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Skull notes

  1. 1. The Skull<br />Areas of Anatomy<br /><ul><li>Gross anatomy: part listing of the human body; studied by region or by system
  2. 2. Microscopic anatomy: histology
  3. 3. Developmental anatomy: embryology
  4. 4. Functional anatomy: physiology
  5. 5. Radiographic anatomy: study of the human body using x-rays
  6. 6. Anatomical position: body upright, with palms and hands facing forward, and feet close together
  7. 7. Body defining planes:
  8. 8. Coronal plane: passes from one side to another dividing the body into anterior and posterior parts
  9. 9. Sagittal plane: passes from front to back dividing the body into right and left parts. Mid-Sagittal is when the right and left parts are exactly equal, the dividing line passing in the middle
  10. 10. Transverse plane: passes from side to side and front to back horizontally dividing the body into superior and inferior parts
  11. 11. Relative anatomical terms:
  12. 12. Anterior = ventral = front
  13. 13. Posterior = dorsal = back
  14. 14. Superior = cephalic = upper
  15. 15. Inferior = caudal = lower
  16. 16. Proximal = closer to origin
  17. 17. Distal = away from origin
  18. 18. Superficial = close to surface
  19. 19. Deep = away from surface
  20. 20. Movement of body parts :
  21. 21. Extension = returning part to normal position
  22. 22. Flexion = bending body part ( forward movement of body part)
  23. 23. Abduction = moving part away from position; laterally
  24. 24. Adduction = moving part closer to body; medially
  25. 25. Rotation = along 1 axis, its either external (lateral) or internal (medial)
  26. 26. Circumduction = combined complex movement
  27. 27. Protrusion = forward movement of the mandible
  28. 28. Retraction = moving mandible back to its place
  29. 29. Basic body tissues and parts:
  30. 30. Tendons: fibrous connective tissue band which originates from the skeletal muscle and inserts into the bone.
  31. 31. Aponeurosis; fibrous connective tissue that forms a flat sheet. it lies between parts of the body
  32. 32. Fascia: a covering structure which surrounds and divides large spaces in the body to smaller compartments
  33. 33. Borsa: synovial structure that is found between, tendon-tendon, tendon-bone, it produces synovial fluid for lubrication</li></ul>Note: nerves are either sensory or motor or both<br />Body Systems: <br /><ul><li>Nervous system:
  34. 34. Central nervous system: brain and spinal cord
  35. 35. Nervous and endocrine systems are responsible for body function.Peripheral nervous system: cranial nerves (12 pairs arise from the brain), spinal nerves (31 pairs arise from spinal cord) and autonomic nervous system.</li></ul> Spinal cord: <br /><ul><li>Contains dorsal horn, which is located at the dorsal aspect. It is completely sensory
  36. 36. Contains ventral horn, located at the ventral aspect. It is completely motor
  37. 37. Dorsal root arises from dorsal horn while ventral root arises from ventral horn
  38. 38. Dorsal root passes through dorsal root ganglion, ventral root passes through ventral root ganglion
  39. 39. After passing through ganglia they form together spinal nerves
  40. 40. SensationGeneral Special PainVisionTouchTasteTempratureHearingPressureSmellingThey then divide into ventral and dorsal rami both being mixed
  41. 41. (Sensory and motor)
  42. 42. Mucoskeletal system : has 3 main components
  43. 43. Joints: where 2 or more bones come together
  44. 44. Bony joints: immovable (pelvis, sutures)
  45. 45. Relatively movable: fibrocartilage
  46. 46. Freely movable: synovial
  47. 47. Muscles: smooth, skeletal, cardiac
  48. 48. Skeletal: it is for movement, it is named based on
  49. 49. Function: extensor, abductor, etc
  50. 50. Shape: deltoid
  51. 51. Size: maximus, minimus
  52. 52. Attachment: temporalis
  53. 53. Length: short, long
  54. 54. Bones: 2 types
  55. 55. Axial skeleton: lies in the center (ex: pelvis)
  56. 56. Appendicular: has similar right and left parts
  57. 57. Bone is classified according to being:
  58. 58. Short
  59. 59. Long (ex: arm & forearm)
  60. 60. Flat (ex: skull)
  61. 61. Irregular (vertebrae)
  62. 62. Pneumatic: contains air cavities
  63. 63. Sesamoid: bone that lie in the tendon (ex: patella)</li></ul>Synovial Joints<br />Synovium is the membrane that produces the synovial fluid, it is important for lubrication and reduction of friction.<br />It is a weak structure, thus surrounded by fibrous joint capsule to prevent it’s separation during movement.<br />It is not necessary to have all the structures to achieve stabilityJoint stability is achieved by:<br /><ul><li>Joint capsule
  64. 64. Shape of the bone forming the joint
  65. 65. Ligaments
  66. 66. Muscles around the joint</li></ul>The skull is part of the axial skeleton <br />It is composed of 22 bones:<br /><ul><li>21 firmly joined together by sutures
  67. 67. Mandible: a single movable bone which articulates with the skull at the TMJ (a synovial joint)</li></ul>Note:The hard palate is formed by the Maxillary bones (anterior 1/3) and the palatine bones (posterior 2/3)The 22 bones are either single or paired (one on each side)<br />6 Single Bones8 Paired BonesMandibleMaxillaryFrontal NasalOccipitalZygomaticSphenoidInferior Nasal conchaeEthmoidParietal VomerTemporalLacrimal Palatine <br />Bones are either facial or cranial<br />Views of the Skull<br />Outside views<br />Superior <br />Inferior = Basal<br />Posterior = occipital<br />Anterior = Frontal<br />Lateral = Temporal<br /><ul><li>Anterior View: frontal
  68. 68. Bones present in this view are: frontal, nasal, lacrimal, maxillary, mandibular, zygomatic, vomer, inferior conchae
  69. 69. Frontal bone: convex in shape, forms forehead
  70. 70. Orbit: opening of the eyes. Has 4 orbital margins
  71. 71. Supraorbital margin: formed by frontal bone
  72. 72. Medial orbital margin: formed by fontal (superiorly), maxilla (inferiorly)
  73. 73. Infraorbital: formed by zygoma, and maxilla
  74. 74. Lateral orbital margin: frontal (superiorly), zygomatic (inferiorly)
  75. 75. Landmarks of the orbit:
  76. 76. Supraorbital notch/foramen: in the superior orbital margin for transmission of vessels and nerves. Painful if pressed on
  77. 77. Superciliary arch: a bony elevation lying above the supraorbital margin. (eyebrows lie exactly above the margin)
  78. 78. Glabella: hairless region between the supraciliary arches. Clinical significance: 1- skin turgidity can be measured in patients suspected of dehydration. 2- glabellar reflex, in which a person’s forehead is taped several time and the subject blinks, if the blinking persists, which is called Myerson’s sign, being an early symptom of Parkinson’s disease, dementia and neurological disorders
  79. 79. Nasion: root of the nose, depressed area between the 2 orbits
  80. 80. Infra-orbital foramen: located in the anterior surface of the maxilla on the same line vertically with the supra-orbital foramen
  81. 81. Anterior nasal apertures: (nasal openings), their boundaries are the 2 nasal bones superiorly, maxillary bone laterally, maxillary bone inferiorly
  82. 82. Zygoma: 2 bones below the orbit
  83. 83. Inferior and middle nasal conchae (superior are hidden and not seen in frontal view)
  84. 84. Superior and middle nasal conchae are part of the ethmoid but the inferior nasal concha is a separate bone
  85. 85. Alveolar processes
  86. 86. Of the maxilla, have sockets that carry the maxillary teeth
  87. 87. Of the mandible, containing sockets for the mandibular teeth</li></ul>171450318770<br /><ul><li>Lateral View: also called the temporal view
  88. 88. Landmarks of the lateral view:
  89. 89. Anterior nasal spine: union of 2 maxillary bones at the lower border or the anterior nasal apertures
  90. 90. Nasal septum: divides nasal cavity vertically into 2 cavities
  91. 91. nasal septum is divided into 3 parts: anteriorly nasal cartilage, inferiorly vomer, superiorly perpendicular plate of the ethmoid.
  92. 92. Lateral orbital margin
  93. 93. Temporal lines: they are either superior and inferior or one single line
  94. 94. Zygomatic arch: formed by the zygomatic process of temporal bone and the temporal process of the zygomatic bone
  95. 95. Temporal fossa:
  96. 96. Region limited by temporal lines superiorly and zygomatic arch inferiorly
  97. 97. 323850246380Formed by: frontal, parietal, greater wing of sphenoid and temporal bones
  98. 98. Gives rise to temporalis muscle
  99. 99. Pterion:
  100. 100. H-shaped region
  101. 101. Lies above anterior branch of middle meningeal artery
  102. 102. Very thin bone, easily fractured leading to injury of underlying artery which will result in intercranial, epidural or extradural hematoma. May compress the brain tissue
  103. 103. External acoustic meatus: auditory tube, posterior to the TMJ
  104. 104. Mastoid process:
  105. 105. Conical bony projection behind ear, pulpable area
  106. 106. Contain air filled cells, function in?????
  107. 107. Provides attachment to muscles and ligaments???????
  108. 108. Styloid process: deep, not pulpable, attaches muscles and ligaments (styloid apparatus)
  109. 109. Paranasal air sinuses: air filled cavities which open into the nose
  110. 110. Frontal
  111. 111. Maxillary
  112. 112. Sphenoid
  113. 113. Ethmoid
  114. 114. Superior View: calvaria</li></ul> Bones present are: frontal bone, right and left parietal bones, occipital bone<br /> Landmarks:<br /><ul><li>Coronal suture: between frontal bone and the 2 parietal bones
  115. 115. Sagittal suture: between the 2 parietal bones
  116. 116. Lambdoid suture: between the 2 parietal and the occipital bones
  117. 117. Bregma : meeting point of coronal and sagittal sutures
  118. 118. Lambda: meeting point of lambdoid and sagittal sutures
  119. 119. Parietal foramen: in the parietal bones, for transmission of emissary veins (veins which connect venous blood from the outside to the inside)</li></ul> Neonatal skull:<br /><ul><li>Sutures are not well joined together
  120. 120. Sagittal suture looks like an arrow
  121. 121. Metopic suture: lies between the 2 frontal bones and ossifies by the age of 5
  122. 122. Anterior fontanelle: unossified “bregma”, ossifies by the age of 18 month to form bregma
  123. 123. Posterior fontanelle: unossified “lambda”, ossifies by the age of 9 month to form lambda
  124. 124. They function to assess the intercranial pressure by palpation (bulge if high and depress if low pressure)</li></ul>171450-455295<br /><ul><li>Posterior view:
  125. 125. Landmarks of the posterior view:
  126. 126. Sagittal Suture
  127. 127. Lambdoid Suture
  128. 128. External Occipital protuberance: a projection in the squamous part of the occipital bone
  129. 129. Nuchal lines: superior and inferior extending from the lateral part of the external occipital protuberance
  130. 130. Temporal Bone
  131. 131. Parietal Bone
  132. 132. Occipital Bone
  133. 133. Maxillary Bone
  134. 134. Mandibular Bone</li></ul>45720-36195<br /><ul><li>Inferior view:
  135. 135. 12 pairs of cranial nerves which pass through the openings in the inferior view
  136. 136. Olfactory
  137. 137. Optic
  138. 138. Occulomotor
  139. 139. Trochlear
  140. 140. Muscles of mastication:TemporalisMasseterMedial pterygoidLateral pterygoid Abducent
  141. 141. Trigeminal
  142. 142. V1 ophthalmic
  143. 143. V2 Maxillary
  144. 144. V3 Mandibular
  145. 145. Facial
  146. 146. Vestibulochoclear
  147. 147. Glossopharyngeal
  148. 148. Vagus
  149. 149. Accessory
  150. 150. Hypoglossal
  151. 151. Landmarks of the inferior view:
  152. 152. U-Shaped maxilla
  153. 153. Hard palate: separates oral from nasal cavity, anterior 2/3 formed by maxilla, posterior 1/3 formed by the horizontal plate of the palatine bone
  154. 154. Palatine process of the maxilla
  155. 155. Sphenoid bone
  156. 156. Greater wing
  157. 157. Lesser wing
  158. 158. Medial and lateral pterygoid processes
  159. 159. Body of the sphenoid
  160. 160. Pterygoid fossa: lies between the medial and lateral pterygoid processes and gives attachment to pterygoid muscles
  161. 161. Infratemporal fossa: exposed by removal of the zygomatic arch and the mandible, it’s boundaries are:
  162. 162. Anteriorly: maxilla
  163. 163. Posteriorly: styloid process
  164. 164. Laterally: zygomatic arch or ramus of the mandible
  165. 165. Medially: lateral pterygoid plate
  166. 166. Posterior nasal openings: nasal choanae, communicates the nasal cavity to the oropharynx it’s boundaries are:
  167. 167. Superiorly: body of the sphenoid
  168. 168. Inferiorly: horizontal plates of the palatine bone
  169. 169. Medially: vomer
  170. 170. Laterally: medial pterygoid processes
  171. 171. Temporal bone:
  172. 172. Zygomatic process
  173. 173. Squamous part
  174. 174. Petrous part
  175. 175. Styloid process
  176. 176. Mastoid process
  177. 177. Tympanic plate </li></ul>552450-398145<br /><ul><li>Cranial base of the skull:
  178. 178. Contains several openings and foramina through which the nerves and blood vessels pass
  179. 179. Occipital condyle: bony mass on each side of foramen magnum and articulates with atlas (C1) to form atlantooccipital joint
  180. 180. OpeningpositionStructures passing throughCribriform platePart of the Ethmoid boneOlfactory bulb/fibers (from olfactory nerve I)Optic canalAt root of lesser wingOptic nerve IIOphthalmic artery Supraorbital fissureCommunicates the orbital canal and middle cranial fossa, between lesser and greater wings of sphenoidOculomotor nerve IIITrochlear nerve IVOphthalmic nerve V1Abducent VISuperior and inferior ophthalmic veinsForamen Rotundum In greater wing of sphenoid, communicates middle cranial fossa with pterygopalatine fossaMaxillary nerve V2Foramen Ovale In greater wing of sphenoid , communicates middle cranial to Infratemporal fossaMandibular nerve V3Foramen lacerumBetween body of the sphenoid and Petrous part of temporal boneGreater Petrosal nerve (a branch of the facial nerve VII, which then leaves through the stylomastoid foramen)Foramen spinosumIn greater wing of the sphenoid, communicates middle cranial fossa to Infratemporal fossaAnterior branch of the middle meningeal arteryCarotid canalIn Petrosal part of temporal bone, opens into posterior wall of foramen lacerumInternal carotid arterySympathetic nerve plexusInternal acoustic meatusIntracranially, in the posterior surface of the Petrous part of the temporal boneFacial nerve VIIVestibulocochlear nerve VIIIStylomastoid foramenBetween styloid and mastoid processes of the temporal boneFacial nerve VII (pure motor branch)Jugular foramenBetween occipital bone and Petrous part of temporal boneGlossopharyngeal IXVagus nerve XAccessory nerve XIInternal jugular veinsSigmoid sinusPosterior meningeal arteryInferior Petrosal venous sinusCondylar canalAnterior to occipital condyleEmissary veinsHypoglossal canalPosterior to condyleHypoglossal nerve XIIForamen magnumOccipital boneSpinal root and its covering meningesSpinal root accessoriesVertebral artery</li></ul>The spinal root arises from the spinal cord then enters the skull through foramen magnum to join with the cranial root and leave jugular foramen as accessory nerveVertebral arteries supply posterior part of the brain<br />266700-302895<br />Cranial Fossae<br /><ul><li>Anterior cranial fossa:
  181. 181. Boundaries: from Squamous part of the frontal bone to the lesser wing of the sphenoid
  182. 182. Contents: frontal lobes of brain
  183. 183. Floor is formed by:
  184. 184. Cribriform plate of the Ethmoid bone , it lies between the nasal cavity and the anterior cranial fossa (part of floor of ACF and roof or nasal cavity)
  185. 185. Crista galli: upward bony projection (from cribriform plate) which attaches to falx cerebri
  186. 186. Orbital plate of frontal bone
  187. 187.
  188. 188. Middle cranial fossa:
  189. 189. Boundaries: lesser wing of sphenoid anteriorly to petrous part of temporal bone posteriorly
  190. 190. It is composed of 2 lateral portions, a central portion formed by superior surface of the body of the sphenoid
  191. 191. The central portion includes sella turcica (also called the hypophyseal fossa or pituitary fossa). Tuberculum sellae: anterior limit of sella turcice. Dorsum sellae: posterior limit of sella turcica
  192. 192. Floor:
  193. 193. Greater wing and body of sphenoid
  194. 194. Squamous part of temporal bone
  195. 195. Part of Petrous part of temporal bone
  196. 196. Posterior cranial fossa:
  197. 197. Boundaries: upper border of Petrous part of temporal bone anteriorly and Squamous part of occipital bone Posteriorly
  198. 198. Contains: the cerebellum
  199. 199. Landmarks:
  200. 200. Internal occipital protuberance: projection in the inner surface opposite to the external occipital protuberance
  201. 201. Sigmoid sulcus: S-shaped sulcus, contains the sigmoid venous sinus
  202. 202. Before the facial nerve enters the internal acoustic meatus, it gives a branch to the greater petrosal nerve, which then leaves through foramen lacerum. The facial nerve leaves the Stylomastoid foramen as pure motorSulcus for Transverse Sinus: contains the transverse venous sinus</li></ul>Facial Stylomastoid foramenForamen lacerumGreat petrosalIAMFacial nerve<br />Meninges<br />They are 3 membranes which surround the brain and spinal cord.<br /><ul><li>Pia mater: delicate layer directly attached to the brain and spinal cord
  203. 203. Subarachnoid space: space that lies between the Arachnoid mater and the Pia mater. Contains CSF (cerebrospinal fluid) which act as a cushion to protect the brain and spinal cord
  204. 204. Arachnoid mater: transparent layer, which lies over the Pia mater. It shows trabeculations (arachnoid granulation villi), which function in the drainage of the CSF and the venous blood in the venous sinuses
  205. 205. Subdural Space: contains blood vessels
  206. 206. Dura mater: tough layer which lies over the Arachnoid mater
  207. 207. Cranial dura: consists of periosteal layer (endosteal layer) which is the lining of the skull bone, and the real dura mater, which is the tough fibrous layer
  208. 208. Epidural Space: lies between dura mater and bone. Contains blood vessels</li></ul>250825-650875<br />Dura Mater<br />The Dura mater is separated into 2 layers called the dural folds or projections, they separate different brain hemispheres.<br /><ul><li>Falx Cerebri:
  209. 209. separates the 2 cerebral hemispheres
  210. 210. Double layer of dura which separate the 2 cerebral hemispheres
  211. 211. Attached anteriorly to crista galli
  212. 212. It has 2 borders:
  213. 213. Upper: superior Sagittal sinus lies in it
  214. 214. Lower border: inferior Sagittal sinus lies in it
  215. 215. Falx Cerebelli:
  216. 216. separates the 2 cerebellar hamispheres
  217. 217. Tentorium Cerebelli:
  218. 218. separates the cerebellum from the occipital lobes of the cerebrum
  219. 219. Forms a tent over the posterior cranial fossa
  220. 220. Diaphragm Selli:
  221. 221. Very small dural projection that form the roof of sella turcica
  222. 222. Has an opening in the middle for the stalk of the pituitary gland</li></ul>Dural Venous Sinuses<br />Venous channels which lie between the 2 layers of the Dura mater. They lack valves and smooth muscles in their walls, as blood flows with gravity.<br />Single SinusesPaired Sinuses<br />Superior Sagittal Venous SinusTransverse Venous Sinus<br />Inferior Sagittal Venous SinusSigmoid Venous Sinus<br />Straight SinusCavernous Venous Sinus<br />Superior Petrosal Sinus<br />Inferior Petrosal Venous Sinus<br />Single Sinuses<br /><ul><li>Superior Sagittal venous sinus:
  223. 223. In the upper border of the falx cerebri
  224. 224. Runs upwards and backwards ending at the internal occipital protuberance
  225. 225. Inferior sagittal venous sinus:
  226. 226. In the lower border of the falx cerebri
  227. 227. Joins with the great cerebral vein to form the straight sinus, which runs upwards and medially
  228. 228. Straight Sinus:
  229. 229. Formed by the union of the great cerebral vein and the inferior petrosal venous sinus
  230. 230. Runs at the meeting point of the tentorium cerebella and falx cerebri
  231. 231. Ends at the internal occipital protuberance
  232. 232. Paired Sinuses
  233. 233. Transverse Sinus:
  234. 234. Right transverse sinus: continuation of the superior Sagittal sinus
  235. 235. Left transverse sinus: continuation of the straight sinus
  236. 236. Passes lateral to the internal occipital protuberance on both sides
  237. 237. Sigmoid Sinus:
  238. 238. 247650-798195Continuation of the transverse sinus
  239. 239. Ends at the jugular foramen forming the jugular bulb which then continues as internal jugular vein
  240. 240. Cavernous Sinus:
  241. 241. Cave like, lies in body of the sphenoid
  242. 242. It has a special importance as some important structures pass through it
  243. 243. Vessels: internal carotid artery
  244. 244. Nerves: Occulomotor III, Trochlear IV, Abducens VI, V1 & V2 of trigeminal V
  245. 245. 3714750358775Infection in the dangerous zone (angle between mouth and eye) can easily transmit it into the brain by the following pathway:
  246. 246. Facial Vein pterygoid venous plexus inferior ophthalmic vein cavernous sinus
  247. 247. Any problem in the cavernous sinus affects movement of eyeball, sensation of the face, blood supply to the brain
  248. 248. Cavernous sinus receives blood from superior and inferior ophthalmic vein. Before entering the sinus, the inferior ophthalmic vein communicates with the pterygoid plexus
  249. 249. Superior petrosal sinus:
  250. 250. Arises from the upper posterior part of the cavernous sinus
  251. 251. Runs in the upper border of the petrous part of the temporal bone, to joining the sigmoid venous sinus
  252. 252. Inferior petrosal sinus
  253. 253. Arises from lower part of cavernous sinus
  254. 254. Joins internal jugular vein, from outside the skull after passing through the jugular foramen
  255. 255. 247650228600It’s the only venous sinus that leaves the skull with the venous blood</li></ul>Individual Bones of the Skull<br />1) Maxilla: a paired bone which has 4 processes and 4 surfaces<br /><ul><li>4 surfaces :
  256. 256. Superior: it separates the orbital cavity from the maxillary air sinuses
  257. 257. Anterior: facial
  258. 258. Posterior: forms anterior limit of infratemporal fossa
  259. 259. Medial (nasal): forms lateral wall of the nasal cavity
  260. 260. 4 processes:
  261. 261. Frontal: joins the frontal bone to form the medial orbital margin
  262. 262. Zygomatic: joins the zygoma to form the infra orbital margin
  263. 263. Alveolar: Contains sockets for upper teeth
  264. 264. Palatine: joins palatine bone to form the hard palate
  265. 265. Articulations of the maxilla: frontal, nasal, zygomatic, inferior nasal concha, palatine bone, ethmoid, maxilla
  266. 266. Maxillary nasal sinuses are located in the medial (nasal) process. It is one of the biggest sinuses and functions in resonance of voice and lightening of weight of skull
  267. 267. 94869037465
  268. 268. Mandible: A single bone, horseshoe shaped, which is composed of a body and 2 rami
  269. 269. The body: composed of 2 surfaces (inner and outer) and 2 borders (superior and inferior)
  270. 270. Outer surface:
  271. 271. Mental protuberance: lies in the midline
  272. 272. Mental tubercle: lies on both sides of the protuberance
  273. 273. Mental foramina: located below the apices of the premolar-molar. Can be used to determine the age of a person as it is closer to the inferior border in infants and closer to the superior border in elderly people, in adults it lies in the middle. (the change in position is relative as the bone is not completely grown in infants and is resorbed in elderly)
  274. 274. Oblique line: also called the external oblique ridge, extends from mental foramen to the anterior border of the ramus
  275. 275. 403860105410
  276. 276. Inner surface:
  277. 277. Superior and inferior mental spines (genial tubercles): 4 projections which lie in the midline which give attachment to:
  278. 278. Superior: genioglossus muscle
  279. 279. Inferior: geniohyoid muscle
  280. 280. Mylohyoid line: gives attachment to mylohyoid muscles which are 2 muscles join to form the floor of the mouth
  281. 281. Sublingual fossa: a depression which lies above the mylohyoid line. Contains the sublingual salivary glands
  282. 282. Submandibular fossa: a depression which lies below the mylohyoid line. Contains the submandibular salivary gland
  283. 283. 257175294005Digastric fossa: located below the genial tubercle
  284. 284. The Ramus: each has 2 surfaces(medial and lateral),2 processes (anterior/coronoid and posterior/condylar) and 2 borders (anterior and posterior)
  285. 285. Ramus meets the body to form the angle of the ramus
  286. 286. Surfaces:
  287. 287. Lateral: smooth except where it gives attachment to the massetter muscle
  288. 288. Medial surface:
  289. 289. The ramus is sandwiched by the massetter muscle from outside and medial pterygoid from the insideMandibular foramen: opens to the mandibular canal which ends at the mental foramen, transmitting the inferior alveolar nerve and blood vessels. Mental nerve is the continuation of the inferior alveolar nerve, supplies lower teeth and lip, thus anesthesia is given in it.
  290. 290. Lingula: bony projection, lies anterior to mandibular foramen. Provides attachment to ligaments.
  291. 291. Rough region in the lower part of inner surface, gives attachment to the medial pterygoid muscle.
  292. 292. Processes:
  293. 293. Coronoid/anterior: gives attachment to temporalis
  294. 294. Condyle/posterior:
  295. 295. Head: articulates with mandibular fossa of temporal bone forming TMJ
  296. 296. Neck : provides attachment to capsule of TMJ
  297. 297. Sphenoid Bone: a single bone has the shape of a butterfly.
  298. 298. It is composed of:
  299. 299. Body
  300. 300. 2 greater wings
  301. 301. 2 lesser wings
  302. 302. 2 pterygoid processes
  303. 303. Body:
  304. 304. Has 2 surfaces:
  305. 305. Superior: forms sella turcica/pituitary fossa/
  306. 306. Inferior: forms upper margin of coanae and upper border of pharynx
  307. 307. Sphenoid air sinuses:
  308. 308. Upper border: sella turcica
  309. 309. Lower border: roof of pharynx
  310. 310. Visible in the anterior view
  311. 311. Greater wing of sphenoid:
  312. 312. Has 4 surfaces:
  313. 313. Cranial surface
  314. 314. Lateral surface: temporal
  315. 315. Inferior : infratemporal , roof of infratemporal fossa
  316. 316. orbital
  317. 317. Between the lesser and greater wings lies the superior orbital fissure
  318. 318. Pterygoid plates/processes:
  319. 319. Medial and lateral processes/plates in between them lies the pterygoid fossa
  320. 320. The pterygoid fossa provides attachment to the medial and lateral pterygoid muscles
  321. 321. The pterygoid fossa can be seen only in the posterior view
  322. 322. Optical canal is located at the roof of lesser wing and above superior orbital fissure, while rotundum is below superior orbital fissure
  323. 323. Above the pterygoid plate lies the pterygoid canal (transmits the pterygoid nerve)
  324. 324. Ovale, rotundum and spinosum are present on the greater wing but are not visible in the anterior or posterior view.
  325. 325. Articulations of the sphenoid bone:
  326. 326. Palatine bone, ethmoid, nasal bone, temporal , vomer, frontal, parietal, occipital, zygoma, maxilla
  327. 327. 88392029940252945130107950-895350107950
  328. 328. Ethmoid: single bone, lies between the 2 orbits
  329. 329. it is also located in:
  330. 330. To differentiate between medial and lateral views of the nasal cavity: in the medial view the septum is presentupper part of nasal cavity
  331. 331. roof of nasal cavity
  332. 332. perpendicular plate of the ethmoid, forms part of the nasal septum
  333. 333. lateral wall of ethmoid forms the medial wall of the orbit
  334. 334. medial wall of the ethmoid forms the lateral wall of the nasal cavity
  335. 335. the labyrinth contains air filled cavities (ethmoidal air cells), each has
  336. 336. medial/ nasal plate
  337. 337. has 2 projections: superior and middle nasal conchae
  338. 338. lateral/orbital plate
  339. 339. 2800350234950-895350234950cribriform plate separates the nasal cavity from the anterior cranial fossa
  340. 340. 276225-86360
  341. 341. Frontal Bone: single bone, developed from 2 halves, which are separated by the metopic suture (ossifies at the age of 5 years)
  342. 342. It is composed of 2 processes:
  343. 343. Maxillary: articulates with the maxilla to form medial orbital margin
  344. 344. Zygomatic: articulates with the zygoma to form lateral orbital margin
  345. 345. In the upper orbital margin lies the supraorbital foramen/notch
  346. 346. Supraciliary arch: lies above the supraorbital margin (below the eyebrow)
  347. 347. Glabella: hairless area between the supraciliary arches
  348. 348. Frontal nasal sinuses: 2, which drain the nasal cavity
  349. 349. They are lined by the same epithelium of the nasal cavity
  350. 350. They function in:
  351. 351. Weight reduction
  352. 352. Sound resonance
  353. 353. Squamous part:
  354. 354. Forms the vault and forehead
  355. 355. Forms the floor of the anterior cranial fossa
  356. 356. Forms the roof of the orbital cavity
  357. 357. Foramen cecum: lies anterior to crista galli, for transmission of emissary veins
  358. 358. Temporal Bone: paired bone, on the lateral sides of the skull, composed of 5 parts
  359. 359. Squamous, petrous, mastoid, styloid, tympanic
  360. 360. Squamous:
  361. 361. Vertical flat part
  362. 362. Forms part of the floor of the temporal fossa
  363. 363. Has the zygomatic process which articulates with the zygoma to form the zygomatic arch
  364. 364. Mandibular fossa: inferior to zygomatic process. Site of articulation with the condyle
  365. 365. Tympanic plate:
  366. 366. Chorda tympani exits between the tegmen tympani and anterior edge of tympanic plateAnterior limit of external acoustic meatus
  367. 367. Mastoid process:
  368. 368. Conical, palpable bony projection, lies behind the ear
  369. 369. Contains air filled cavities (mastoid air cells)
  370. 370. For resonance of sound
  371. 371. Gives attachment to sternocleidomastoid muscle and posterior belly of Digastric muscle
  372. 372. Gives attachment to ligaments
  373. 373. Styloid process:
  374. 374. Deeply seated, non-palpable
  375. 375. This downwardly projected bony process
  376. 376. Gives attachment to:
  377. 377. Stylohyoid muscle
  378. 378. Stylopharyngeal muscle
  379. 379. Styloglossus muscle
  380. 380. Stylohyoid ligament
  381. 381. Stylomastoid foramen lies between the styloid and mastoid processes
  382. 382. Petrous part:
  383. 383. Sometimes called petromastoid (closely related to mastoid)
  384. 384. Hard rock like bony part containing important structures
  385. 385. Ear cavity (through internal acoustic meatus)
  386. 386. Carotid canal (transmits internal carotid artery and sympathetic plexus)
  387. 387. Facial nerve
  388. 388. -8953502660652814320178435Vestibulocochlear nerve
  389. 389. Occipital bone: single flat bone, forms posterior part of the skull and part of the base of the skull
  390. 390. Squamous part: The curved, expanded plate behind the foramen magnum
  391. 391. Superior and inferior nuchal lines which project laterally from the external occipital protuberance
  392. 392. Internal occipital crest: projection which lies posterior to the foramen magnum (internally)
  393. 393. Internal occipital protuberance (internally)
  394. 394. Has transverse groove for transverse sinus (internally)
  395. 395. Basilar part: the thick part in front of the foramen magnum,
  396. 396. Projects anteriorly, forming part of the roof of the pharynx (pharyngeal tubercle)
  397. 397. 2746484281261-895350281261Articulates with part of the sphenoid
  398. 398. 2837180100965
  399. 399. Nasal bone: a paired bone
  400. 400. Join in the midline forming part of the roof of the nasal cavity
  401. 401. Zygomatic bone: paired bone, forms the prominence of the cheek
  402. 402. 2651760193040-548640193040Articulates with frontal, maxillary, greater wings of sphenoid and temporal bone
  403. 403. Lacrimal bone: paired bone
  404. 404. Forms part of the medial wall of the orbit
  405. 405. 3313430403860-186055403860Nasolacrimal duct: a canal that connects the orbit to the nasal cavity (for the drainage of tears)
  406. 406. Palatine bone: paired bone, L-shaped
  407. 407. 2 plates:
  408. 408. Horizontal: forms the posterior third of the hard palate and the projecting nasal crest forms part of the nasal septum
  409. 409. -857250597535Perpendicular plate: forms lateral wall of the nasal cavity
  410. 410. 2493645196215
  411. 411. Inferior nasal conchae: paired bones
  412. 412. Attached to lateral wall of the nasal cavity
  413. 413. A fragile bone
  414. 414. Increases surface area of nasal cavity
  415. 415. Lined by mucous membrane
  416. 416. 315595092075Vomer: single bone, a thin deep plate
  417. 417. Articulates with
  418. 418. Nasal septum: vomer, septal cartilage, perpendicular plate of the ethmoidMaxilla
  419. 419. Ethmoid
  420. 420. Sphenoid
  421. 421. Septal cartilage (inferiorly) </li></ul>Face<br />The face extends from the hair to the lower border of the mandible and from the ear to the ear<br />Contents of the face:<br /><ul><li>Skin: includes hair follicles, sweat glands and sebaceous glands
  422. 422. Connective tissue: has superficial fascia only, no deep fascia
  423. 423. Muscles: mastication and facial expression muscles
  424. 424. Blood Vessels: arteries and veins
  425. 425. Glands: parotid and submandibular glands
  426. 426. Nerves: trigeminal and facial nerves</li></ul>Muscles of facial expression:<br /><ul><li>Responsible for expression
  427. 427. Control size of facial openings (each has sphincter/closes
  428. 428. Mouth
  429. 429. Nose
  430. 430. eyes
  431. 431. Arise from facial skeleton and are inserted into skin
  432. 432. Arise from 2nd branchial arch
  433. 433. Supplied by facial nerve</li></ul>Muscles of the Eyes:<br />Name of MuscleSphincter/DilatorFunctionOrbicularis oculiPeripheral/orbital partCentral/palpebral partsphincterWhole muscle: helps move tears towards midline of faceOrbital part: forceful closurePalpebral part:gentle closureFrontalisDilatorElevates eyebrows, and wrinkles forehead, opens the eyeLevator palpebrae superiorisDilatorElevates upper eyelid, only muscle supplied by the occulomotor nerve<br />Muscles of the nostrils:<br />Name of MuscleSphincter/dilatorFunctionDilator narisDilatorDilates opening of noseCompressor narisSphincterCloses opening of nose<br />Muscles of the Mouth: <br />Name of muscleSphincter/dilatorfunctionOrbicularis orisSphincterArises from the maxilla and mandible, brings the 2 lips together (whistling action)Zygomaticus major and minorDilator Elevates the angel of the mouthLevator labii superiorisDilatorElevates the upper lip upwardsLevator anguli orisDilatorLies between the zygomaticus major and minor, elevates angel of mouthDepressor labii inferiorisDilatorMoves lip downwardsDepressor anguli orisDilatorMoves angel of mouth downwardsMentalisDilatorDepressing of chinResoriusDilatorMoves angle of mouth horizontallyPlatysmaDilatorDepression of lower lip, tightening of the skin of the neck<br />-35560197485<br />Muscles of the Cheek:<br /> Buccinator Muscle: lie between massetter and angel of mouth<br /><ul><li>Anterior fibers mix with orbicularis oris muscle
  434. 434. Pierced by the duct of the parotid gland
  435. 435. Function
  436. 436. Blowing
  437. 437. Pushing food out of the vestibule into the oral cavity proper</li></ul>Blood Supply of the Face<br /><ul><li>Maxillary ArteryArterial blood supplySupraorbital ArterySupratrochlear ArteryOphthalmic ArteryMental ArteryInfraorbital ArteryFacial ArterySuperficial Temporal ArteryInternal CarotidExternal Carotid ArteryCommon Carotid Artery:
  438. 438. External and Internal Jugular VeinsRetromandibular VeinSuperficial Temporal VeinFacial VeinVenous drainage: </li></ul>Nerve Supply of the face<br />Sensory for the skin<br />Motor for the muscles<br />Trigeminal Nerve VSensory Supply:<br />Mandibular Division V3Ophthalmic division V1Maxillary Division V2<br />Skin of the face from the angle of the eye upwards. Upper eyelid skin, anterior and lateral parts of the nose, foreheadFrom angle of the eye to the angle of the mouth. Lower eyelid, skin of cheeks, upper lipAngle of the mouth downwards. Parotid region, lower lip, chin, lateral side of the scalp<br />Motor Supply:<br />1957032449921All muscles of facial expression are supplied by the facial nerve (VII) except the levator palpebrae superioris muscle which is supplied by the occulomotor nerve (III)<br />Facial Nerve gives 5 motor branches:<br /><ul><li>Temporal
  439. 439. Zygomatic
  440. 440. Buccal
  441. 441. Mandibular
  442. 442. cervical</li></ul>Facial Palsy: damage to the facial nerve<br />It leads to:<br /><ul><li>paralysis to ½ of the face
  443. 443. inability to whistle
  444. 444. inability to close eyes leading
  445. 445. To dry and ulcerated cornea
  446. 446. inability to blow
  447. 447. angle of mouth droops causing saliva to come out
  448. 448. face will shift towards normal side</li></ul>Parotid Region<br />It is the area in the side of the face inferior and anterior to the ear<br /><ul><li>salivary glands in the parotid region are:
  449. 449. parotid: the largest salivary gland
  450. 450. submandibular
  451. 451. sublingual
  452. 452. scattered small salivary glands in the submucosa of the cheeks
  453. 453. saliva is either
  454. 454. serous (water like)
  455. 455. mucous (thicker)
  456. 456. it helps in digestion, turning food into a bolus thus making swallowing easier and also helps in speech
  457. 457. parotid salivary glands:
  458. 458. 1 on each side: wedge shaped, exocrine gland
  459. 459. It has 3 surfaces:
  460. 460. Anteromedial surface: faces the massetter muscle, medial pterygoid muscle and ramus of mandible
  461. 461. Posteromedial surface: faces the mastoid process and sternocleidomastoid muscle
  462. 462. Lateral surface: faces the skin and great auricular nerve
  463. 463. Surrounded by parotid capsule which is a continuation of the investing layer of the deep fascia
  464. 464. 3195320715010Stansen’s duct: the opening of the parotid gland. Starts from the anterior border of the gland and then passes through the massetter and turns medially to pierce the buccinator muscle then pens into the vestibule opposite to the upper second molar
  465. 465. Structures that pass within the parotid gland:
  466. 466. Facial nerve
  467. 467. Retromandibular vein
  468. 468. External carotid artery
  469. 469. Auriculotemporal nerve</li></ul>Facial Nerve: enters the parotid gland without supplying it from the posteromedial surface, dividing it into a deep lobe and a superficial lobe. It ends within the parotid gland giving five terminal motor branches (temporal, zygomatic, Buccal mandibular, cervical)<br />Structures passing into the parotid gland: <br /><ul><li>Veins
  470. 470. Superficial vein and maxillary vein join into the gland to form the retromandibular vein.
  471. 471. The retromandibular vein then divides into anterior and posterior divisions
  472. 472. The anterior division joins the facial vein to form the common facial vein which extends as the internal jugular vein
  473. 473. Facial Common FacialRetromandibularSuperficial temporalThe posterior division joins the great auricular vein to form the external jugular vein</li></ul>Parotid gland<br />Internal jugularAnt. division<br />Maxillary <br />External jugularGreat auricularPosterior division<br /><ul><li>Arteries:
  474. 474. External carotid enters the gland and ends in it by giving superficial temporal artery and maxillary artery</li></ul>Nerve Supply of the gland<br /><ul><li>Sensory:
  475. 475. by auriculotemporal nerve which is branch of V3
  476. 476. carries pain sensation from the capsule of the parotid gland
  477. 477. Autonomic:
  478. 478. Sympathetic:
  479. 479. By sympathetic plexus surrounding external carotid artery
  480. 480. Decreases salivation and secretions (dry mouth)
  481. 481. Parasympathetic
  482. 482. By glossopharyngeal carried by the lesser petrosal nerve
  483. 483. The salivary nuclei located in the brain is responsible for the production of saliva
  484. 484. The preganglionic parasympathetic, stops to relay in otic ganglia, located in the infratemporal fossa
  485. 485. Post ganglionic fibers runs to the parotid gland with the auriculotemporal nerve
  486. 486. Auriculotemporal
  487. 487. Lesser Petrosal</li></ul>Otic GangliaPre ganglionic Parasympathetic Secretomotor FibersPost ganglionic Parasympathetic Secretomotor Fibers<br />Damage to the gland can lead to damage to the facial nerveBlood Supply of the gland:<br /><ul><li>Arterial blood supply: through external carotid artery and terminal branches of superficial temporal artery and maxillary artery
  488. 488. Venous drainage: through maxillary vein and superficial temporal vein of the retromandibular</li></ul>Lymph nodes:<br /><ul><li>Drainage is by the parotid lymph nodes and the deep cervical lymph nodes</li></ul>Mumps: viral infection of the parotid gland<br />Parotitis: bacterial infection of the parotid gland<br />The Orbit<br />2 cavities, pyramidal in shape, located in the anterior view of the skull <br />Each orbit has:<br /><ul><li>Base: directed forwards
  489. 489. Apex: directed backwards
  490. 490. 4 orbital margins
  491. 491. 4 walls
  492. 492. Roof: separates the orbital cavity from the anterior cranial fossa. Formed from lesser wing of sphenoid and orbital plate of frontal bone
  493. 493. Floor: separates orbit from maxillary air sinuses. Formed from maxilla and zygoma
  494. 494. Lateral wall: separates orbit from temporal fossa, formed from zygomatic bone and greater wing of the sphenoid
  495. 495. -240665365760Medial wall: separates orbital and nasal cavities, formed from lacrimal, labyrinth of ethmoid bone and part of palatine bone
  496. 496. Openinings in the orbit:
  497. 497. Superior orbital fissure: communicates with the middle cranial fossa
  498. 498. Optic canal: communicates with the anterior cranial fossa/middle cranial fossa
  499. 499. Infra-orbital fissure: communicates with the pterygopalatine fossa
  500. 500. Supraorbital notch: communicates with the anterior surface of forehead
  501. 501. Infraorbital notch: communicates with the face
  502. 502. Nasolacrimal duct: connects the nasal cavity to the orbit
  503. 503. Contents of the orbit
  504. 504. Eyeball
  505. 505. Muscles
  506. 506. Nerves
  507. 507. Blood vessels
  508. 508. Fat
  509. 509. Lacrimal apparatus
  510. 510. Ciliary ganglion
  511. 511. Eyeball: spherical in shape, camera of the body, consists of 3 layers
  512. 512. Outer layer: a fibrous coat that protects the eye. Formed from sclera and cornea
  513. 513. Sclera:
  514. 514. provides attachment to the muscles
  515. 515. white in color
  516. 516. protects the eyeball
  517. 517. cornea:
  518. 518. transparent part
  519. 519. Middle layer: also called the vascular coat.
  520. 520. Choroid: becomes enlarged anteriorly to form the Ciliary body
  521. 521. iris: a forward extension of the Ciliary body which gives the color of the eye (pigmented coat)
  522. 522. pupil: an opening in the middle
  523. 523. 2 muscles of the eye for visual adaptation (affected by the amount of light)
  524. 524. Constrictor pupilae: is stimulated by high light intensity and is under parasympathetic control
  525. 525. Dilator pupilae: is stimulated by absence of light, under sympathetic control
  526. 526. Lens: connected to Ciliary body by suspensory ligaments
  527. 527. Ciliary muscles: group of involuntary muscles in Ciliary body
  528. 528. Change thickness of lens by changing length of suspensory ligaments
  529. 529. Allows for visual accommodation (ability to see far and near)
  530. 530. Inner layer: nervous coat called the retina
  531. 531. Has many photsensory receptors (rods and cons)
  532. 532. Rods: for dark light
  533. 533. Cons: for daylight, colors and moving objects
  534. 534. Optic nerve: originates from the retina from the rods and cons
  535. 535. Fibers travel posteriorly from the rods and cons to form the optic nerve
  536. 536. Fundus: site of attachment of the optic nerve to the eyeball. It has no rod and cons, thus it’s a blind spot
  537. 537. Chambers of the eyeball: divided because of presence of lens
  538. 538. Anterior chamber: contains aqueous humor (an aqueous watery fluid)
  539. 539. Posterior chamber: contains vitreous humor (jelly like fluid) it gives the round shape of the eyes
  540. 540. Eyelids:
  541. 541. Conjunctiva:
  542. 542. the lining of the eyelids
  543. 543. a transparent membrane inner surface which turns to line the eyeball
  544. 544. 422275257810inflammation can occur leading to red itchy eyes (conjunctivitis)
  545. 545. Fat:
  546. 546. Allows eye to move freely within the bony orbit
  547. 547. Supports the eyeball
  548. 548. Muscles
  549. 549. There are 2 groups of muscles in the eye
  550. 550. Intraocular: muscles inside the eyeball
  551. 551. Constrictor
  552. 552. Dilator
  553. 553. Ciliary muscles
  554. 554. Extraocular: muscles inside the orbit (outside the eyeball)
  555. 555. Recti (meaning straight)
  556. 556. Nerve Supply:LR6 SO4 3Superior rectus
  557. 557. Inferior rectus
  558. 558. Medial rectus
  559. 559. Lateral rectus
  560. 560. Oblique
  561. 561. Superior oblique
  562. 562. Inferior oblique
  563. 563. Levator palpebrae superioris</li></ul>Movements of the Eyes<br />Right eyeLeft eyeMovement Superior Rectus3Superior rectus3Inferior Rectus3Inferior Rectus3Lateral Rectus6Medial Rectus3Medial Rectus3Lateral Rectus6Inferior Oblique3Superior Rectus3Superior Rectus3Inferior Oblique3Superior Oblique4Inferior Rectus3Inferior Rectus3Superior Oblique4<br />-513715118745<br />Testing the function of the nerves through eye movements:<br /><ul><li>Abducens VI: look lateral by left eye
  564. 564. Trochlear IV: look down and lateral by right eye
  565. 565. Occulomotor III: look at any other direction
  566. 566. Problems With the eye:
  567. 567. Convergent Squint/diplopia/strabismus: double vision created when both eyes move medially
  568. 568. Divergent Squint; when one eye moves normally and the other eye moves laterally
  569. 569. Nerves:
  570. 570. Optic nerve II:
  571. 571. The remaining cranial nerves arise from the brain stempure sensory nerve for vision
  572. 572. arises from the retina and goes into the brain
  573. 573. Nasal part of retina views pictures coming from lateral/ temporal side
  574. 574. Lateral part of retina views vision from medial side, these are called visual field
  575. 575. Decussation: crossing of fibers to the opposite sideThe two fibers join to form the optic nerve
  576. 576. Nasal fibers of the optic nerves cross the midline forming the optic chiasma, it contains nasal fibers of both eyes
  577. 577. Optic tract: the continuation of the nasal fibers of the opposite side eye and the temporal fibers of the eye on the same side
  578. 578. If someone receives a hit in the back of the brain, it can affect vision (visual cortex)Optic chiasma is closely related to the pituitary gland, thus any damage to the pituitary gland affects the chiasmaThe optic tract ends in the visual cortex of the occipital lobe of the brain
  579. 579. 19050-77470Damage to the optic nerve: one eye is blind
  580. 580. Damage to chiasma: bitemporal hemianopia (blindness of the fields from the lateral side)
  581. 581. Damage to optic tract: contralateral hemianopia (blindness of the temporal of one eye and nasal of the other eye)</li></ul>Damage to the occulomotor causes: 3DDiplopia Drooping of upper eyelid= ptosisDilated pupilNerves passing through the optic cavity:<br /><ul><li>V1 of the trigeminal
  582. 582. Pure sensory nerve
  583. 583. Enters the orbit through superior orbital fissure
  584. 584. Branches:
  585. 585. Lacrimal: sensory, supplies lacrimal gland, conjunctive and the skin of the upper eyelid
  586. 586. Frontal: ends by giving 2 terminal branches
  587. 587. Supraorbital : supply upper eyelid, scalp, skin of the forehead, and frontal air sinuses
  588. 588. Supratrochlear : supply upper eyelid, scalp, skin of the forehead, and frontal air sinuses
  589. 589. Nasociliary:has 2 parts:
  590. 590. Visceral secretomotor: receives post ganglionic parasympathetic fibers from ciliay ganglia to supply the Ciliary body (muscles of the iris=constrictor pupilae) and lacrimal gland
  591. 591. Sensory: supplies nasal cavity, skin of the nose, skin of upper eyelid and ethmoidal air cells
  592. 592. Occulomotor nerve: arises from the brain stem and enters the orbit through the superior orbital fissure. Has 2 components:
  593. 593. Motor: to all muscles of the orbit except the superior oblique and the lateral rectus
  594. 594. Parasympathetic: preganglionic fibers which pass through the ciliary ganglia to supply the ciliary muscles (constrictor pupilae). It’s also responsible for visual accommodation
  595. 595. To test the function of the Trochlear:
  596. 596. Defect in eyeball movement
  597. 597. Drooping
  598. 598. Light reflex
  599. 599. Trochlear: arises from the brain stem.
  600. 600. Enters orbit through superior orbital fissure
  601. 601. Pure motor nerve
  602. 602. Supplies only superior oblique
  603. 603. Abducens arises from the brain stem.
  604. 604. Enters orbit through superior orbital fissure
  605. 605. Pure motor nerve
  606. 606. Supplies only lateral rectus
  607. 607. V2 of the trigeminal: pure sensory
  608. 608. Leaves skull through foramen Rotundum, to go to pterygopalatine fossa
  609. 609. The pterygopalatine ganglia is suspended by V2, but is functionally related to the facial nerveEnters the orbit and become Infraorbital nerve, which runs in the floor of the orbit and leaves the orbit through the Infraorbital foramen
  610. 610. Supplies
  611. 611. the skin of the face form angle of the eye to the angle of the mouth
  612. 612. nasal cavity
  613. 613. maxillary air sinus
  614. 614. upper teeth
  615. 615. part of the pharynx
  616. 616. Branches:
  617. 617. Posterior superior alveolar nerve.
  618. 618. Middle superior alveolar nerve
  619. 619. Anterior superior alveolar nerve
  620. 620. Ciliary Ganglia: small pin head sizes parasympathetic ganglia
  621. 621. Functionally related to occulomotor nerve
  622. 622. Receives preganglionic fibers
  623. 623. Postganglionic fibers pass through the nasociliary nerve
  624. 624. Blood Vessels
  625. 625. Arteries: ophthalmic artery,
  626. 626. a branch of internal carotid artery
  627. 627. enters the orbit through optic canal, and ends by giving terminal branches
  628. 628. supraorbital
  629. 629. Supratrochlear
  630. 630. Before entering the orbit it gives central retinal artery which runs in the center of the optic nerve
  631. 631. Damage can result in blindness, as it supplies the retina
  632. 632. Vein:
  633. 633. Superior ophthalmic vein: formed by union of supra orbital, Supratrochlear and angular veins
  634. 634. Inferior ophthalmic vein: forms by small veins in the orbit joined together and drain into the cavernous sinus
  635. 635. Both leave the obit
  636. 636. Lacrimal Apparatus: contains
  637. 637. Lacrimal gland
  638. 638. Canaliculi
  639. 639. Lacrimal sac
  640. 640. Nasolacrimal duct
  641. 641. Lacrimal gland:
  642. 642. an exocrine gland,
  643. 643. produces and secretes tears
  644. 644. located in upper lateral side of the orbit
  645. 645. has 2 parts
  646. 646. large orbital part
  647. 647. small palpebral part
  648. 648. receives its parasympathetic fibers from facial nerve, carried by greater petrosal nerve
  649. 649. tears flow on the anterior surface of the eyeball
  650. 650. blinking distributes the tears to moisten the eyeball
  651. 651. All tears will accumulate in the medial angle
  652. 652. Superior and inferior punctums: openings in the medial surface of the eye (corner) which pass the tears on to the canaliculi
  653. 653. Canaliculi: small ducts which drain the tears to the lacrimal sac, closely related to the medial wall of the orbit
  654. 654. Nasolacrimal duct: connects the lacrimal sac to the wall of the nasal cavity, thus making a pathway for draining the tears (passes through lacrimal bone)
  655. 655. Tears are then absorbed by the nasal mucosa
  656. 656. Nasal mucosa inflammation: blocked opening = teary eyes
  657. 657. Crying: excessive tear production, therefore inability of mucosa to absorb it all, leading to runny nose
  658. 658. 457835304800</li></ul>The end<br />