Temporal Region

ƒ The temporal region includes the temporal and infratemporal fossae, superior and inferior to the zygomatic arch, respectively Temporal fossa ƒ In which the temporal muscle (L. temporalis) is located ƒ Is bounded : à Posteriorly and superiorly by the temporal lines à Anteriorly by the frontal and zygomatic bones à Laterally by the zygomatic arch à Inferiorly by the infratemporal crest à Floor by frontal, parietal, temporal, and greater wing of the sphenoid (bone of pterion) à Roof by the temporal fascia

Temporal fossa

ƒ Temporal fascia covers the temporal muscle, attaching superiorly to the superior temporal line. Inferiorly, the fascia splits into two layers, which attach to the lateral and medial surfaces of the zygomatic arch. ƒ The temporal fascia also tethers the zygomatic arch superiorly. When the powerful masseter muscle, which is attached to the inferior border of the arch, contracts and exerts a strong downward pull on the arch, the temporal fascia provides resistance.

Temporal fossa

Contents: 1. Temporalis ms arises from the bony floor and the overlying temporal fascia 2. Superficial temporal nerve and vessels 3. Deep temporal nerve and vessels 4. auriculotemporal nerve Infratemporal fossa

ƒ is an irregularly shaped space deep and inferior to the zygomatic arch, deep to the ramus of the mandible and posterior to the maxilla. ƒ It communicates with the temporal fossa through the interval between (deep to) the zygomatic arch and (superficial to) the cranial bones. Infratemporal fossa- Boundaries ƒ Lateral = ramus of mandible ƒ Medial = lateral pterygoid plate ƒ Anterior = posterior aspect of maxilla ƒ Posterior = tympanic plate and the mastoid & styloid process of temporal bone. ƒ Superior = infratemporal surface of the greater wing of sphenoid bone. ƒ Inferior = medial pterygoid muscle attaches to the mandible near the angle

Infratemporal fossa, contents.

ƒ Inferior part of the temporal muscle ƒ Lateral and Medial Pterygoid muscle ƒ Maxillary artery (2nd part) and its branches ƒ Pterygoid venous plexus ƒ Mandibular nerve and its branches : à inferior alveolar à lingual à buccal ƒ Otic Ganglion ƒ chorda tympani nerve , from facial nerve

Maxillary artery

ƒ The maxillary artery is the larger of the two terminal branches of the external carotid artery ƒ It arises posterior to the neck of the mandible and is divided into three parts based on its relation to the lateral pterygoid muscle.

Course of 1st partBranches Distribution Proximal Deep auricular Supplies external acoustic meatus, external (posterior) to artery tympanic membrane, and temporomandibular joint lateral pterygoid Anterior tympanic Supplies internal aspect of tympanic muscle; runs artery membrane horizontally, deep Middle meningeal Enters cranial cavity via foramen spinosum to (medial) to neck artery supply periosteum, bone, red bone marrow, of condylar dura mater of lateral wall and calvaria of process of neurocranium, trigeminal ganglion, facial nerve and geniculate ganglion, tympanic mandible and cavity, and tensor tympani muscle lateral to stylomandibular Accessory Enters cranial cavity via foramen ovale; its ligament meningeal artery distribution is mainly extracranial to muscles of infratemporal fossa, sphenoid bone, mandibular nerve, and otic ganglion

Inferior alveolar Descends to enter mandibular canal of artery mandible via mandibular foramen; supplies mandible, mandibular teeth, chin, mylohyoid Course fo 2nd part Branches Distribution Adjacent (superficial Masseteric artery Traverses mandibular notch, or deep) to lateral supplying temporomandibular pterygoid muscle; joint and masseter ascends obliquely anterosuperiorly, Deep temporal Anterior and posterior arteries medial to temporal arteries ascend between temporal muscle muscle and bone of temporal fossa, supplying mainly muscle

Pterygoid branches Irregular in number and origin; supply pterygoid muscle

Buccal artery Runs anteroinferiorly with buccal nerve to supply buccal fat-pad, buccinator, and buccal oral mucosa Infratemporal fossa, contents ƒ The pterygoid venous plexus: à is located partly between the temporal and the pterygoid muscles. à It is the venous equivalent of most of the maxillary artery ,that is, most of the veins that accompany the branches of the maxillary artery drain into this plexus. à Anastomoses anteriorly with the facial vein via the deep facial vein and superiorly with the cavernous sinus via emissary veins. à The extensive nature and volume of this plexus is difficult to appreciate in the cadaver Infratemporal fossa, contents

ƒ The mandibular nerve descends through the foramen ovale into the infratemporal fossa and divides into sensory and motor branches.

ƒ The branches of CN V3 are the auriculotemporal, inferior alveolar, lingual, and buccal nerves.

ƒ Branches of the CN V3 also supply the four muscles of mastication but not the buccinator, which is supplied by the facial nerve. Infratemporal fossa, contents ƒ The otic ganglion (parasympathetic): à Is located in the infratemporal fossa, just inferior

to the foramen ovale, medial to CN V3 and posterior to the medial pterygoid muscle. à Presynaptic parasympathetic fibers, derived mainly from the glossopharyngeal nerve, synapse in the otic ganglion. à Postsynaptic parasympathetic fibers, which are secretory to the parotid gland, pass from the otic ganglion to this gland through the auriculotemporal nerve. Infratemporal fossa, contents ƒ The auriculotemporal nerve: à Encircles the middle meningeal artery à Divides into numerous branches, the largest of which passes posteriorly, medial to the neck of the mandible, and supplies sensory fibers to the auricle and temporal region. à Also sends articular fibers to the TMJ and parasympathetic secretomotor fibers to the parotid gland. ƒ The inferior alveolar nerve: à Enters the mandibular foramen and passes through the mandibular canal, forming the inferior dental plexus, which sends branches to all mandibular teeth on its side. à Another branch of the plexus, the mental nerve, passes through the mental foramen and supplies the skin and mucous membrane of the lower lip, the skin of the chin, and the vestibular gingiva of the mandibular incisor teeth. Infratemporal fossa, contents

ƒ The lingual nerve: à lies anterior to the inferior alveolar nerve. à sensory to the anterior two thirds of the tongue, the floor of the mouth, and the lingual gingivae. à Enters the mouth between the medial pterygoid muscle and the ramus of the mandible and passes anteriorly under cover of the oral mucosa, just inferior to the 3rd molar tooth. ƒ The chorda tympani nerve: à branch of CN VII carrying taste fibers from the anterior two thirds of the tongue, joins the lingual nerve in the infratemporal fossa . à Also carries secretomotor fibers for the submandibular and sublingual salivary glands. Infratemporal fossa, clinical ƒ Mandibular Nerve Block à An anesthetic agent is injected near the mandibular nerve where it enters the infratemporal fossa. In the extraoral approach, the needle passes through the mandibular notch of the ramus of the mandible into the infratemporal fossa. The injection usually anesthetizes the auriculotemporal, inferior alveolar, lingual, and buccal branches of CN V3. ƒ Inferior Alveolar Nerve Block

à Anesthetizes the inferior alveolar nerve, a branch of CN V3. The site of the anesthetic injection is around the mandibular foramen, the opening into the mandibular canal on the medial aspect of the ramus of the mandible. This canal gives passage to the inferior alveolar nerve, artery, and vein. When this nerve block is successful, all mandibular teeth are anesthetized to the median plane. The skin and mucous membrane of the lower lip, the labial alveolar mucosa and gingivae, and the skin of the chin are also anesthetized because they are supplied by the mental nerve, a branch of the inferior alveolar nerve.

Pterygopalatine fossa ƒ A small pyramidal space inferior to the apex of the Orbit. ƒ Lies between the pterygoid process of the sphenoid posteriorly and the posterior aspect of the maxilla anteriorly. ƒ Is a major distributing center for branches of the maxillary nerve and the pterygopalatine (third) part of the maxillary artery. ƒ Boundaries: à Medial wall = vertical plate of palatine bone à Roof (incomplete)= greater wing of the sphenoid bone à Floor = pyramidal process of the palatine bone à Superior larger end opens into the inferior orbital fissure à Inferior end is closed except the palatine foramina

Pterygopalatine fossa ƒ It is located between, and has communications with, the infratemporal fossa, nasal cavity, orbit, middle cranial fossa, pharyngeal vault, maxillary sinus, and oral cavity (palate) ƒ It communicates with the following: à Laterally thru the pterygomaxillary fissure= infratemporal fossa à Medially thru sphenopalatine foramen = nasal cavity à Anterosuperiorly thru inferior orbital fissure = Orbit. à Posterosuperiorly thru foramen rotundum and pterygoid canal = Middle cranial fossa. ƒ The fossa has been exposed through the floor of the orbit and maxillary sinus. The foramen rotundum, pterygoid canal, and pharyngeal canal are openings in the posterior wall of the pterygopalatine fossa. Pterygopalatine fossa , contents

ƒ Contents: 1. Terminal 3rd or the pterygopalatine part of the maxillary artery and branches. +accompaning veins 2. Maxillary nerve ( enters thru the foramen rotundum) and branches: à Zygomatic Nerves ‚ Zygomaticofacial + zygomaticotemporal nerves à Pterygopalatine nerves 3. Nerve of the pterygoid canal. 4. Pterygopalatine ganglion. 5. Surrounding fatty matrix Third part Branches Distribution Distal Posterior Descends on maxilla's infratemporal (anteromedial) to superior surface with branches traversing lateral pterygoid alveolar artery alveolar canals to supply maxillary muscle; passes molar and premolar teeth, adjacent between heads of gingiva, and mucous membrane of lateral pterygoid maxillary sinus and through Infraorbital Traverses inferior orbital fissure, pterygomaxillary artery infraorbital groove, canal, and foramen; fissure into supplies inferior oblique and rectus pterygopalatine muscles, lacrimal sac, maxillary fossa canines and incisors teeth, mucous membrane of the maxillary sinus, and skin of infraorbital region of face Artery of Passes posteriorly through pterygoid pterygoid canal; supplies mucosa of upper canal pharynx, pharyngotympanic tube, and tympanic cavity Third part Branches Distribution

Pharyngeal branchPasses through palatovaginal canal to supply mucosa of nasal roof, nasopharynx, sphenoidal air sinus, and pharyngotympanic tube

Descending Descends through palatine canal, dividing palatine artery into greater and lesser palatine arteries to mucosa and glands of hard and soft palate

Sphenopalatine Terminal branch of maxillary artery, artery traverses sphenopalatine foramen to supply walls and septum of nasal cavity; frontal, ethmoidal, sphenoid, and maxillary sinuses; and anteriormost palate as posterior lateral nasal + posterior septal branches

ƒ The maxillary nerve: à enters the fossa through the foramen rotundum and runs anterolaterally in the posterior part of the fossa . à Within it, it gives off the zygomatic nerve, which divides into zygomaticofacial and zygomaticotemporal nerves . These nerves emerge from the zygomatic bone through cranial foramina of the same name and supply general sensation to the lateral region of the cheek and temple. ‚ The zygomaticotemporal nerve also gives rise to a communicating branch, which conveys parasympathetic secretomotor fibers to the lacrimal gland by way of the heretofore purely sensory lacrimal nerve

from CN V1 . à Also gives off the two pterygopalatine nerves that suspend the parasympathetic pterygopalatine ganglion in the superior part of the pterygopalatine fossa . These nerves convey general sensory fibers of the maxillary nerve, which pass through the pterygopalatine ganglion without synapsing and supply the nose, palate, tonsil, and gingivae. à The maxillary nerve leaves the pterygopalatine fossa through the inferior orbital fissure, after which it is known as the infraorbital nerve.

ƒ The parasympathetic fibers to the pterygopalatine ganglion come from the facial nerve by way of its first branch, the greater petrosal nerve . This nerve joins the deep petrosal nerve as it passes through the foramen lacerum to form the nerve of the pterygoid canal, which passes anteriorly through this canal to the pterygopalatine fossa. The parasympathetic fibers of the greater petrosal nerve synapse in the pterygopalatine ganglion. ƒ The deep petrosal nerve is a sympathetic nerve arising from the internal carotid plexus as the artery exits the carotid canal. It conveys postsynaptic fibers from nerve cell bodies in the superior cervical sympathetic ganglion to the pterygopalatine ganglion by joining the nerve to the pterygoid canal. The fibers do not synapse in the

ganglion but pass directly through it into the branches (of CN V2) arising from it. ƒ The postsynaptic parasympathetic and the sympathetic fibers pass to the lacrimal gland, the palatine glands, and the mucosal glands of the nasal cavity and superior pharynx.

External Cranial Fossae Cranial Fossae