Parotid, Temporal, and Infratemporal Regions

Boundaries of the Temporal Fossa – concavity on lateral cranium which is occupied by temporalis muscle

anterior boundary: posterior surface of the maxilla

posterior boundary: temporal line

superior boundary: part of sphenoid bone located between the base of the lateral pterygoid plate and infratemporal crest

inferior bourndary: frontal, parietal, temporal and greater wing of the sphenoid bone (zygomatic arch)

medial boundary: infratemporal crest (sphenoid and temporal bones)

lateral boundary: zygomatic arch

pterygomaxillary fissure – narrow passage between the maxilla and the lateral pterygoid plate

connects the infratemporal fossa to the pterygopalatine fossa

Boundaries of the Infratemporal Fossa – contains lower portion of temporalis muscle, the lateral and medial pterygoid muscles, ptergoid plexus of veins, the mandibular nerve and its branches, the chroda tympani, and the otic ganglion

anterior boundary: posterior surface of mandible

posterior boundary: anterior surface of the condylar process of the mandible and the styloid process

medial boundary: lateral pterygoid plate of sphenoid bone

lateral boundary: ramus and coronoid process of mandible

roof: infratemporal surface of the greater wing of the sphenoid bone

Communication of the Infratemporal Fossa

foramen ovale and foramen spinosum open to roof of infratemporal fossa

temporal fossa communicates with infratemporal fossa though the foramen formed by the zygomatic arch

infratemporal fossa communicates with orbit via inferior orbital fissure and with pterygopalatine fossa via pterygomaxillary fissure

pterygopalatine fossa communicates with nasal cavity via the sphenopalatine foramen

Blood Supply

Arteries: two terminal branches of external carotid artery Þ superficial temporal artery and maxillary a

maxillary artery: enters infratemp. fossa and exits through pterygomaxillary fissure; divided into 3 regions by lat.pterygoid muscle

Part 1. Between mandible and sphenomandibular ligament; Five Branches:

(1) deep auricular to external acoustic meatus
(2) anterior tympanic to tympanic membrane
(3) middle meningeal enters via foramen spinosum
(4) accessory meningeal to cranial cavity
(5) inferior alveolar to mandible, gingivae and teeth

Part 2. Medial to ramus and temporalis tendon

posterior deep temporal, anterior deep temporal, pterygoid, masseteric and buccal

Part 3. In pterygopalatine fossa lateral to ganglion; Seven Branches:

(1) posterior superior alveolar

(2) middle superior alveolar

(3) infraorbital

(4) descending palatine

(5) artery of pterygoid canal

(6) pharyngeal

(7) sphenopalatine

terminal branches of maxillary artery: infraorbital artery (enters inferior orbital fissure) and phenopalatine artery (enters nasal cavity via sphenopalatine foramen)

branches of the external carotid artery: "Some Angry Lady Figured Out PMS" Superior thyroid, Ascending pharyngeal, Lingual, Facial, Occipital, Posterior auricular, Maxillary, Superficial temporal

Veins: pterygoid venous plexus

Innervation

Trigeminal Nerve: "Standing Room Only": V1: superior orbital fissure; V2: foramen rotundum; V3: foramen ovale

(1) Motor: trigeminal motor nucleus Þ trigeminal ganglion Þ mandibluar division (V3) Þ masseter, temporalis, pterygoids, mylohyoid anterior belly of digastric, tensor tympani, tensor veli palatini

(2) Proprioception: mesencephalic trigeminal nucleus Þ trigeminal ganglion Þ maxillary (V2) and mandibular division (V3)

Mandibular Nerve: all nerves to the infratemporal region except the chorda tympani, a branch of CN VII, are derived from the mandibular nerve (V3)

enters via foramen ovale;
sensory and motor fibers; supplies four muscles of mastication

Four Branches of Mandibular Nerve

(1) Auriculotemporal Nerve: enters mandibular foramen, passes through mandibular canal and exits mental foramen as mental nerve

supplies teeth on mandible, skin and mucus membrane of lower lip, chin and vestibular gingiva of mandibular incisors
carries both parasympathetic and sympathetic fibers to the parotid gland

(2) Lingual Nerve: lies anterior to inferior alveolar nerve and runs with chorda tympani

sensory to anterior 2/3 of tongue, floor of mouth, and gingiva

(3) Buccal Nerve: runs between two heads of lateral pterygoid muscle

sensory fibers to skin and mucous membrane of cheek and mandibular buccal gingiva molar region

(4) Inferior Alveolar: enters mandibular canal through mandibular foramen

gives rise to mylohyoid, inferior dental branch, mental, and incisive branch

Otic Ganglion: parasympathetic ganglion located in infratemporal fossa

Chorda tympani: branch of facial nerve; supplies parasympathetic fibers to submandibular and sublingual salivary

glands and taste to anterior 2/3 of tongue
arises from facial nerve within the facial canal, passes through middle ear and leaves skull through petrotympanic fissure
joins lingual nerve in infratemporal region

Parasympathetic Pathways to Temporal Region Glands

Parotid Salivary Gland: inferior nucleus salvatorius, glosssopharyngeal IX, lessor petrosal, otic ganglion, auriculotemporal

Submandibular and Sublingual Salivary Glands: superior nucleus salvatorius, facial VII, geniculate ganglion, chorda tympani, lingual submandibular ganglion

Lacrimal Gland: superior nucleus salvatorius, greater petrosal, pterygopalatine ganglion, maxillary, zygomatic, lacrimal

Parotid – largest of 3 salivary glands; occupies retromandibular space between ramus of mandible and mastoid process

wraps around posterior edge of angle of mandible to lie anterior to stylohyoid muscle and posterior belly of digastric muscle
internal structures: retromandibular vein travels within deep part of gland; facial nerve travels within superficial part

Stensen’s Duct: duct of parotid, crosses masseter and pierces buccinator and opens into oral cavity
Lymph: drains to superficial and deep cervical lymph nodes

Tempormandibular Joint – synovial joint between the articular tubercle of the temporal bone and the mandibular fossa of mandible; divided by articular disk

temporomandibular ligament – extends from tubercle on zygoma to the neck of the mandible

sphenomandibular ligament – extends from the spine of the sphenoid bone to the lingula of the mandible

Temporomandibular Joint: Four Muscles of Mastication – All supplied by motor root of mandibular nerve (V3)

Masseter

Origin: zygomatic arch

Insertion: lateral and posterior aspect of the mandibular ramus

Nerve: Trigeminal

Action: Elevates mandible

Temporalis

Origin: temporalis fascia and cranium above zygomatic arch

Insertion: medal surface of the angle of the mandible

Nerve: Trigeminal

Action: Elevates mandible

Medial pterygoid

Origin: tuberosity of maxilla, medial surface of lateral pterygoid plate

Insertion: medial surface of angle of ramus of mandible

Nerve: Trigeminal

Action: Elevates mandible

Lateral pterygoid

Origin: lateral surface of the lateral pterygoid plate

Insertion: neck of mandible

Nerve: Trigeminal

Action: Open jaw

Digastric

Origin: Anterior belly from digastric fossa of mandible; posterior belly from mastoid notch

Insertion: Intermediate tendon attached to body of hyoid

Nerve:

Posterior belly: facial nerve;

Anterior belly:mylohyoid nerve of trigeminal nerve

Stylohyoid

Origin: Styloid process

Insertion: Body of hyoid

Nerve: Facial

Action: Elevates hyoid

Chewing – depression of mandible and protraction of mandibular head to articular tubercle

articular capsule prevents overextension
center of rotation established on non-chewing (balancing) side