Temporal & Infratemporal Region -I

Temporal & Infratemporal Region

1. Temporal & Infratemporal Regions -I Dr. Prabhakar Yadav Associate Professor Department of Human Anatomy B.P. Koirala Institute of Health Sciences

2. Teporal Fossa : Boundaries : Anterior: Zygomatic & Frontal bones Posterior: Inferior temporal line & supramastoid crest Superior: Superior temporal line Inferior: Zygomatic arch Floor: Parts of frontal, Parietal, Temporal & greater wing of Sphenoid Pterion : lies in anterior part of floor where frontal , parietal , squamous temporal and greater wing of sphenoid meet at an H-shaped suture. Zygomatic arch: formed Anteriorly by-- Temporal process of zygomatic bone & Posteriorly by-- Zygomatic process or zygoma of temporal bone.

3. Contents: Temporal fascia Temporalis muscle ( attached to floor & inferior temporal line) Middle temporal artery ( branch of superficial temporal art.) Zygomaticotemopral nerve & artery Deep temporal nerve Deep temporal artery Deep temporal artery Deep temporal nerve Zygomaticotemopral nerve Middle temporal artery

4. Infratemporal fossa : Lies below the skull, behind the body of maxilla & lateral to lateral pterygoid plate . Boundaries: Anterior: Posterior surface of body of maxilla & medial surface of Zygomatic bone. Roof: Infra temporal surface of greater wing of sphenoid. Medial: Lateral pterygoid plate & pyramidal process of palatine bone Lateral: Ramus of mandible Floor & posterior wall: Open Temporal fossa communicates with infratemporal fossa through a gap deep to zygomatic arch.

5. Contents: 1. Lateral pterygoid muscle; Medial pterygoid muscle 2. Mandibular nerv e & its branches 3. Maxillary nerve with post. Superior alveolar nerve 4. Chorda tympani nerve 5. 1 st & 2 nd part of maxillary artery with their branches 6. Posterior superior alveolar artery ( br. Of 3 rd part of maxillary artery) 7. Accompanying veins .

6. MUSCLES OF MASTICATION: Masseter , Temporalis , Lateral & Medial pterygoid develop from first branchial arch,-supplied by mandibular nerve Temporalis : Origin : ( a)Temporal fossa ( b) Temporal Fascia Fibres pass through gap deep to zygomatic arch Insertion : (a) Margins and deep surface of coronoid process (b) Anterior border of ramus of mandible Nerve supply : Two deep temporal nerve- branches from anterior division of mandibular nerve Actions: (a) Elevates mandible (b) Posterior fibres retract the protruded mandible ( c) Helps in side to side grinding movement

7. Masseter : Origin: (a) Superficial ayer - Anterior 2/3 of lower border of zygomatic arch & adjoining zygomatic process of maxilla (b) Middle layer : p osterior 1/3 rd of lower border of zygomatic arch (c) Deep layer: from deep surface of zygomatic arch Insertion: (a) superficial layer: lower part of lateral surface of ramus of mandible (b) Middle layer: central part of ramus of mandible (c )Deep layer: upper part of the ramus of mandible & coronoid process Nerve supply: Masseteric Nerve Action: Elevates mandible to close mouth superficial fibres - protrusion

8. Lateral Pterygoid : Origin: upper (small) head: infratemporal surface & crest of greater wing of sphenoid L ower ( l arge) head: lateral surface of lateral pterygoid plate Insertion: Pterygoid fovea, Articular disc & capsule of temporomandibular joint. Nerve supply : nerve to latral pterygoid - branch of anterior division of mandibular nerve . Actions 1. Lateral pterygoids of two sides depress the mandible 2. Lateral and medial pterygoid muscles of two sides acting together protrude the mandible. 3. Lateral and medial pterygoid muscles of the two sides contract alternately to produce side-to-side movements of the lower jaw as in chewing.

9. Medial Pterygoid : Origin: S uperficial ( s mall) head: Maxillary tuberosity & lateral surface of pyramidal process of palatine bone Deep (large) head: Medial surface of lateral pterygoid plate & pyramidal process of palatine bone. Insertion: R oughened area on posteroinferior part of medial surface & angle of ramus of mandible. Nerve supply: nerve to medial pterygoid Actions 1.Medial pterygoids of two sides elevates mandible 2.Acting with lateral pterygoids protrude mandible 3. Lateral and medial pterygoids of two sides contract alternately to produce side-to-side movements

10. T emporal fascia: Thick aponeurotic sheet- covers temporalis muscle. Superiorly: single layered - attached to superior temporal line. Inferiorly : Two layers- attached to inner and outer lips of upper border of the zygomatic arch . G ap contains fat, Middle temporal artery- branch from superficial temporal artery & zygomatico -temporal nerve. superficial surface receives an expansion from epicranial aponeurosis . Superficial surface gives origin to auricularis anterior and superior. Deep surface gives origin to some fibres of temporalis muscle.

11. Relations of lateral pterygoid : key muscle of infratemporal region Superficial relation : 1. Masseter. 2. Ramus of the mandible. 3 . Tendon of temporalis . 4. Superficial head of medial pterygoid . 5. Maxillary artery and its temporal & masseteric branches.

12. Deep: 1. Mandibular nerve. 2. Middle meningeal artery. 3. Sphenomandibular ligament. 4. Deep head of medial pterygoid muscle. Pterygoid plexus of veins surrounds the lateral pterygoid .

13. Structures emerging at upper border: 1. Deep temporal nerves (two in number). 2. Masseteric nerve Structures emerging at lower border : 1. Inferior alveolar nerve and artery. 2. Lingual nerve. 3. Middle meningeal artery (it passes up deep to the lower border). Structures passing through gap between two heads: 1. Maxillary artery- enter to reach pterygopalatine fossa through pterygomaxillary fissure. 2. Buccal branch of mandibular nerve- leave to provide sensory innervation to skin & mucus membrane of the cheek.

14. Relations of Medial pterygoid : Superficial : 1. Lingual nerve. 2. Inferior alveolar nerve. 3. Inferior alveolar vessels . 4. Lateral pterygoid plate Deep: 1. T ensor veli palatini & Levator veli palatini 2. Superior constrictor of pharynx. 3. Styloglossus and stylopharyngeus muscles.

15. MAXILLARY ARTERY: arises behind neck of mandible. S upplies : (a) Dura mater ( b) E xternal & Middle ears & auditory tube; ( c) u pper and lower jaws; ( d)Muscles Of temporal and infratemporal regions; (e) Nose & paranasal air sinuses; (f) P alate & ( g) R oot of pharynx Course and Relations: Divided into three parts by lateral pterygoid . First ( mandibular ) part : runs horizontally , first between neck of mandible & sphenoniandibular ligament, and then along lower border of lateral pterygoid . second ( pterygoid ) part : runs upwards & forwards superficial to lower head of lateral pterygoid Third ( pterygopalatine ) part : passes between two heads of lateral pterygoid & through pterygomaxillary fissure, to enter pterygopalatine fossa .

16. Branches from the First Part: 1. Deep auricular artery- supplies: (a) skin of external acoustic meatus , and (b) outer surfaces of tympanic membrane . (c) TMJ 2. Anterior tympanic artery- supplies inner surface of the tympanic membrane & middle ear 3. Middle meningeal artery- Supplies meninges as well as the skull bone -Artery ascends upwards deep to lateral pterygoid - Enter cranial cavity through foramen spinosum . -on the greater wing of sphenoid, it divides into frontal and parietal branches. -Middle meningeal artery and its branches lie outside dura and deep to inner surface of skull . Both are supplied by artery .

17. 4. Accessory middle meningeal artery: supplies meninges & structures in infratemporal fossa . 5. Inferior alveolar/dental artery- supplies Molar & premolar teeth and adjoining gum. Before entering the mandibular foramen, inferior alveolar artery gives off two branches (a) Lingual branch : accompanies lingual nerve - supply mucous membrane of the cheek . (b) Mylohyoid branch : supplies mylohyoid muscle. It also gives off mental and incisive branches. Incisive branch: supplies canine and incisor Mental branch : supply skin of chin

18. Branches from Second Part Deep temporal arteries (usually two in number ): supply- temporalis muscle Pterygoid branches Supply- medial & lateral pterygoid muscles . Masseteric artery— supplie s the masseter muscle. Buccal artery — supplies buccinator muscle

19. Branches from Third Part Posterior superior alveolar artery: Supply- Molar & premolar teeth & mucus membrane of maxillary air sinus . Infraorbital artery: gives the following branches : In the orbit : (a) Some branches to orbital contents. (b) Middle superior alveolar artery to premolar teeth . (c) Anterior superior alveolar artery - supplies- maxillary air sinus ,canine & incisor of upper jaw . In the face : Branches to supply lacrimal sac , medial angle of eye , side of nose & upper lip . Greater palatine artery: supplies roof of the mouth & adjoining gum, In greater palatine canal artery gives off lesser palatine arteries that emerge through lesser palatine foramina and supply soft palate & tonsil

20. Pharyngeal artery: Supplies- mucus membrane of nasopharynx , auditory tube, sphenoidal air sinus . Artery of pterygoid canal: supplies - pharynx, auditory tube & tympanic cavity . Sphenopalatine artery: continuation of maxillary art. Enters nasal cavity in posterior part of superior meatus through sphenopalatine foramen. Here it divides into: (a) posterior lateral nasal branch Supply- lateral wall of nose; Sphenoidal & ethmoidal air sinuses (b ) posterior septal /medial branches Supply- nasal septum Sphenopalatine artery- artery of epistaxis

21. Pterygoid Plexus of Veins: L ies around and within lateral pterygoid muscle Tributaries of plexus correspond to branches of maxillary artery Plexus is drained by maxillary vein(formed at lower border of lateral pterygoid muscle) which unites with superficial temporal vein to form retromandibular vein. Maxillary vein accompanies only first part of maxillary artery . pterygoid venous plexus communicates with : (a) Inferior ophthalmic vein via inferior orbital fissure, ( b)cavernous sinus by emissary veins via foramen Ovale . (c) Facial vein through deep facial vein

22. PTERYGOPALATINE FOSSA: Pyramidal Space between body of maxilla & root of pterygoid process, lateral to perpendicular plate of palatine bone. BOUNDARIES: Anterior : superomedial part of posterior surface of maxilla . Posterior: Root of Pterygoid process and adjoining part of anterior surface of the greater wing of sphenoid. Medial: Upper part of perpendicular plate of palatine . orbital and sphenoidal process of palatine. Lateral : Fossa opens into infratemporal fossa through pterygomaxillary fissure. Superior: Under surface of body of sphenoid Inferior : Pyramidal process of the palatine bone (in the angle between maxilla and pterygoid process)

23. COMMUNICATIONS: Anteriorly: With orbit through medial end of inferior orbital fissure . Posteriorly : 1. With middle cranial fossa via foramen rotundum . 2 . With foramen lacerum via pterygoid canal . 3 . With pharynx via palatovaginal (pharyngeal) canal. Medially: With nose through sphenopalatine foramen . Laterally : With infratemporal fossa via P terygomaxillary fissure . Inferiorly: With oral cavity via greater palatine canals

24. CONTENTS: 1. Maxillary nerve. 2. Pterygopalatine ganglion. 3. Third part of the maxillary artery .

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