Skull, Neck and Muscles By : Hermizan Halihanafiah Bsc Biomedical Sc (Hons), UKM email@example.com http://www.slideshare.net/hermizan84
Skull Contains 22 bones Rest superior to the vertebral column Consists 2 sets of bones, facial and cranial bones Cranial bones forms the cranial cavity, which encloses and protect the brain Facial bones form the face.
Function of the skull Protect the brain Inner surface attach to the membranes (meninges) that stabilize the position of the brain, blood vessels and nerves. Outer surface of cranial bones provide large areas for muscle attachment that move various part of the head. The bones also provide muscle attachment for some muscles that produce facial expressions.
Function of the skull Facial bones – forms framework of the face Facial bones – provide support for entrance to the digestive and respiratory system Together cranial and facial bones protect and support the delicate special sense organs for vision, taste, smell, hearing and equibilirium.
Frontal Bones Forms the forehead, the roof of the orbits and most of the anterior part of the cranial floor Soon after birth, the left and right side of the frontal bone united together by the metopic suture, usually disappear by age of six to eight.
Frontal Bones Frontal Bone that forms the forehead – Frontal squama Superior to the orbits the frontal bone thickens, forming the supraorbital margin. From this margin, the frontal bone extends posteriorly to form the roof of the orbits, which is part of the floor of the cranial cavity. Within the supraorbital margin, slightly medial to its midpoint, is a hole called supraorbital foramen where supraorbital nerve and artery pass through it.
Frontal Bones Frontal sinuses lie deep to the frontal squama. Sinuses, or called parasinuses, are mucous membrane – lined cavities in certain skull bones.
Parietal Bones 2 parietal bones Form the greater portion of the side and roof of the cranial cavity Internal surface of parietal bones contain many protrusion and depression that accommodate the blood vessels supplying the dura mater (superficial connective tissue that lining the brain. No foramina in the parietal bones.
Temporal Bones 2 temporal bones Form the inferior lateral aspects of the cranium and part of the cranial floor Lateral view of the temporal bones, called temporal squama, the thin, flat part that form the anterior and superior part of the temple. Projecting from the inferior portion of the temporal squama is the zygomatic process.
Temporal Bone Zygomatic process of temporal bones articulate with temporal process of zygomatic (cheek) bone form the zygomatic arch A socket called the mandibular fossa is located on the inferior posterior surface of the zygomatic process of the temporal bones. Anterior to the mandibular fossa is a rounded elevation called articular tubercle.
Temporal Bone The mandibular fossa and articular tubercle articulate with the mandible (lower jawbone) to form the temporomandibular joint (TMJ). Located posteriorly on the temporal bone is the mastoid portion. It is located posterior and inferior to the external auditory meatus or ear canal.
Temporal Bone The mastoid process is a rounded projection of the mastoid portion of the temporal bone posterior to the external auditory meatus. It is the point for several neck muscles attachment. The internal auditory meatus is the opening through which facial nerve (cranial nerve VII) and vestibulocochlear nerve (cranial nerve VIII) passes.
Temporal Bone The styloid process projects inferiorly from the inferior surface of the temporal bones and serve as a point of attachment for muscles and ligaments of the tongue a neck. Between the styloid process and mastoid process is the stylomastoid foramen.
Temporal Bone At the floor of the cranial cavity is the petrous portion of the temporal bone. This part is the triangular and it is located at the base of the skull between the sphenoid and occipital bones. The petrous portion houses the internal and middle ear, structure involve hearing and equibilirium.
Temporal Bone It also contain the carotid foramen, through which the carotid artery passes. Posterior to the carotid foramen and anterior to the occipital bone is the jugular foramen, passageway for the jugular vein.
Occipital Bone Forms the posterior part and most of the base of the cranium The foramen magnum is in the inferior part of the bone. Within this foramen, the medulla oblongata connect with the spinal cord. The vertebral and spinal arteries also pass through this foramen.
Occipital Bone The occipital condyles are oval processes with convex surface, one on either side of the foramen magnum. They articulates with depression on the 1st cervical vertebra (atlas) to form the atlanto- occipital joint. Superior to each occipital condyle on the inferior surface of the skull is the hypoglossal foramen.
Occipital Bone The external occipital protuberance is a prominent midline projection on the posterior surface of the bone just above the foramen magnum. A large fibrous, elastic ligament, the ligamentum nuchae, which help support the head, extend from the external occipital protuberance to the 7th cervical vertebra.
Occipital Bone Extending laterally from the protuberance are two curved ridges, the superior nuchal lines, and below these are two inferior nuchal lines, which is areas for the muscles attachment.
Sphenoid Bone Lies at the middle part of the base of the skull. Keystone of the cranial floor because it articulates with all the other cranial bones, holding them together Sphenoid articulation – joins anteriorly with the frontal bone, laterally with the temporal bones and posteriorly with the occipital bones.
Sphenoid Bone Lie posterior and slightly superior to the nasal cavity and forms part of the floor, side walls, and rear wall of the orbit. The shape of the sphenoid resembles a bat with outstretched wings. The body of the sphenoid is the cube-like medial portion between the ethmoid and occipital bones.
Figure 16.11 The sphenoid bone viewed from above.
Sphenoid Bone It contains the sphenoidal sinuses, which drain into the nasal cavity. The sella turcica, ia bony saddle-shaped structure on the superior surface of the body of the sphenoid. Anterior part of the sella turcica, which form the horn of the saddle, is a ridge called the tuberculum sellae.
Sphenoid Bone The seat of the saddle is a depression, called hypophyseal fossa, which contain pituitary gland. The posterior part of the sella turcica, which forms the back of the saddle, is another ridge called the dorsum sellae. The greater wings of the sphenoid project laterally from the body and form the anterolateral floor of the cranium.
Sphenoid Bone The greater wings also form part of the lateral wall of the skull just anterior to the temporal bone. The lesser wings, which are smaller, form a ridge of bone anterior and superior to the greater wings. They form part of the floor of the cranium and the posterior part of the orbit of the eye.
Sphenoid Bone Between the body and lesser wing, just anterior to the sella turcica is the optic foramen. Lateral to the body between the greater and lesser wings is a triangular slit called the superior orbital fissure. Pterygoid process – structures project inferiorly from the point where the body and wings unite and form the lateral posterior region of the nasal cavity. Some of the muscles that move the mandible attach to the pterygoid process.
Sphenoid Bone At the base of the pterygoid process in the greater wings is the foramen ovale. The foramen lacerum is bounded anteriorly by the sphenoid bone and medially by sphenoid and occipital bones Foramen rotundum – located at the junction of the anterior and medial parts of the sphenoid bone.
Ethmoid Bone Light, spongylike bone, located on the midline in the anterior part of the cranial floor medial to the orbits. Anterior to the sphenoid and posterior to the nasal bones
Ethmoid Bone Ethmoid bone forms: Part of the anterior portion of the cranial floor Medial wall of the orbit Superior portion of the nasal septum Most of the superior sidewalls of the nasal cavity.
Ethmoid Bone The lateral masses of the ethmoid bone compose most of the wall between the nasal cavity and orbits. Contain 3 to 18 air spaces, or “cells”. The ethmoidal cells together to form ethmoidal sinuses. The perpendicular plate forms the superior portion of the nasal septum
Ethmoid Bone The cribriform plate lies in the anterior floor of the cranium and forms the roof of the nasal cavity. The cribriform plate contain olfactory foramina through which axons of the olfactory nerve pass. Projecting upward from the cribriform plate is a triangular process called the crista galli. This structure is serve as a point of attachment for the membrane that cover the brain.
Figure 16.12 The right ethmoid bone and its related structures.
Ethmoid Bone The lateral masses of the ethmoid bone contain 2 thin, scroll shaped projection lateral to the nasal septum. These are the superior nasal conchae and middle nasal conchae. A third pair of conchae, the inferior nasal conchae, are separated bones.
Ethmoid Bone The conchae cause turbulance in inhaled air, which result in many inhaled particles striking and becoming trapped in the mucus that lines the nasal passageways. This turbulence thus cleanses the inhaled air before it passes into the rest of the respiratory tract. Turbulence airflow around the superior nasal conchae also aids in the distribution of olfactory stimulants for the sensation of smell. Air striking and mucous lining of the conhae is also warmed and moisted.
Nasal Bones Paired of the nasal bones meet at the midline Form part of the bridge of the nose The rest of the supporting tissue of the nose consists of cartilage
Maxillae A paired maxillae unite together to form the upper jawbone Articulate with every bone of the face except the mandible (lower jawbone) Forms part of the floor of the orbits, part of the lateral walls and floor of the nasal cavity, and most of the hard palate.
Maxillae The hard palate is a bony partition formed by palatine process of the maxillae and horizontal plates of the palatine bones that forms roof of the mouth. Each maxillae contains a large maxillary sinus that empties into the nasal cavity. The alveolar process of the maxillae is an arch that contain the alveoli (sockets) for the maxillary (upper) teeth.
Maxillae The palatine process is a horizontal projection of the maxillae that forms the anterior three quarters of the hard palate. The union and diffusion of the maxillary bones normally is completed before birth. The infraorbital foramen is an opening in the maxillae below the orbit. Inferior orbital fissure, located between the greater wing of the sphenoid and the maxilla.
Zygomatic Bones 2 zygomatic bones Called cheekbones Form the prominence of the cheek and part of the lateral wall and floor of each orbit Articulate with the maxillae and the frontal, sphenoid and temporal bones.
Lacrimal Bones In pair Smallest bones of the face Thin, resemble a fingernail in size and shape Posterior and lateral to nasal bones and form a part of medial wall of each orbit Contain lacrimal fossa, vertical tunnel formed with maxilla, that houses for the lacrimal sac. Lacrimal fossa – gathers tears and passes them into the nasal cavity.
Palatine Bones In pair L-shaped Form the posterior portion of the hard palate, part of the floor and lateral wall of the nasal cavity, and smallest portion of the floors of the orbits. The horizontal palate of the palatine bones form the posterior portion of the hard palate, which separate the nasal cavity and oral cavity
Inferior Nasal Conchae In pair Inferior to the middle nasal conchae of the ethmoid bone Scroll like bones that form a part of the inferior lateral wall of the nasal cavity and project into the nasal cavity. The inferior nasal conchae is a separate bones, they are not part of the ethmoid bone
Inferior Nasal Conchae All three pairs of the nasal conchae help swirl and filter air before it passes into the lungs. Only superior nasal conchae involve in the sense of smell
Vomer Triangular bone Located in the floor of the nasal cavity Articulates superiorly with perpendicular plate of the ethmoid bone and inferiorly with both the maxilla and palatine along the midline It is apart of the nasal septum, partition that divides the nasal cavity into right and left sides.
Mandible Lower jawbone Largest, strongest facial bone Movable skull bone Consist of a curved , horizontal portion, the body, and two perpendicular portions, the rami. The angle of the mandible is the area where each ramus meets the body
Mandible Each ramus has a posterior condylar process. On each condylar process has a articulating surface called mandibular condyle that articulates with the mandibular fossa and articular tubercle of the temporal bones. This articulation called temporomandibular joint (TMJ) Has anterior coronoid process to which temporalis muscles attaches. The depression between coronoid and condylar process called the mandibular notch
Mandible The alveolar process is an arch containing the alveoli (sockets) for the mandibular (lower) teeth. The mental foramen is located below the mandibular second premolar tooth. The mandibular foramen on the medial surface of each ramus. The mandibular foramen, beginning of the mandibular canal, which run obliquely in the ramus and anteriorly to the body deep to the roots of the teeth
Mandible The inferior alveolar nerves and blood vessels, which are distributed to the mandibular teeth, pass through this canal.
Hyoid Bone Single Unique, does not articulate with any bones Suspended from the styloid processes of the temporal bones by ligaments and muscles. Located in the anterior neck between the mandible and larynx Support the tongue, providing attachment sites for some tongue muscles and for muscles of the neck and pharynx.
Hyoid Bone Consists horizontal body and paired projection called the lesser horns and the greater horns. Muscles and ligaments attach to these paired projection.
The Important of Hyoid Bone It helps to support the tongue and serves as an attachment point for several muscles that help to elevate the larynx during swallowing and speech. The hyoid bone is unique in that it is the only bone of the body that does not articulate with any other bone. Instead, it is suspended above the larynx where it is anchored by ligaments to the styloid processes of the temporal bones of the skull. When depressed it also assists in locating vocal chords when intubating a patient
Paranasal Sinuses Cavities within certain cranial and facial bones and connecting with nasal cavity Lined with mucous membrane. Frontal, sphenoid, ethmoid and maxillary sinus.
Fontanels Soft spot – areas of unossified mesenchyme. Soon after birth it gradually become suture (intramembranous ossification) Anterior fontanel Posterior fontanel Anterolateral Posterolateral