Anatomy of the Head - Musculoskeletal II Module, Part 1 - PDF

Musculoskeletal II module Part 1 (head)  Scalp *Def.& extent: Region covering skull vault. Extends from superciliary arches (eye brows) ant. to sup. nuchal lines post. & sup. temporal lines on each side. *La...

Musculoskeletal II module Part 1 (head)  Scalp *Def.& extent: Region covering skull vault. Extends from superciliary arches (eye brows) ant. to sup. nuchal lines post. & sup. temporal lines on each side. *Layers: 5 (from superficial to deep) -Skin (S); contains hair follicles & sebaceous glands. It is firmly adherent to underlying layer. -Connective (C) tissue; dense fibrous tissue binding skin to 3rd layer. It contains vessels & nerves of scalp & is rich in fat & fibrous septa. -Epicranial aponeurosis (A); wide tendon connecting frontal & occipital bellies of occipitofrontalis muscle. Attachment: Ant.; to frontal bellies. Post.; to occipital bellies, ext. occipital protuberance & highest nuchal lines. On each side; to sup. temporal lines. -Loose (L) areolar tissue (sub-aponeurotic); facilitates movement of aponeurosis. -Pericarnium (P); periosteum covering skull vault & is adherent to suture lines. *Applied anatomy: -Infection of connective tissue layer is limited due to presence of fibrous septa, but cut wound in this layer leads to severe bleeding due to its rich blood supply & inability of arteries wall to contract due to its attachment to fibrous septa. -Loose areolar tissue is scalp dangerous area because infection can pass into cranial cavity via emissary veins present in it. Hemorrhage from these emissary veins is large & separates scalp from skull bones. *Occipitofrontalis muscle: 2bellies connected by epicranial aponeurosis. Frontal belly Occipital belly Origin Epicranial aponeurosis Lat. 2/3 of highest nuchal line Insertion Skin of eye brow & root of nose Epicranial aponeurosis N. supply Temporal branch of facial n. Post. auricular branch of facial n. Action Raises eye brow Pulls post. part of scalp  *N. supply: 10 nerves on each half 5 infront of auricle 5 behind auricle 4 sensory 1 motor 4 sensory 1 motor (From trigeminal-5th cranial n.) (From facial n.) (From C2 & C3 spinal nerves) (From facial n.) *Supratrochlear & supraorbital; from frontal branch of *Temporal branch; To back of auricle, back of scalp, & upper part back of neck; *Post. auricular ophthalmic n., supply scalp ant. part & upper eyelid. leaves parotid & *Great auricular (C2 & C3); to small part of scalp branch; to -Supratrochlear: Passes through orbit superomed. angle, crosses zygomatic back near auricle lower part. occipital belly arch, supplying frontal *Lesser occipital (C2); to small part of scalp back occipito-frontalis. supplying forehead near median plane. -Supraorbital: Passes through supraorbital notch, supplying belly of occipito- near auricle upper part. scalp till lambdoid suture. frontalis & orbicularis *Greater occipital (C2); to upper part of scalp back. *Zygomaticotemporal; from zygomatic branch of maxillary n., oculi upper part. *Third occipital (C3); to lower part of scalp back & reaches scalp through zygomatico -temporal foramen supplying upper part of neck back. ant. part temple. *Auriculotemporal; from post. division of mandibular n., leaves parotid upper end & passes infront of auricle, supplying upper 2/3 of auricle lat. surface & post. part temple. *Blood supply: Arterial supply Venous drainage Ant. part Lat. part Post. part Ant. part Lat. part Post. part (2 arteries, from (1 artery, from E.C.A one of its 2 (2 arteries, from E.C.A) (2 veins) (1 vein) (2 veins) ophthalmic a. of I.C.A)) terminals) *Supratrochlear *Superficial temporal; leaves parotid *Post. auricular. *Supratrochlear *Superficial temporal; *Post. auricular; drains upper end & ascends infront auricle, enters parotid upper back auricle & scalp, *Supraorbital crosses zygomatic arch to end 5 cm *Occipital. *Supraorbital. end, uniting with unites with post. division above it by dividing into frontal & maxillary v. to form post. facial v. forming Supply scalp ant. part & parietal tortuous branches, supplying Pass upwards & backwards They unite at med. post. facial v. (retro- external jugular v. (E.J.V). anastomose with superficial scalp side & anastomose with deep to digastric post. belly, angle eye, forming mandibular v.). temporal a. branches. other arteries, forming collateral ant. facial v. supplying scalp back. *Occipital; drains scalp circulation between ICA & ECA. back into suboccipital -Branches: a)Parotid & TMJ. venous plexus in sub- b)Transverse facial a. c)Zygomatico- orbital a. d)Middle temporal a. occipital triangle. e)Ant. auricular a.: Auricle front & external auditory meatus. *Lymphatic drainage: *Ant. part; submandibular L.N. *Lat. part; parotid L.N. *Post. part; mastoid & occipital L.N.  Face *Muscles: Many & small, having bony origin from skull, inserting into skin of face, supplied by facial n. & are called muscles of facial expression. a)Circumorbital & palpebral: Orbicularis oculi b)Nasal: Procerus c)Buccolabial: Buccinator, levator labbii superioris, zygomaticus major & depressor anguli oris. D)Oral sphincter: Orbicularis oris. The most important of which are: Orbicularis oculi Orbicularis oris Buccinator (cheek muscle) Parts: Parts; Origin: Orbital part (around orbital margin); Intrinsic part; surrouds Upper fibers; alveolar process of arises from upper border of med. palpebral mouth, in upper & lower lips. maxilla, opposite upper 3 molars. ligament with bone above & below it. It Lower fibers; oblique line of mandible, curves around orbital margin to be inserted into lower border of med. palpebral ligament, opposite lower 3 molars. many fibers are inserted into eye brows skin. Middle fibers; pterygomandibular ligament Palpebral part; (in the eye lids); arises from (from pterygoid hamulus to mylohyoid line med. palpebral ligament & passes in upper & Extrinsic part; extension post. end). lower eye lids. Fibers of both lids end lat. from surrounding muscles in lat. palpebral raphe (ligament). as buccinator. Insertion: Upper fibers; upper lip Lower fibers; lower lip. Lacrimal part; arises from post. lacrimal Middle fibers; decussate at mouth angle, crest & from fascia covering lacrimal sac. It blends with palpebral part in eye lids. acting as a sphincter. N. supply: N. supply: N. supply: Temporal & zygomatic branches of facial n. Buccal & mandibular Buccal branch of facial n. branches of facial n. Action: Action: Action: -It closes eye firmly & suddenly in danger (orbital). Movement of lips & sphincter -Prevents food accumulation in vestibule. -It closes eye gently in sleep (palpebral). for mouth to close it. -Prevents saliva dribbling from mouth angle. -Blowing & whistling. -It stretches & dilates lacrimal sac to help in tears drainage (lacrimal). Relations: -Superficially; buccal fat pad, buccopharyngeal fascia, buccal n. & vessels, facial blood vessels. -Deeply; buccal mucosa. -Structures piercing; buccal n. & vessels, parotid duct. *Nerve supply: 1-Motor: Facial n. enters parotid & divides into 5 branches, which leav e parotid through its ant. border, except cervical branch. -Temporal branch: Supplies frontal belly of occipitofrontalis & orbicularis oculi upper part. -Zygomatic branches (upper & lower): Supplies lower part of orbicularis oculi & muscles between eye & mouth, including nose muscles. -Buccal branch: Supplies buccinator & upper part of orbicularis oris.  -Mandibular branch: Supplies lower part of orbicularis oris & lower lip muscles. -Cervical branch: Supplies platysma. Applied anatomy: Facial nerve (extracranial part) injury (Facial palsy); Paralysis of facial muscles leading to: -Patient cannot close his eye in affected side. -Dribbling of saliva from mouth angle in affected side. -Accumulation of food in mouth vestibule in affected side. -Deviation of mouth angle to opposite (healthy) side. 2-Sensory: 3 divisions of trigeminal (ophthalmic, maxillary & mandibul ar), except skin area on mandible angle & parotid (great auricular n. C2,3). Ophthalmic Maxillary Mandibular Branches; Branches: Branches; -Supraorbital; from frontal n. -Infraorbital; gives palpebral, -Buccal -Supratrochear; from frontal n. nasal & labial. -Mental; from inf. alveolar. -Zygomaticofacial; from -Palpebral; from lacrimal n. zygomatic n. -Infratrochear; from nasociliary n. -External nasal; from nasociliary n. Distribution: Distribution; Distribution: Skin of upper eyelid, forehead & Skin of face (lower eyelid, Skin of cheek, skin on lower lip, dorsum of nose. side of nose & upper lip) & mandible & chin. skin over zygomatic bone. Applied anatomy: Trigeminal neuralgia: Disease affecting sensory root of trigeminal nerve, caused by compression of the nerve by large blood vessel or by tumor. It is characterized by severe episodic pains restricted to areas supplied by maxillary and/or mandibular nerves. *Blood supply: A)Arterial supply; 1-Facial a.: Branch of E.C.A in neck, has 2 parts; cervical & facial. Facial part: -Enters face at anteroinferior angle of masseter, runs in a tortuous course to a point 1 cm behind angle of mouth, then it ascends vertically on side of nose, reaching eye med. angle & ending as angular a. which anastomoses with supraorbital & supratrochlear branches of ophthalmic a. -Branches; Inf. labial: To lower lip Sup. labial: To upper lip Nasal: To nose side, gives septal branch to nasal septum ant. part. 2-Transverse facial a.: Branch of superficial temporal a. inside parotid, leaves gland ant. border & passes on masseter below zygomatic arch & above parotid duct, supplying face. 3-Infraorbital a.: Termination of maxillary a., it comes out of infraorbital foramen & divides into; palpebral to lower eyelid, nasal to side nose & labial to upper lip. 4-Buccal a.: Branch of maxillary a., it supplies cheek. 5-Mental a.: Branch of inf. alveolar (from maxillary a.), supplies chin & lower lip.  Other face arteries: *Supratrochlear & supraorbital aa.: From ophthalmic a., supply upper eyelid & forehead *Dorsal nasal a.: From ophthalmic a. supplies nose dorsum. B)Venous drainage; 1-Ant. facial (facial) v. 2-Post. facial (retromandibular) v. Beginning At med. angle of eye by union of supraorbital & Inside parotid by union of superficial temporal & maxillary vv. supratrochlear veins. Course Runs a straight course downwards & backwards Descends superficial to ECA & deep to facial n. behind facial a., leaves face at anteroinferior angle of masseter, crosses mandible body & submandibular gland to enter neck. End In neck by uniting with ant. division of By dividing into ant. & post. divisions leaving gland post. facial v. forming common facial v. at its lower end. Ant division unites with ant. facial which ends in I.J.V. v. forming common facial & post. division unites with post. auricular v. forming external jugular v. Tributaries -Supraorbital & supratrochlear vv. -In face: Nasal, sup. & inf. labial, veins from buccinator, masseter & parotid, deep facial v. -In neck: Tonsillar & paratonsillar vv., submental & submandibular gland vv. Applied anatomy: Dangerous area of face: Triangular area in middle of face (including nose & upper lip), infection here reaches cavernous sinus (ant. facial v. to deep facial v. to pterygoid venous plexus to emissary v. through foramen ovale to cavernous sinus). * Lymph drainage: -Buccal; drain cheek -Parotid; drain upper & lat. part face. -Submandibular; drain nose, upper & lower lips. Parotid gland *Type & shape: Largest salivary gland, wedge shaped. *Site & extent: Lies in depression between mandible ramus & mastoid process. Extends forwards over masseter, backwards over part of sternomastoid, upwards to external auditory meatus & downwards to point 2 cm below & behind mandible angle. *Parotid fascia: Capsule of deep cervical fascia enclosing the gland. *Parts: -Main superficial part: Wedged between mandible ramus ant., mastoid process & sternomastoid post. -Deep part: Deep to mandible. -Small accessory part: Above parotid duct on masseter. *Relations: Surfaces Ends Borders  Lateral surface: Upper end: Anterior border: Skin, fascia, great auricular n. & superficial parotid L.N. Concave & related to external auditory meatus, Following structures leave it; the following structures appear at it; Anteromedial surface: Superficial temporal a. & v., auriculotemporal n. (extremely concave): Ramus of mandible, masseter -Parotid duct (with accessory part above it). & med. pterygoid. Lower end: -Transverse facial a. (above duct). Posteromedial surface; 2 cm below & behind angle mandible - 2 processes; Matoid & styloid. overlapping post. belly digastric, the following structures leave it; -2 muscles attached to mastoid process; Sternomastoid Cervical branch of facial n., ant. & post. -Temporal & zygomatic branches of facial n. (superficially) & post. belly digastric (deeply). divisions of post. facial (retromandibular) v. (above duct). -3 muscles & 2 ligaments attached to styloid process. -2 blood vessels; I.C.A & I.J.V with last 4 cranial nerves in between. -Buccal & mandibular branches of facial n. N.B. 2 structures enter this surface; facial n. & E.C.A. (below duct). *Surface anatomy: -Upper end: Line concave upwards, around external auditory meatus, from auricle tragus (mandible head) to middle of mastoid process. -Ant. border: Line from tragus downwards & forwards to middle of masseter then downwards & backwards to point 2 cm below & behind mandible angle. -Post. border: Line from mastoid process to point 2 cm below & behind mandible angle, running along ant. sternomastoid border. *Parotid duct: -Thick walled with narrow lumen, 5 cm long. Appears at gland ant. border, passing horizontally on masseter below zygomatic arch. At masseter ant. border, it pierces ;buccal pad of fat, buccopharyngeal fascia, buccinator & buccal mucosa to open in vestibule opposite upper 2nd molar. -Surface anatomy: Middle 1\3 of line from tragus to point midway between nose ala & red margin of upper lip. *Structures within gland: Facial n. Enters posteromed. surface close to stylomastoid foramen , running as most superficial structure & ending by dividing into 5 terminals (temporal, zygomatic, buccal, mandibular & cervical). Post. facial v. Formed inside gland behind mandible neck by union of maxillary & superficial temporal veins. It descends between facial n. & E.C.A, leaving gland through its lower end as ant. & post. divisions. E.C.A Passes deep to gland lower end entering gland through its posteromedial surface, running as deepest structure & ending opposite mandible neck by dividing into 2 terminals (maxillary & superficial temporal). Deep parotid L.N. In gland substance, around blood vessels. Auriculotemporal n. Runs a short course *Nevre & blood supply, lymphatic drainage : N. supply Blood supply Lymph drainage -Sensory: Auriculotemporal n. -Sympathetic: Plexus around E.C.A & M.M.A. -Arterial: Superficial & deep parotid nodes -Parasympathetic: Glossopharyngeal n.; preganglionic fibers arise Superficial temporal a. which drain in deep from inf. salivary nucleus of medulla, pass with tympanic branch of glosso- -Venous: cervical nodes. pharyngeal n., entering middle ear & forming tympanic plexus. It gives Post. facial (retro-mandibular) lesser superficial petrosal n. which leaves skull via foramen ovale & relay in & external jugular vv. otic ganglion. Post- ganglionic fibers join auriculotemporal n. to reach gland.  *Applied anatomy -Inflammation of gland (parotitis): Infection reaches gland from mouth through duct or via blood stream. Patient complains of parotid swelling with raised or everted auricle lobule & severe pain (due to stretch of tight parotid capsule) which increases during mastication (due to close relation of gland to T.M.J). -Parotid tumors: Affects gland superficial to facial n. branches, if benign it will not affect the n. but if malignant it compresses & invade the n. leading to facial n. paralysis. Temporal & infratemporal fossae -Temporal Fossa (Temple): Region on head side lying below temporal lines & above zygomatic arch. Contents: Temporalis muscle, deep temporal vessels & nerves. -Infratemporal Fossa: Region below & med. to zygomatic arch, behind maxilla & deep to mandible ramus. Contents: 1-Muscles of mastication: Temporalis Insertion, med. & lat. pterygoids. 2-Blood vessels: A)1ST & 2ND parts maxillary a. & corresponding branches B)Pterygoid venous plexus. 3-Nerves: Mandibular n. & its branches, otic ganglion & chorda tympani. 4-Ligaments: Sphenomandibular ligament. Muscles of mastication Muscle Origin Insertion N. supply Action Temporalis -Temporal fossa. -Tip & med. surface 2 deep temporal -Elevation mandible -Inf. temporal line. of coronoid process. nn. (ant. division (ant. fibers). (fan shaped) -Ant. fibers: Vertical. -Temporal fascia. -Ant. border mandibular n). -Retraction mandible mandible ramus. (post. fibers). -Middle fibers: Oblique. -Post. fibers: Horizontal. Masseter -Superficial fibers: Lat. surface of Masseteric n. -Protraction mandible Lower border mandible ramus. (ant. division (superficial fibers). -Superficial fibers: Oblique. zygomatic arch. mandibular n). -Elevation mandible -Deep fibers: Vertical. -Deep fibers: (deep fibers). Deep surface zygomatic arch. Lat. pterygoid -Upper head: -Pterygoid fovea N. to lat. -Depression mandible (lat. Infratemporal surface of mandible neck. pterygoid pterygoids both sides). & crest of greater wing -Capsule & articular (ant. division -Protraction mandible to sphenoid. disc of T.M.J. mandibular n). opposite side (lat. & med. -Lower head: pterygoids one side). Lat. surface of - Side to side movement lat. pterygoid plate. (lat. & med. pterygoids of both sides alternatively). Med. pterygoid -Superficial head: Med. surface of N. to med. -Elevation mandible (med. Maxillary tuberosity. angle & ramus of pterygoid pterygoids both sides). Deep head: mandible, below (main trunk -Protraction mandible to Med. surface of mandibular foramen. mandibular n). opposite side (lat. & med. lat. pterygoid plate pterygoids one side). - Side to side movement (lat. & med. pterygoids of both sides alternatively). Relations of Lat. pterygoid: 1-Between its two heads: Maxillary a. enters & buccal n. comes out. 2-Above (at upper border): Two deep temporal nerves & vessels, nerve to masseter.  3-Below (at lower border): 1st part maxillary a., lingual n., inferior alveolar n. & vessels. 4-Superficial relations: 2nd part of maxillary a., pterygoid venous plexus, buccal nerve (on lower head) & three muscles; temporalis, masseter & superficial head of med. pterygoid. 5-Deep relations: *Two muscles: Deep head of med. pterygoid & tensor palati. *Two nerves: Mandibular n. with otic ganglion & chorda tympani. *Two arteries: Middle & accessory meningeal arteries. Temporomandibular joint *Articular surfaces: Head of mandible (below), mandibular fossa & articular tubercle (above).They are covered by white fibrocartilage. *Type: Synovial, condylar, biaxial joint. *Capsule: Above; mandibular fossa margins & articular tubercle, Below; around mandible neck. Capsule is thickened lat. forming temporomandibular ligament & is attached to articular disc margins. *Articular disc: Oval plate of dense avascular fibrous tissue, it divides cavity into upper & lower compartments. Its upper surface is concavoconvex, while its lower surface is concave. Its periphery is attached to capsule & it receives lat. pterygoid insertion. *Ligaments: Temporomandibular Stylomandibular Sphenomandibular Thickened triangular lat. part of capsule. Attached Extends from styloid process ant. surface Extends from spine of sphenoid to zygomatic arch tubercle (above), lat. & to post. border of angle & ramus mandible. It to lingula of mandible. post. surfaces of mandible neck (below).Only separates parotid from submandibular gland. proper ligament supporting the joint. *Movements: Depression Elevation Protraction Retraction Side to side (opening mouth) (closing mouth- (forward movement) (backward movement occlusal position) movement) Movement: Movement: Movement: Movement: Movement: Simple hinge rotation of head down- Reversed movement Lower teeth are drawn Mandible is drawn Chewing & grinding. wards around horizontal axis followed to depression. forwards over upper teeth. back-wards to by gliding movement of head & position of rest. articular disc forwards & downwards to lie below articular tubercle. Muscles producing: Muscles producing: Muscles producing: Muscles producing: Muscles producing: Lat. pterygoids, helped by gravity. Temporalis, Med. & lat. pterygoids. Temporalis Med. & lat. Digastric, mylohyoid & geniohyoid masseter & Masseter superficial (post. fibers). pterygoids of help lat. pterygoids in resistance. med. pterygoids. fibers has small effect. both sides (alternatively). *N. supply: Auriculotemporal & masseteric nerves (from mandibular n.). *Blood supply: Superficial temporal & maxillary arteries (from E.C.A). *Applied anatomy: With mouth opened, condyles are below articular tubercles. Sudden violence, even muscular spasm (convulsive yawn) may displace one or both condyles into infratemporal fossa (ant. dislocation). Reduction by depressing mandible post. with elevating chin at same time.  Trigeminal (5 cranial) N.th Arises from pons by 2 roots; *Sensory root (largest): Has trigeminal ganglion (lying in special depression in petrous bone ant. surface near its apex), dividing into 3 sensory branches (ophthalmic, maxillary & mandibular), supplying skin of scalp, face & ant. 2\3 tongue. *Motor root (smallest): Joins mandibular n. & supplies 8 muscles; 4 of mastication, tensor palati & tensor tympani, mylohyoid & ant. belly digastric. a)Mandibular nerve *Origin: -Sensory root (large): From trigeminal ganglion. -Motor root (small): Motor root of trigeminal n., from pons. *Course & end: They leave skull through foramen ovale, where they unite just below it forming main trunk, which descends 1 cm in infratemporal fossa infront of mandible neck, to end by dividing into ant. (small & mainly motor) & post. (large & mainly sensory) divisions. *Branches: A) From trunk B)From ant. division -Motor: N. to med. pterygoid; supplies med. -Motor: 1-Two deep temporal nerves; for temporalis muscle. pterygoid, tensor palati & tympani muscles. 2-N. to masseter muscle; passing through mandibular notch. 3-N. to lat. pterygoid muscle. -Sensory: Nervus spinosus; enters middle cranial -Sensory: Buccal n.; continuation of ant. division, supplying fossa through foramen spinosum to supply dura. skin covering & mucosa lining buccinator muscle. C)From post. division Auriculotemporal n. Inf. alveolar n. Lingual n. -Deep to mandible ramus; it is joined Arises by 2 roots around middle (largest branch of post. division). It by chorda tympani deep to lat. pterygoid, then it meningeal a., passes backwards deep descends on med. pterygoid behind descends on med. pterygoid infront of inf. alveolar n. to mandible neck ascend within parotid lingual n., it enters mandibular foramen -Deep to mandible body; it passes forwards in a behind T.M.J., leaves parotid through & runs in mandibular canal, it ends at faint groove below last molar, covered by mucosa. its upper end crossing zygomatic arch mental foramen by dividing into -At tongue side; it crosses styloglossus , then to reach scalp where it divides into branches. mental & incisive terminal branches. hyoglossus where it suspends submandibular ganglion by 2 roots. It hooks around submandibular duct & passes forwards deep to sublingual gland to reach tongue. Branches: Branches: Branches: -Parotid: Sympathetic & para- -N. to mylohyoid: Runs in mylohyoid -General sensory: To ant. 2\3 tongue, gum, floor of sympathetic fibers (from otic groove supplying mylohyoid & ant. mouth, submandibular & sublingual glands. belly of digastric muscles. ganglion),sensory fibers. -Taste sensory: To ant. 2\3 tongue. -Dental branches: Arise in mandibular -Articular: To T.M.J. -Parasymp.: To submandibular & sublingual glands canal supplying lower molars & pre- -Sensory: To skin of upper 2\3 lat. molars (inf. alveolar itself), lower (after relaying in submandibular ganglion). incisors & canine (incisive branch).They N.B.: Taste & parasymp. are from chorda tympani. surface auricle, post. 1\2 temple, external auditory meatus & ear drum. also supply gum & alveolar bone. Mental n.: Comes out of mental foramen, to skin of chin & lower lip. Otic ganglion *Type &site: Parasympathetic ganglion, lies in infratemporal fossa just below foramen ovale, suspended from mandibular n. trunk (deep surface) by n. to med. pterygoid. *Roots & branches:  Roots Branches Motor root: 2 fibers from n. to med. pterygoid; traversing ganglion without relay. Tensor palati & tensor tympani. Sympathetic root: Sympathetic plexus around middle meningeal a.; Joins auriculotemporal n. to reach parotid traversing ganglion without relay. gland, supplying its blood vessels. Parasympathetic root (lesser superficial petrosal n.): From tympanic Post ganglionic fibers join auriculo- plexus (tympanic branch of glossopharyngeal n.) in middle ear, it leaves skull temporal n. to reach & supply parotid. through foramen ovale; relaying in ganglion. b)Maxillary n. *Origin: Purely sensory n. from trigeminal ganglion, intermediate in position & size betwe en ophthamic & mandibular nn. *Course & end: Passes forwards in lat. wall of cavernous sinus, then it leaves middle fossa through foramen rotundum to reach pterygopalatine fossa. Passes through inf. orbital fissure (now called infraorbital n.), infra-orbital groove, infraorbital canal to reach face through infraorbital foramen, where it ends by dividing into palpebral, nasal & labial branches. So course can be divided into: A;In cranial cavity B;In pterygo-palatine fossa C;In orbit floor D;In face (in C & D, called infraorbital n.). *Branches: A)In cranial cavity Meningeal nerve: Supplies dura of middle cranial fossa. B)In pterygopalatine fossa -Two ganglionic nerves: Suspend sphenopalatine ganglion to maxillary n. -Zygomatic n.: Enters orbit through inf. orbital fissure & divides into ; *Zygomaticotemporal n.: Supplies skin of ant. part of temple. *Zygomaticofacial n.: Supplies skin on body of zygomatic bone. -Post. sup. alveolar n.: Leaves fossa via pterygomaxillary fissure, then pierces back of maxilla & descends in it , supplying upper molars, gum & maxillary sinus. C)In orbit -Middle sup. alveolar n.: Arises from inraorbital n. in infraorbital groove, it descends in lat. wall of maxillary sinus, supplying it with upper premolars & gum. -Ant. sup. alveolar n.: Arises from inraorbital n. in infraorbital canal, it descends in ant. wall of maxillary sinus, supplying it with upper incisors, canine & gum. D)In face -Palpebral n.: To skin of lower eye lid -Nasal n.: To skin of nose side -Labial: To skin of upper lip. Sphenopalatine ganglion *Type & site: Parasympathetic, in pterygopalatine fossa suspended from maxillary n. by 2 roots. *Roots & branches: Roots Branches sensory root: 2 ganglionic fibers from *Orbital: Pass through inf. orbital fissure to supply orbital periostium. maxillary n.; traversing ganglion without relay. *Pharyngeal : Supply nasopharynx & auditory (Eustachian) tube. *Palatine: -Greater palatine n.; passes through palatine greater canal & foramen, reaching & supplying hard palate (post. part). Also supplies posteroinf. part lat. wall nose. -Lesser palatine nerves ; pass through greater palatine canal & lesser palatine foramina, reaching & supplying soft palate & palatine tonsils. *Nasal: Reach nasal cavity via sphenopalatine foramen, divides into 2 groups; -Lat. nasal (short sphenopalatine): To posterosup. part lat. wall nose. -Med. nasal (long sphenopalatine): To nasal septum (post. part) & one of them (naso- palatine n.) passes through incisive canal to reach & supply ant. part of hard palate. Sympathetic root (deep petrosal It supplies blood vessels of orbit, pharynx, palate &nose. n.): Sympathetic plexus around ICA; traversing ganglion without relay. Parasympathetic root (greater It supplies lacrimal gland & mucus glands of pharynx, palate &nose. superficial petrosal n.): From facial n.in petrous bone, it relays in ganglion. N.B.: Deep petrosal & greater superficial petrosal nerves form n. of pterygoid canal (vidian n.) which pass through pterygoid canal reaching ganglion.  Maxillary artery *Beginning: Inside parotid, opposite mandible neck, as larger of the 2 terminal branches of external carotid artery. *Course & end: -It passes forwards, med. & upwards, reaching pterygopalatine fossa, where it ends by dividing into many branches. -Parts: 1st: Lies deep to mandible neck within parotid, passing horizontally from its origin till lat. pterygoid lower border. 2nd: Passes obliquely superficial to lat. pterygoid lower head (sometimes deep to it). 3rd: Passes between lat. pterygoid 2 heads, then through pterygomaxillary fissure reaching pterygopalatine fossa. *Branches of 1st part: Middle meningeal a. See below Accessory meningeal a. Passes deep to lat. pterygoid infront of M.M.A., entering middle cranial fossa via foramen ovale, supplying dura mater & trigeminal ganglion. Inferior alveolar a. Passes through mandibular foramen inside mandibular canal, ending opposite mental foramen by dividing into incisive & mental branches. It supplies mandible, lower teeth, lower lip & gives mylohyoid a. (descending in mylohyoid groove). Ant. tympanic a. Supplies tympanic cavity & tympanic membrane (ear drum). Deep auricular a. Supplies external auditory meatus & tympanic membrane. *Branches of 2nd part: -Muscular arteries: For muscles of mastication -Buccal artery: To face. *Branches of 3rd part: Infraorbital a. Passes through inf. orbital fissure, infraorbital groove, infraorbital canal to reach face through infraorbital foramen, where it divides into palpebral, nasal & labial branches. It gives ant. sup. alveolar artery (in infraorbital canal) supplying upper incisors & canine teeth. Pharyngeal & A. of pterygoid canal. Supplies nasopharynx. Greater palatine a. Passes through greater palatine canal & foramen to reach hard palate supplying it, then it passes through incisive canal to reach nasal septum supplying it. It gives 2 lesser palatine arteries supplying soft palate & palatine tonsil. Sphenopalatine artery Passes through sphenopalatine foramen to reach nasal cavity supplying it. Post. sup. alveolar a. Supplies upper molars, premolars & maxillary sinus. Middle meningeal artery *Beginning, course & end: Branch from 1 part maxillary artery. Ascends deep to lat. pterygoid, between auriculotemporal n. 2 roots. It enters middle cranial fossa via st foramen spinosum, where it passes forwards & laterally shortly (2 cm) in a groove on its floor, ending by dividing into ant. & post. terminal branches. *Surface anatomy: Draw a line 2 cm long upwards & forwards from a point at middle of zygomatic arch, then divide it into 2 lines; Ant. branch: Line upwards & forwards towards pterion, then upwards & backwards towards point midway between nasion & inion. Upper part of the artery is 1 finger breath behind coronal suture & 1 finger breath infront of brain central sulcus. Post. branch: Line backwards & upwards towards lambda. *Branches: 1- meningeal : to Dura mater 2-Skull bones & periostium 3-Trigeminal ganglion & Its roots. 4-Tympanic: To tympanic cavity 5-Orbital: To orbit (via sup. orbital fissure). *Applied anatomy: May be torn in temporal fractures or by injury separating dura from bone leading to extradural hemorrhage. Trephining is necessary reducing cerebral compression. Pterygoid venous plexus *Site: Plexus of veins superficial & deep to lat. pterygoid. *Beginning: It receives tributaries corresponding to branches of maxillary a. *End: Post. by forming maxillary v., which enters parotid & joins superficial temporal v. forming retromandibular v. *Communications: -Ant.: With ant. facial v. via deep facial v. -Above: With cavernous sinus via emissary veins (foramen ovale & lacerum)). -Ant. & above: With inf. ophthalmic v. via vein (inf. orbital fissure). Cranial cavity Contents: 1-Brain & cranial nerves 2-Dura mater & its folds 3-Dural venous sinuses & emissary veins. 4-Pitutary gland 5-Petrosal nerves 6-Internal carotid & middle meningeal blood vessels. A)Dural folds: Duplication (2 layers) of inner layer dura, acting as septa, separating different parts of brain & stabilizing them. Falx cerebri Falx cerebelli Tentorium cerebelli Diaphragma sellae *Shape & site: Sickle shaped fold, *Shape & site: Sickle shaped * Shape & site: Tent shaped fold, separating cerebellum from occipital lobe cerebrum. *Site: Covering between 2 cerebral hemispheres. fold, between 2 cerebellar hemispheres. sella turcica & pituitary gland. *Attachment & sinuses related: * Attachment & sinuses related: * Attachment & sinuses related: *Attachment: -Apex; attached to crista galli & frontal crest. -Extends from internal occipital -Free border; U-shaped, forming tentorial notch which surrounds midbrain Attached to -Base; attached to tentorium cerebelli protuberance (above) to foramen & is attached to ant. clinoid process. the 4 clinoid & contains straight sinus. magnum (below), being attached -Attached border; attached on both sides to post. clinoid processes, sup. processes. -Upper border; Convex, attached to to internal occipital crest. petrosal sulci & transverse sulci. sup. sagittal groove & contains sup. -Contains occipital sinus. N.B.: Free & attached borders cross each other at petrous bone apex (attached lies sagittal sinus. deep to free). 3 cranial nerves pierce dura at this point of decussation: -Lower border; Concave & free, contains Oculomotor (3rd cranial n.) infront of the point, trochlear (4th cranial n.) at inf. sagittal sinus in its post. 2/3. the point & trigeminal (5th cranial n.) behind the point. -Contains;-Straight sinus, in middle at its attachment with falx cerebri. -Sup. petrosal sinus (infront) & transverse sinus (behind) in attached border (on both sides). Blood vessels & n. supply of meninges: Site of dura Blood supply Nerve supply Ant. cranial fossa Ant. & post. ethmoidal blood vessels Ant. ethmoidal n. Middle cranial fossa 1-Middle meningeal a. from maxillary a. 1-Meningeal branch of maxillary n. 2-Accessory meningeal a. from maxillary a. 2-Nervus spinosus from mandibular nerve trunk. Post. cranial fossa Meningeal branches of: 1-Meningeal branch of vagus n. 1-Occipital a. 2-Vertebral a. 3-Ascending pharyngeal a. 2-Meningeal branch of hypoglossal n.  B)Dural venous sinuses: -Spaces between outer & inner layers dura, lined with endothelium & have no valves. -Receive venous blood from skull, brain, pituitary gland, orbit & inner ear. Receive C.S.F (via arachnoid villi) & many emissary vv. Single sinuses Sup. sagittal (S.S.S) Inf.sagittal Straight Occipital Basilar plexus of veins *Begins at foramen caecum, passes * passes back-wards in post. 2/3 of *Formed by union of inf. sagittal sinus *Begins from confluence of sinuses or one *Lies on clivus, backwards in upper attached border lower free border falx cerebri. & great cerebral v. Passes backwards transverse sinus & descends in falx cerebelli connecting both falx cerebri. Ends at internal occipital in midline at attachment of falx inf. pertosal sinuses. protuberance, usually shifts to Rt., forming cerebri with tentorium cerebelli. Rt. transverse sinus. *Tributaries; sup. cerebral v., *Tributaries; veins from brain med. side. *Ends at internal occipital *Divides into 2 branches near foramen magnum, 2 emissary vv., arachnoid villi & protuberance, usually shifts to ending in sigmoid sinuses. It communicates meningeal vv. Lt., forming Lt. transverse sinus. with internal vertebral venous plexus. Paired sinuses Transverse Sigmoid Sup. petrosal Inf. petrosal Sphenoparietal Cavernous *Rt. is usually continuation of S.S.S, while Lt. is *S shaped, *Arises from post. end *Arises from post. end cavernous sinus, *Passes med. along See usually continuation of straight sinus. Passes lat. continuation of cavernous sinus, passes descends in inf. petrosal sulcus (petro- post. border of lesser below in attached border tentorium cerebelli, reaching mastoid transverse sinus. backwards in attached occipital fissure). wing sphenoid. base process to become sigmoid sinus. border tentorium. *Tributaries; sup. petrosal *Passes through *Ends in transverse sinus. *Leaves skull via jugular foramen, ending *Ends in cavernous sinus. sinus, cerebellar & skull veins. jugular foramen, in I.J.V outside skull.Both sinuses are becomes I.J.V. connected by basilar plexus of veins. Cavernous sinus *Def., size & site: Short wide sinus consisting of many intercommunicating channels, 2x2 cm, lying on each side of body of sphenoid. *Relations: Ant.: Apex of orbit & sup. orbital fissure Post.: Apex of petrous bone & trigeminal ganglion. Med.: Body sphenoid, sphenoid sinus, pitutary gland Lat.: Uncus of temporal lobe Above: I.C.A. *Contents: Inside sinus: I.C.A & abducent (6th cranial) n. inferolat. to the a. Embedded in lat. wall: Oculomotor (3rd cranial) n., trochlear (4th cranial) n., ophthalmic & maxillary nerves (2 divisions of trigeminal -5th cranial- n.).  *Communications (tributaries): Anteriorly Posteriorly Above Below Medially Others Ophthalmic veins: Connect Sup. petrosal sinus: Connects it Superficial middle cerebral v. Emissary v. through foramen ovale : Connects it 2 intercavernous Pitutary it with ant. facial v. with transverse sinus. with pterygoid venous plexus. sinuses: Connect both gland vv. Emissary veins through foramen lacerum: Connect cavernous sinuses. Spheno-parietal sinus. Inf. petrosal sinus: Connects it it with pterygoid & pharyngeal venous plexuses. with I.J.V. Central Emissary vein through carotid canal: Connects it retinal v. with pharyngeal venous plexus or with I.J.V. *Applied anatomy: Cavernous sinus thrombosis: Caused by transmission of infection from dangerous area of face to cavernous sinus. It is characterized by fever & internal squint (abducent n. paralysis), the eye becomes congested (black) & oedematous (venous drainage obstruction) & later on eye bulges to outside (proptosis). C)Emissary veins *Def.: Valveless veins connecting dural sinuses (inside skull) with veins in scalp & face (outside skull), passing through emissary foramina in skull. *Function: Equalize venous pressure, between dural sinuses & veins outside skull. *Clinical importance: They can transmit infection from outside skull to dural sinuses inside skull, causing septic thrombosis of sinuses as cavernous sinus thrombosis. *Sites & distribution: 2 veins connected to S.S.S 3 veins connected to cavernous sinus 3 veins connected to sigmoid sinus *V. through foramen caecum: Connects it with veins of nose. *V. through foramen ovale: Connects it with pterygoid venous plexus. *V. through mastoid foramen: Connects it with occipital vv. *V. through parietal emissary foramen: Connects it *veins through foramen lacerum: Connect it with pterygoid & *V.through post. condylar foramen: Connects it with with scalp occipital veins. pharyngeal venous plexuses. suboccipital venous plexus. *V. through carotid canal: Connects it with pharyngeal venous *V. through hpoglossal canal: Connects it with I.J.V. plexus or with I.J.V.  Orbit *Bony orbit: Pyramidal shaped, narrow from behind forming apex (optic canal) & wide from in front forming orbital opening in face. It has 4 walls; Roof Floor Med. wall Lat. wall 1-Orbital plate of frontal bone 1-Orbital surface of maxilla 1-Frontal process of maxilla. 1-Greater wing of (main part). (main part). 2-Lacrimal bone. sphenoid (post.). 2-Lesser wing of sphenoid (most 2-Orbital surface of zygomatic 3-Orbital surface of ethmoid bone. 2-Frontal process of post. part). bone (anterolat. part). 4-Body of sphenoid zygomatic bone (ant.). N.B.: Contains lacrimal fossa in its N.B.: Contains infra-orbital (from before backwards). anterolat. part for lacrimal gland. groove & canal. *Orbital fissures: Sup. orbital fissure Inf. orbital fissure It lies between lesser wing of sphenoid (in roof) & greater It lies between maxilla (in floor) & greater wing of wing of sphenoid (in lat. wall).It communicates orbit with sphenoid (in the lat. wall).It communicates orbit with middle cranial fossa. infratemporal & pterygopalatine fossae. *Contents of orbit: *Eyeball *Extraocular muscles. *Nerves: a-Optic n.: For vision b-Ophthalmic n.: For general sensations. c-Oculomotor, trochlear & abducent nn.: Motor to eyeball muscles. d-Sympathetic fibers: From sup. cervical ganglion. e-Parasympathetic (ciliary) ganglion: Attached to nasociliary n. *Vessels: Ophthalmic a. & vv. *Lacrimal apparatus *Pad of fat. a)Eye lids Thin movable folds covering front of eyes & protecting them from injury by rapid closure. The upper eye lid is larger and more mobile than lower lid. The two eye lids are united together at med. & lat. ends, elliptical space which appears between their margins is called palpebral fissure. Margins of lids contain short thick curved hairs called eye lashes. Structure (from superficial to deep): 1-Skin: very thin. 2-Superficial fascia: very lax, delicate & devoid of fat. 3-Palpebral part of orbicularis oculi: Thin & parallel to palpebral fissure. 4-Loose connective tissue layer: Deep to orbicularis oculi, contains main nerves & vessels of eye lid, local anesthesia should be injected here. 5-Tarsus: Thin elongated plate of dense fibrous tissue giving form & support. Their med. & lat. ends are connected by med. & lat. palpebral ligaments. 6-Tarsal glands: Yellowish glands arranged in a single row about 30 in upper lid and few in lower lid, embedded in deep groove on tarsus post. surface. Their oily secretion prevent lacrimal fluid overflow on cheek. 7-Conjunctiva: Transparent mucous membrane lining upper & lower eyelids. It is reflected over front of sclera, line of reflection above is called sup. fornix while below is called inf. fornix. The sup. fornix receives lacrimal gland ducts. Over sclera, conjunctiva is loosely connected to eye ball & on reaching cornea it continues as corneal epithelium. b)Lacrimal apparatus a.Lacrimal gland: Formed of 2 parts; large orbital part lying in lacrimal fossa (at anterolat. part of orbital roof) above levator palpebrae superioris muscle & a small palpebral part lying below the muscle. It has 10-12 short ducts open in lat. part of sup. conjunctival fornix. It is innervated by greater superficial petrosal n. (facial n.) which relays in spheno-palatine ganglion, postganglionic fibers join maxillary nerve, pass in its zygomatic n., then into zygomaticotemporal n., then through a communicating ramus to lacrimal n. which supplies the gland. b.Lacrimal canaliculi: Two canaliculi one for each eyelid. Runs in corresponding eyelid edge, extending from lacrimal punctum at top of lacrimal papilla & draining tears into the lacrimal sac. c.Lacrimal sac: Lies in lacrimal groove (in ant. part of orbit medial wall). Upper blind end of sac is called fundus while its lower end is continuous with nasolacrimal duct. d.Nasolacrimal duct: Starts from lacrimal sac & passes downwards inside nasolacrimal canal to open at ant. part of inferior nasal meatus.  c)Extraocular muscles Levator palpebrae superioris 4 Recti Sup. oblique Inf. oblique Origin Orbital roof infront of optic Common tendinous ring surrounding optic foramen & med. part of Orbital roof above & Floor of orbit just foramen. sup. orbital fissure. Each arises from ring corresponding side, lat. med. to optic foramen. lat. to naso- rectus has another head from sup. orbital fissure margin. It lies just above & med. lacrimal groove. to sup. rectus origin. Insertion Under orbital roof into tarsus Each passes forwards to be inserted into sclera short distance about (5½- Tendon passes forwards Muscle passes & skin of upper eyelid, sup. 7½ mm) behind corneoscleral junction (MR 5½, IR 6½, LR 7 & SR 7½ mm). through trochlea, then backwards, up- conjunctival fornix. curves backwards, wards & lat. below downwards & lat. to eyeball, to insert insert into sclera behind into sclera behind eyeball equator. eyeball equator. N. supply All are supplied by oculomotor (3rd cranial n.) except, sup. oblique by trochlear (4th) & lat. rectus by abducent (6th) cranial nn. Action Elevates upper eyelid. Muscle deep *Lat. rectus: Moves eye ball lat. (abduction). Moves eye ball downwards Moves eye ball part is smooth (Muller's muscle) & *Med. rectus: Moves eye ball med. (adduction). (depresses), lat. (abducts) upwards (elevates), supplied by sympathetic fibers. N.B.: Movements of abduction and adduction occur around an with intorsion. lat. (abducts) imaginary vertical axis. with extorsion. *Sup. rectus: Moves eye ball upwards (elevates) & med. (adducts) with slight intorsion. *Inf. rectus: Moves eye ball downwards (depresses) & med. (adducts) with slight extorsion. N.B.: Movements of intorsion & extorsion occur around an imaginary anteropost. diameter, while movements of upwards & downwards rotation occur around an imaginary transverse axis.  d)Nerves of orbit 1)Sensory nn. 1-Ophthalmic division of trigeminal n.: It divides into 3 branches before entering orbit through sup. orbital fissure; a.Nasociliary nerve: Carries ciliary ganglion. It enters orbit through med. part of S.O.F., passing med. & crossing optic n. to reach orbital med. wall, where it passes forwards giving the following branches: *Two long ciliary nerves; run along optic n. to pierce eyeball back carrying sympathetic fibers to dilator pupillae muscle. *Ant. ethmoidal n.; passes via ant. ethmoidal foramen entering ant. cranial fossa, then passes to nasal cavity supplying it & leaves it as external nasal n. *Post. ethmoidal n.; passes through post. ethmoidal foramen to supply ethmoidal air cells. *Infratrochlear n.; passes below trochea to eye med. angle, supplying med. parts of eyelids & nose root. b.Frontal nerve: Largest branch, enters orbit through middle of S.O.F. Passes forwards below orbital roof & above levator palpebrae muscle, where it divides into two terminal branches; supraorbital & supratrochlear nerves which supply skin of upper eye lid & scalp ant. part. c.Lacrimal nerve: Smallest branch, enters orbit through lat. end of S.O.F. to end in lacrimal gland. It gives palpebral branch supplying upper lid lat. 1/3. It receives a twig from zygomaticotemporal branch of maxillary n. containing secretomotor fibers to lacrimal gland. 2-Optic (2nd cranial) n.: It is axons of retinal ganglionic cells. It is surrounded by extension of meninges so it differs from other cranial nerves. This means that optic n. is surrounded by subarachnoid space & CSF. So any increase in intracranial pressure is reflected on it & causes optic disc edema (papilloedema). It leaves orbit & enters cranial cavity through optic foramen where it partially decussates with the n. of opposite side, forming optic chiasma.  2)Motor nn. a-Oculomotor (3rd cranial) nerve -Deep origin: Arises from midbrain by 2 nuclei; motor (lat. cell mass & central nucleus) & Parasympathetic (Edinger westphal nucleus). -Superficial attachment & exit from brain: From ant. surface of midbrain in interpeduncular fossa. -Course & end: It passes forwards between post. cerebral & sup. cerebellar aa., then pierces dura infront of decussation point between tentorium free & attached borders. Then it passes in cavernous sinus lat. wall to enter orbit via sup.orbital fissure by 2 divisions; sup. & inf. -Branches: *Sup. division; supplies 2 muscles: sup. rectus & levator palpebrae. *Inf. Division; supplies med. rectus, inf. rectus & inf. oblique. It contains para- sympathetic fibers to ciliary & sphincter pupillae muscles. -Applied anatomy: Oculomotor n. injury produces; 1-Ptosis (upper eyelid drooping) due to levator palpebrae paralysis. 2-Lat. squint due to med. rectus paralysis & unopposed action lat. rectus. 3-Pupil dilatation due to sphincter pupillae paralysis. 4-Loss of accommodation due to ciliary muscle paralysis. Ciliary ganglion Type & site Roots Branches Parasympathetic, *Sensory root: Nasociliary n. 12-15 short ciliary nn. which pierce eyeball back lies near orbital *Sympathetic root: From around optic n. entrance. They contain; apex between sympathetic plexus around I.C.A. *Sensory fibers: Carry eyeball sensation. optic n. & lat. rectus. *Parasympathetic root: *Sympathetic fibers: Supply dilator pupillae & It is suspended Oculomotor n. through n. to eyeball blood vessels. from nasociliary n. inferior oblique. *Parasympathetic postganglionic fibers: Supply ciliary & sphincter pupillae muscles. b-Trochlear (4th cranial) n. c-Abducent (6th cranial) n. Deep origin Trochlear motor nucleus in midbrain. Abducent motor nucleus in pons. Superficial Back of midbrain (Rt. n. comes from Lt. nucleus & vice versa). Lower border pons near midline. attachment & exit from brain Course Curves forwards round midbrain (cerebral peduncle), then Pierces dura at petrous bone apex to & end passes between post. cerebral & sup. cerebellar aa., then enter cavernous sinus cavity & passes pierces dura at decussation point between tentorium free & forwards lat. to I.C.A., then it enters attached borders. Then it passes in cavernous sinus lat. wall orbit through sup. orbital fissure. to enter orbit via sup.orbital fissure. Branches Supplies superior oblique muscle. Supplies lat. rectus muscle. Applied Injury leads to lat. rectus paralysis & med. squint. anatomy  Vessels of orbit A)Ophthalmic a. *Origin: From I.C.A as it leaves cavernous sinus. *Course & end: Enters optic foramen inferolat. to optic n. then becomes lat. to it. In orbit, the a. crosses optic n. from lat. to med. then passes forwards along orbital med. wall between sup. oblique & med. rectus muscles. It ends by dividing into 2 terminal branches; supratrochlear & dorsal nasal aa.. *Branches: 1-Central retinal a.: Most important branch, arises in optic canal behind optic n. & enters optic nerve 1 cm from eyeball, then passes inside it to reach retina. It is an end artery and its obstruction leads to blindness. 2- Lacrimal a.: Largest branch, arises near its exit from optic canal. It passes along orbital lat. side to supply lacrimal gland & upper lid. It gives 2 zygomatic branches one reaches temporal fossa via zygomaticotemporal foramen & the other reaches face via zygomaticofacial foramen. It gives recurrent meningeal branch which passes backwards via lat. part of sup. orbital fissure to anastomose with orbital branch of middle meningeal a. It ends as lateral palpebral aa. which run med. in upper & lower eyelids to anastomose with the med. palpebral aa. 3-Ciliary aa.: *Post. ciliary; long & short, pass to eyeball back & pierce sclera. *Ant. ciliary; from muscular branches, supply iris. 4-Muscular branches: Supply orbital muscles. 5-Supraorbital a.: Arises as ophthalmic a. crosses optic n., supplies upper lid & forehead. 6-Ant. & post. ethmoidal aa.: Pass through ethmoidal foramina to supply ethmoidal air cells. 7-Med. palpebral aa.: 2 arteries supplying upper & lower eyelid, arising from ophthalmic a. termination. 8-Supratrochlear a.: One of the 2 terminal branches, supplies upper lid & forehead. 9-Dorsal nasal a.: The other terminal branch, supplying nose dorsum. B)Ophthalmic vv. 2 in number, formed by union of veins accompanying ophthalmic a. branches. Superior & inf. ophthalmic veins leave orbit through sup. orbital fissure to end in ant. end of cavernous sinus. Central retinal vein ends in cavernous sinus or sup. ophthalmic v.  Eyeball It is embedded in orbital fat, but separated from it by facial sheath called ocular fascia (Tenon’s capsule). This ocular fascia extends from optic n. attachment up to corneoscleral junction. It is thickened around med. & lat. recti tendons & attached to corresponding bones of orbit forming med. & lat. check ligaments. There is fibrous tissue passing between check ligaments called suspensory ligament carrying the eyeball. A)Eyeball wall: 3 coats; 1-Outer coat: *Cornea; transparent ant. part. *Sclera; opaque, formed by dense white fibrous tissue. 2-Middle coat (vascular & pigmented): 3 parts (from post. to ant.); *Choroid; Black membrane, vascular & highly pigmented. *Ciliary body; -Ciliary ring: Shows ridges which are radially arranged. -Ciliary processes: Deep to ciliary muscles & attached to ciliary ring. -Ciliary muscle: Forming muscular ring around iris, it is formed by two parts of smooth muscle fibers; arranged in a meridional & circular direction. These fibers extend from sclera to ciliary processes, when muscle contracts it pulls on these processes so relaxing suspensory ligament of the lens & as a result lens becomes more convex. It is main muscle for accommodation. *Iris; Circular diaphragm between cornea & lens. Perforated at center by pupil. Pigmented & contains circular & radial muscle fibers (involuntary). Circular part forms sphincter pupillae & supplied by parasympathetic fibers, while radial part forms dilator pupillae & supplied by sympathetic fibers. Space between iris & cornea is termed ant. chamber, while space between iris and lens is post. chamber. 3-Inner nervous coat (retina): Consists of outer pigmented & inner nervous parts. From it's ganglionic layer, arises optic n. which pierces eyeball post. pole. B)Eyeball cavity: 1-Aqueous humour: Fluid secreted from vessels of iris & ciliary body, fills ant. & post. eye chambers. 2-Vitreous body: Transparent colourless jelly-like substance filling eye ball post. 5/6. Enveloped by hyaloid membrane. 3-Lens: Transparent biconvex, situated in between iris (in front) & vitreous body (behind). Surrounded by capsule, to which is attached suspensory ligament of lens keeping it in place. C)Eyeball vessels: *Arteries (branches from ophthalmic a.); 1-Ciliary aa.: a)Ant. ciliary aa. b)Long & short post. ciliary aa. 2-Central retinal a. *Veins (drain into ophthalmic vv.); 1-Choroid vv.: Have special arrangement & end in single trunk piercing sclera. 2-Ciliary vv.: Accompany ant. ciliary aa.