TEMPORAL AND INFRATEMPORAL FOSSAE

Objectives List the boundaries and contents of the temporal and infratemporal fossae Describe the articular surfaces, capsule, ligaments and movements of the temporomandibular joint Describe the origin, insertion, action and nerve supply of the muscles of mastication Describe the course, branches and distribution of the mandibular nerve List the types of fibers of the chorda tympani and describe its course Describe the location and connections of the otic ganglion Describe the course of the maxillary artery and list the branches of its first and second parts as well as their distribution Describe the location and communications of the pterygoid venous plexus

Temporal Fossa Boundaries: anterior: zygomatic process of frontal bone and frontal process of zygomatic bone superior and posterior: superior temporal line inferior: zygomatic arch floor: composed of portions of parietal, frontal, greater wing of sphenoid and squamous part of temporal area where 4 bones approach each other is known as pterion. It overlies anterior branch of middle meningeal artery. (laceration of this artery is the most common cause of epidural hematomas)

Temporal Fossa Contents: temporalis muscle and its fascia deep temporal nerves and vessels superficial temporal vessels auriculotemporal nerve zygomaticotemporal nerve and vessels

Infratemporal Fossae

Infratemporal Fossa Boundaries: anterior: infratemporal (posterior) surface of body of maxilla posterior: tympanic part and styloid process of temporal bone medial: lateral pterygoid plate lateral: ramus of mandible superior: infratemporal surface of greater wing of sphenoid has no inferior bony boundary

Infratemporal Fossa Communications: with temporal fossa via space between zygomatic arch and cranial wall with orbit via inferior orbital fissure with middle cranial fossa via foramen ovale and foramen spinosum with pterygopalatine fossa via pterygomaxillary fissure

Contents: lower part of temporalis muscle medial and lateral pterygoid muscles mandibular nerve and its branches chorda tympani otic ganglion maxillary artery and its branches pterygoid venous plexus and maxillary vein

Temporomandibular Joint synovial joint established between mandibular fossa and articular tubercle of temporal bone and head of mandible (mandibular condyle) articular disc: oval plate of fibrous tissue located between temporal and mandibular articular surfaces separates joint into superior and inferior compartments. Peripherally attaches to joint capsule & receives attachment of fibers of lateral pterygoid muscle It moves forward and backward with mandibular condyle. articular capsule: surrounds joint like a sleeve & attaches above to articular tubercle and margins of mandibular fossa & below to neck of mandible

Temporomandibular Joint Ligaments: Lateral (temporomandibular) ligament: strengthens lateral aspect of joint capsule. Fibers pass inferiorly and posteriorly to neck of mandible which limits posterior and inferior displacement of mandibular condyle. Sphenomandibular ligament: lies medial to, and separate, from joint capsule & extends from spine of sphenoid to lingula of mandibular foramen Stylomandibular ligament: lies posteroinferior to and separate from joint capsule. It is a thickening of parotid fascia that extends from styloid process to posterior border of ramus of mandible.

Temporomandibular Joint Nerve supply is derived from branches of mandibular nerve (V3) via the auriculotemporal (main) and masseteric nerves. Blood supply are from branches of superficial temporal and maxillary arteries.

TMJ Movements: elevation and depression protrusion (protraction) and retrusion (retraction) right and left lateral excursions

Muscles of Mastication masseter temporalis medial pterygoid lateral pterygoid all muscles are innervated by branches of mandibular nerve (V3)

Masseter Origin: inferior border and medial surface of zygomatic bone and zygomatic arch Insertion: lateral surface of ramus and angle of mandible Nerve supply: masseteric nerve Main action: elevation of mandible (bilateral contraction)

Temporalis Origin: floor of temporal fossa (some fibers also originate from temporal fascia) Insertion: tendon passes medial to zygomatic arch inserts into coronoid process and anterior border of ramus of mandible Nerve supply: deep temporal nerves (anterior and posterior) Main actions: elevation of mandible (bilateral contraction) retrusion of mandible (bilateral contraction of posterior fibers)

Medial Pterygoid Origin: deep head: medial surface of lateral pterygoid plate superficial head (small): tuberosity of maxilla Insertion: medial surface of ramus and angle of mandible Nerve supply: medial pterygoid nerve Main actions: elevation of mandible (bilateral contraction) lateral excursion of mandible to opposite side of contracting muscle (unilateral contraction)

Lateral Pterygoid Origin: superior head: infratemporal surface of greater wing inferior head: lateral surface of lateral pterygoid plate Insertion: most fibers insert into pterygoid fovea (small depression on anterior aspect of neck of mandible). Some fibers insert into anteromedial aspect of capsule and articular disc of temporomandibular joint. Nerve supply: lateral pterygoid nerve Main actions: protrusion of mandible (bilateral contraction) is necessary to depress mandible lateral excursion of mandible to opposite side of contracting muscle (unilateral contraction)

* Main muscles involved in motions

Mandibular Nerve contains general sensory and motor fibers leaves middle cranial fossa and enters infratemporal fossa via foramen ovale in infratemporal fossa lies deep to lateral pterygoid branches into anterior and posterior divisions branches from main trunk (stem): medial pterygoid nerve supplies medial pterygoid muscle and gives small branches to tensor tympani and tensor veli palatini muscles meningeal branch (nervus spinosus): enters cranial cavity through foramen spinosum supplies dura mater of middle cranial fossa

Mandibular Nerve Branches from anterior division: masseteric nerve: passes through mandibular notch to reach masseter muscle, which it supplies. It also contains a few sensory fibers for anterior aspect of temporomandibular joint. lateral pterygoid nerve: supplies lateral pterygoid muscle deep temporal nerves (anterior and posterior): ascend deep to temporalis muscle to supply it buccal nerve: passes between 2 heads of lateral pterygoid and runs anteriorly and inferiorly  emerges onto cheek from under ramus of mandible  gives sensory innervation to skin and mucosa of cheek

Mandibular Nerve Branches from posterior division: Auriculotemporal nerve: originates by 2 roots that encircle middle meningeal artery and join posterior to it passes posteriorly, medial to lateral pterygoid and neck of mandible  passes posterior to temporomandibular joint  ascends superficial to zygomatic process of temporal bone toward temporal region (with superficial temporal vessels) gives sensory innervation to auricle, external acoustic meatus, tympanic membrane, temporomandibular joint and scalp gives off parotid branches  contain postganglionic parasympathetic fibers from otic ganglion

Mandibular Nerve Branches from posterior division (cont.): 2. Inferior alveolar nerve: contains motor and sensory fibers passes inferiorly, medial to lateral pterygoid, to enter mandibular canal via mandibular foramen & runs within mandibular canal and supplies sensory innervation to all mandibular teeth of corresponding side gives off mental nerve, which emerges onto face via mental foramen & supplies sensory innervation to lower lip and chin before entering mandibular canal it gives off mylohyoid nerve & supplies mylohyoid and anterior belly of digastric muscles

Mandibular Nerve Branches from posterior division (cont.): 3. Lingual nerve: descends medial to lateral pterygoid, anterior to inferior alveolar nerve gives general sensory innervation (touch, pain, temperature) to mucosa of anterior ⅔ of tongue and mucosa of floor of mouth high in infratemporal fossa is joined by chorda tympani (intrapetrosal branch of facial nerve)

Chorda Tympani Intrapetrosal branch of facial nerve (originates from facial nerve within facial canal, just above stylomastoid foramen) & enters tympanic cavity and passes anteriorly across medial surface of tympanic membrane. It exits temporal bone via petrotympanic fissure in infratemporal fossa joins lingual nerve. It contains special sensory fibers (taste) for anterior ⅔ of tongue and preganglionic parasympathetic fibers. Preganglionic parasympathetic fibers terminate in submandibular ganglion which innervate the submandibular submandibular and sublingual salivary glands.

Otic Ganglion Small parasympathetic ganglion located in infratemporal fossa, just inferior to foramen ovale and medial to mandibular nerve. Receives preganglionic parasympathetic fibers from glossopharyngeal nerve via lesser petrosal nerve. Postganglionic parasympathetic fibers leave otic ganglion and join auriculotemporal nerve traveling with auriculotemporal nerve reach parotid gland.

Maxillary Artery Larger terminal branch of external carotid artery. Passes anteriorly, deep to neck of mandible, runs through infratemporal fossa and terminates in pterygopalatine fossa. Parts: mandibular (1st) pterygoid (2nd) pterygopalatine (3rd)

Mandibular (1st) part: extends horizontally forward lies between neck of mandible and sphenomandibular ligament and is accompanied by auriculotemporal nerve and maxillary vein.

Maxillary Artery Branches of mandibular (1st) part: deep auricular artery: supplies external acoustic meatus and outer surface of tympanic membrane anterior tympanic artery: enters tympanic cavity via petrotympanic fissure (with chorda tympani)  supplies mucosa of tympanic cavity middle meningeal artery: passes between two roots of auriculotemporal nerve to enter middle cranial fossa via foramen spinosum. The main artery and its branches lie between bone and dura mater to supplies dura mater and bones of skull

Maxillary Artery Branches of mandibular (1st) part (cont.): 4. Accessory meningeal artery: enters cranial cavity via foramen ovale to supply trigeminal ganglion and adjacent dura mater. 5. Inferior alveolar artery: accompanies inferior alveolar nerve & enters mandibular canal via mandibular foramen. Within mandibular canal gives branches to lower teeth and gingiva and gives off mental artery (exits through mental foramen with corresponding nerve). Before entering mandibular canal, it gives off mylohyoid artery. (accompanies mylohyoid nerve)

Maxillary Artery Pterygoid (2nd) part: Passes anteriorly and superiorly through infratemporal fossa (lateral or medial to lateral pterygoid muscle) Branches (all accompany branches of mandibular nerve): masseteric artery: passes through mandibular notch to supply masseter muscle. deep temporal arteries (anterior and posterior): ascend deep to temporalis muscle to supply it pterygoid arteries: supply medial and lateral pterygoid muscles buccal artery: runs anteriorly and inferiorly toward buccinator muscle  supplies buccinator and skin and mucosa of cheek

Pterygoid Venous Plexus complex venous network located in infratemporal fossa receives veins which correspond with branches of maxillary artery drained posteriorly by maxillary vein & passes posteriorly, medial to neck of mandible to enter the parotid gland which joins superficial temporal vein to form retromandibular vein. communicates with cavernous sinus via emissary veins passing through various foramina (ovale, lacerum) communicates with inferior ophthalmic vein via veins passing through inferior orbital fissure communicates with facial vein via deep facial vein

Case Study A 29 year old male comes to see you on your first day of practice c/o neck pain. You obtain from his history that he was in a car accident approximately 24 hours ago. He is a terrible historian (most patients are) and you are having trouble getting your mind around his story. Finally, he pulls out his wallet to show you some pictures to help you understand. He also states in passing that he has a headache and feels somewhat nauseous. On gross visual examination he has a left periorbital hematoma and a homemade bandage over his left temporal region.

Scene Photos

What the ?????

What are you going to do now? What is your assessment? What questions do you want answers to? Who would you call? What action do you take? What is the prognosis? Early diagnosis vs. late?

Etiology

Epidural Hematoma

Happy Thanksgiving! Be careful out there.