veins. Three Lymphatic drainage Lymphatics from the different parts of the tongue form afferents to three lymph nodes a. From tip of tongue –to submental LN b. From right and left haves of rest lateral side of anterior 2/3 of the tongue-to submandibular LN c. From posterior 1/3 of the tongue-to jugulo-omohyoid LN Clinical anatomy Unilateral injury of hypoglossal nerve: Have three effects a. On protrusion of tongue-deviation is ipsilateral b. On retraction of the tongue-paralised side higher than unparalysed side c. On swallowing –larynx deviates towards normal side. Bilateral injury of hypoglossal nerve: Page 49 For medical students “au 2nd batch: many many, hard and soft:
  50. 50. Anatomy of head and neck By Amenu Tolera 2010 Tolera, Results in a. motionless tongue b. low articulation of sound c. difficulty of swallowing (patient need to push bolus of food with fingure or throw head back) Tongue tie (anklogossia): is abnormalshortness offrenulum lingulae, resulting in limitation of its movement and thus severe speech impaidment can be corrected by surgical innterventions cutting the frenulum. Palates Definition: a partion between oral and nasal cavity forming the roof and floor them respectively. Parts: two, soft vs. Hard palates Hard palate: is the anterior 4/5 of the palate, and forms a bony frame work covered with mucous membrane. formed by palatine process of maxillae and horizontal plate of palatine bone. Contains incisive foramen in median plane anteriorly and the grater and lesser palatine foramina posteriorly. Get sensory innervation from greater palatine and nasoplatine nerves. Get blood supply from greater and lesser palatine arteries. Get drained by veins accompanying the arteries Soft palate: Is the posterior 1/5 of palate extending from posterior border of hard palate.Is moveable and separates nasopharynx from oropharynx. Moves posteriorly against the pharyngeal wall to close the oropharyngeal (faucial) isthmus when swallowing or speaking. Has conical projection that hangs at middle of its inferior border,the uvula.Is a muscular fold continuous with The anterior fold-palatoglossal arch(fold) which contains palatoglossus muscle. The posterior fold palatopharyngeal arch(fold)which contains palatopharyngeus muscle.in between the two folds is palatine tonsil. Is made up of five muscles: 5 Muscles of soft palate 1. Tensor veli palatini-tenses soft palate and opens auditory tube 2. Levator veli paltini-elevates soft palate and closes orophryngeal tsthmus as well as opens auditory tube. 3. Palatoglossus-pulls up root of the tongue(elevates)and closes oropharyngeal isthmus 4. Palatopharyngeus-pulls up the wall of pharynxand shortens it during swallowing (elevatespharynx and close nasopharynx) 5. Musculus uvulae-pulls up (elevates uvula) Neurovascular structures of soft palate Four (2 motor and 2 sensory) nerves go to the soft palate A. Motor: one exception All muscles of the palate are innervated by vagus via pharyngeal plexus except tensor veli paltini which is innervated by mandibular branch of trigeminal nerve B. Sensory: lesser platine nerve a branch from maxillary nerve glossophrengeal nerve (lateral part). Three Blood supply to soft palate Three arteries from different sources are distributed to soft palate 1. Greater and lesser palatine arteries from descending palatine artery of maxillary artery 2. Asending palatine artery of facial artery 3. Palatine branch of ascending pharyngeal artery Venous drainage of soft palate Veins accompanying the arteries from soft palate drain to into either pterygoid plexusof veins or tonsillar plexus of veins. Lymphatic drainage of soft palate Lymphatics from soft palate drain into upper deep cervical or retopharyngeal LN. Tonsils Definition: aggregation of lymphoid tissues that form a ring around oropharyngeal isthmus for immune purpose. Page 50 For medical students “au 2nd batch: many many, hard and soft:
  51. 51. Anatomy of head and neck By Amenu Tolera 2010 Tolera, . Types: four types forming one tonsilar (waldeyer,s) ring. Pharyngeal tonosil-is found in the posterior wall and roof of nasopharynx. Lingual tonsil-is found root of the tongue Tubal tonsil-found neat the pharyngeal opening of the auditory tube.Palatine tonsil-lies in tonsillar fossa bounded by palatoglossal and platophryngeal folds,and is pyramidal in shape. Has lateral and medial surfaces,superior constrictor of the pharynx is related just deep to paltine tonsil next to paratonsillar vein. thirdly is the styloglosus muscle. Neurovascular structures of tonsil 2 nerves go to tonsil 1. Get sensory innervations from tonsillar branch of glossophayngeal nerve 2. lesser palatine branch of maxillary nerve Tonsil has rich blood supply Eight arteries supply tonsil but tonsillar branch of facial does the most. a. Inferior pharyngeal –from inferior thyroid b. Superior laryngeal-from superior thyroid c. Dorsal lingual-from lingual artery d. Asending palatine –from facial e. Tonsilar –from facial f. Desending palatine –from maxillary g. Artery of pterygoid canal-from maxillary h. Greater palatine-from descending palatine Venous drainage of tonsil Tonsillar veins drain into lingual or pterygoid plexus of veins and facial vein Lymphatic drainage of tonsil Tonsillar lymph nodes drain into jugulodigastric or other cervical lymph n odes. Clinical anatomy Waldeyer,s lymphatic ring: surround the opening into respiratory and digestive tube includes: a. Anterior and lower par of the ring is formed by-lingual tonsil b. Lateral portion by-paltine and tubal tonil c. Behind and above by-pharyngeal tonsil Adenoid:is hypertrophy or enlargement of phayngeal tonsilobstructing passage of air from the nasal cavity though choanae into nasophaynx, resulting in impariment of hearing and deafness (ottitis media). Tonsillectomy: surgical removal of tonsil,may cause much bleeding because of their rich vascularity and related to internal carotid artery. may injure lingual branch of glossopharngeal and lingual nerve of mandibular. Page 51 For medical students “au 2nd batch: many many, hard and soft:
  52. 52. Anatomy of head and neck By Amenu Tolera 2010 Tolera, Nasal cavity and paranasal sinses The nasal cavity opens on the face through the anterior nasal aperture (nares or nostrils and communicates with the nasopharynx through a posterior opening, the choanae Page 52 For medical students “au 2nd batch: many many, hard and soft:
  53. 53. Anatomy of head and neck By Amenu Tolera 2010 Tolera, Roof : is formed by the nasal,frontal, ethmoid,(cribriform plate),and sphenoid (body) bones .the cribriform plate transmits the olifactory nerves. Floor: is formed by palatine process of maxilla and the horizontal plate of the palatine bone.incisive formamen transmits the nasopalatine nerve and terminal branch of sphenopaltine artery. Medial wall (nasal septum): formed primarly by perpendicular plate of the ethmoid bone,vomerand septal cartilage,is also formed by processes of palatine, maxillary,frontal ,sphenoid and nasal bones. Lateral wall: is formed by the superior and middle conchae of the ethmoid bone and the inferior conchae. Is also formed by the nasal bone, frontal proceses and nasal surface of maxilla,lacrimal bone, perpendicular plate of palatine bone, and medial pterygoid plate of of the sphenoid bone. Contains the following structures and openings: Which wall is this one? Nasal chonca Definition: are shelf like or scroll-likebony projectionsdirected downwards and medially 1. Inferior concha-is an independent bone 2. Middle concha is a projection from medial surface of ethmoidal labrynith 3. Superior concha –is a projection frommedial surface of ethmoidal labyrnith(smallest ) Function: increase surface area of the nose for effective conditioning of inspired air (turbines of the nose) Meatuses of the nose Definition: are passages beneath the overhanging conchae Types; three only why? Inferior meatus: lies beanth the inferior concha and is the largest turbinate. nasolacrimal duct opens into it at the junctionof anterior 1/3 and posterior 2/3. Middle meatus; lies underneath the middle chonae. It presents three features: 1. opening of frontal air sinus into the infundibulum 2. openings of the middle ethmoidal air cells on the ethmoidal bulla. 3. openings of the anterior ethmoidal air cells and maxillary sinus in the hiatus semilunaris Superior meatus: underneath the superior conhae. Shortest and shallowest. receives openings of posterior ethmodal air cells Note: all paranasal sinuses open into meatuses of nasal cavity except sphenoidal air sinus which opens into spheno-ethmoidal recess, a triangular fossa above superior concha. Three Sub-divisions and mucous membranes Page 53 For medical students “au 2nd batch: many many, hard and soft:
  54. 54. Anatomy of head and neck By Amenu Tolera 2010 Tolera, 1. Vestibule: is the dilated part inside the nostril that is bounded by the alar cartilages and lined by skin with hairs. 2. Respiratory region: consists of the lower 2/3 of the nasal cavity. Its mucous membrane warms,moistens,and cleans incoming air 3. Olifactory region: consist of superior nasal conchaand upper 1/3 of the nasal septum.Is innervated by olifactory nerves,which convey sense of smell from the olifactory cells and enter cranial cavity through cribriform plate of ethmoid bone to olfactory bulb The Olfactory Nerve (CN I): This is the nerve of smell. Is a purely sensory nerve. The fibers that comprise this nerve are unmyelinated axons of olfactory cells that are located in the nasal mucosa.The axons of these cells unite to form 18 to 20 small nerve bundles that are known collectively as the olfactory nerve. Each of these nerves is covered by the three layers of meninges and pass through foramina in the cribriform plate of ethmoid bone and enter the olfactory bulbs in anterior cranial fossa and project to olifactory area of the cerbrum. Neurovascular bundles of the nasal cavity Six nerves (1 special sensory and five genral sensory goes to the nasal cavity 1. Special sensory(smell) is by olifactory nerve for the olifactory area 2. Genreal sensation: is by 3. anterior ethmoidal branch of V1 4. Nasopalatine,posterior-superior,and anterior inferiorlateral nasal branches of V2 viathe pterygopaltine ganglion 5. Anterior superior alveolar branch of the infraorbital nerve. Nasal cavity has rich blood supply Three major arteries supply the nasal cavity though their branches but spenopalatine artery of maxillary artery is clinically more important. why? Opthalmic artey via lateral nasal branches of anterior and posterior ethmoidal aa Maxillary artery via Posterior lateral nasal and posterior septal branches of sphenopalatine artery and via greater palatine artery Facial artery via septal branch of superior labial and lateral nasal branches Venous drainage of nasal Cavity Veins of nasl cavity form submucous plexus which empties into sphenopaltine vein,facial vein,opthalmic veins and superior saggital sinus via foramen ceaum. Lymphatic drainage Page 54 For medical students “au 2nd batch: many many, hard and soft: