INFRATEMPORAL FOSSA

Dr. Mohammed Mahmoud Mosaed

INFRATEMPORAL FOSSA

• Site: it lies deep to the

ramus of the mandible.

• Communications: It

communicates with the

temporal fossa deep to the

zygomatic arch and the

pterygopalatine fossa

through the

pterygomaxillary fissure

Boundaries• The infratemporal fossa has a roof, and

lateral and medial walls, and is open to the

neck posteroinferiorly, i.e. the fossa has no

anatomical floor

• The roof is formed by the infratemporal

surfaces of the temporal bone and of the

greater wing of the sphenoid, and contains

the foramena ovale and spinosum and the

petrotympanic fissure: it is open superiorly to

the temporal fossa

Boundaries• The medial wall is formed anteriorly by the

lateral pterygoid plate of the pterygoid process

of the sphenoid, and more postero-medially by

the pharynx and tensor and levator veli

palatini. It contains the pterygomaxillary fissure

across which structures pass between the

infratemporal and pterygopalatine fossae

• The lateral wall is formed by the medial

surface of the ramus of the mandible.

Contents

• The major structures that occupy the

infratemporal fossa are:

– The lateral and medial pterygoid muscles,

– The mandibular division of the trigeminal nerve,

– The chorda tympani branch of the facial nerve,

– The otic parasympathetic ganglion,

– The maxillary artery

– The pterygoid venous plexus

• The mandibular nerve is the largest of the three divisions of thetrigeminal nerve.

• Mandibular nerve is both motor and sensory.

• It carries :

• General sensation from the teeth and gingivae of the mandible,the anterior two-thirds of the tongue, mucosa on the floor ofthe oral cavity, the lower lip, skin over the temple and lowerface, and part of the cranial dura mater.

• Motor innervation

• to the muscles of mastication, mylohyoid and anterior belly ofdigastric muscle

• to one of the muscles (tensor tympani) in the middle ear, andone of the muscles of the soft palate (tensor veli palatini).

Mandibular nerve

• All branches of the mandibular nerve originate in theinfratemporal fossa.

• The sensory part of the mandibular nerve

• originates from the trigeminal ganglion in the middlecranial fossa:

• It passes vertically through the foramen ovale andenters the infratemporal fossa between the tensorveli palatini muscle and the upper head of the lateralpterygoid muscle;

• The small motor root of the trigeminal nerve

• passes medial to the trigeminal ganglion in the cranialcavity, then passes through the foramen ovale andimmediately joins the sensory part of the mandibularnerve.

• Branches:

• Soon after the sensory and motor roots join, themandibular nerve gives rise to a small meningealbranch and nerve to medial pterygoid, and thendivides into anterior and posterior trunks:

• Branches from the anterior trunk are the buccal,masseteric, and deep temporal nerves, and the nerveto lateral pterygoid, all of which are motor nerves,except the buccal nerve which is sensory.

• Branches from the posterior trunk are theauriculotemporal, lingual, and inferior alveolar nerves,all of which, are sensory nerves except nerve tomylohyoid that branches from the inferior alveolarnerve which is motor

Branches of the trunk of mandibular nerve

• Meningeal branch (nervous spinosus)

• Ascends with the middle meningeal artery and re-enter the cranial cavity through the foramenspinosum.

• Nerve to medial pterygoid

• It enters and supplies the deep surface of themedial pterygoid muscle.

• It has two small branches:

• One supplies the tensor veli palatini;

• One to the tensor tympani muscle

Branches of anterior division • Buccal nerve

• A branch of the anterior trunk of the mandibular nerve. It is a sensory nerve,

• It passes laterally between the upper and lower heads of lateral pterygoid to theanterior margin of the ramus of mandible.

• It continues into the cheek lateral to the buccinator muscle to supply generalsensory nerves to the adjacent skin and oral mucosa.

• Masseteric nerve

• It is a branch of the anterior trunk of the mandibular nerve.

• It passes through the mandibular notch to penetrate and supply the massetermuscle.

• Deep temporal nerves

• Usually two in number, originate from the anterior trunk of the mandibular nerve.They ascend in the temporal fossa and supply the temporalis muscle from itsdeep surface

• Nerve to lateral pterygoid

• It originate directly as a branch from the anterior trunk of the mandibular nerve .

• It passes directly into the deep surface of the lateral pterygoid muscle.

Branches of the posterior division

• Auriculotemporal nerve

• Lingual nerve

• Inferior alveolar nerve

Auriculotemporal nerve • It is the first branch of the posterior division of the

mandibular nerve and originates as two roots, whichpass posteriorly around the middle meningeal artery.

• It curves laterally around the neck of mandible andthen ascends deep to the parotid gland between thetemporomandibular joint and ear.

• It carry general sensation from skin over a large areaof the temple.

• Sensory innervation of the external ear, the externalauditory meatus, tympanic membrane, andtemporomandibular joint.

• It also delivers postganglionic parasympathetic nervesfrom the glossopharyngeal nerve to the parotid gland.

Lingual nerve • It is the sensory branch of the posterior trunk of the

mandibular nerve.

• The lingual nerve first descends between the tensor velipalatini muscle and the lateral pterygoid muscle, where it isjoined by the chorda tympani nerve, and then descendsacross the lateral surface of the medial pterygoid muscle toenter the oral cavity.

• As the lingual nerve passes on the medial surface of themandible immediately inferior to the last molar tooth.

• It is in danger when operating on the molar teeth andgingivae.

• The lingual nerve passes into the tongue on the lateralsurface of the hyoglossus muscle where it is attached to thesubmandibular ganglion.

• The lingual nerve carries general sensation fromthe anterior two-thirds of the tongue, oralmucosa on the floor of the oral cavity, and lingualgingivae associated with the lower teeth.

• The lingual nerve is joined by the chorda tympanibranch of the facial nerve, which carries:

• Taste from the anterior two-thirds of the tongue.

• Parasympathetic fibers to all salivary glandsbelow the level of the oral fissure.

Inferior alveolar nerve • It is a major sensory branch of the mandibular nerve.• It innervates all lower teeth and gingivae, the mucosa and

skin of the lower lip and skin of the chin.• It has one motor branch, which innervates the mylohyoid

muscle and the anterior belly of the digastric muscle.• It descends and then enters the mandibular canal through

the mandibular foramen.• Just before entering the mandibular foramen, it gives the

nerve to mylohyoid, to innervate the mylohyoid muscle andthe anterior belly of the digastric muscle.

• The inferior alveolar nerve passes anteriorly within themandibular canal of the lower jaw.

• It supplies molar and second premolar teeth and associatedlabial gingivae, and then divides into its two terminalbranches: the incisive nerve and the mental nerve.

Chorda tympani nerve• The chorda tympani originates from the facial

nerve.

• The chorda tympani carries taste from the anteriortwo-thirds of the tongue and parasympatheticinnervation to all salivary glands below the level ofthe oral fissure.

• It enters the infratemporal fossa, and joins thelingual nerve.

• Preganglionic parasympathetic fibers carried in thechorda tympani synapse in the submandibularganglion, which 'hangs off' the lingual nerve in thefloor of the oral cavity.

Lesser petrosal nerve • The lesser petrosal nerve is a branch of the tympanic plexus in the middle

ear, which had its origin from a branch of the glossopharyngeal nerve.• It carries mainly parasympathetic fibers for the parotid gland.• The tympanic nerve which is branch from the glossopharyngeal nerve

enters the middle ear to participates in the formation of the tympanicplexus on the promontory of the middle ear.

• The lesser petrosal nerve is a branch of this plexus.• The lesser petrosal nerve contains mainly preganglionic parasympathetic

fibers.• It leaves the middle ear and enters the middle cranial fossa through a

small opening on the anterior surface of the petrous part of the temporalbone.

• The lesser petrosal nerve then passes through the foramen ovale with themandibular nerve.

• In the infratemporal fossa it synapse in the otic ganglion located on the medial side of the mandibular nerve.

• Postganglionic parasympathetic fibers leave the otic ganglion and join the auriculotemporal nerve, which carries them to the parotid gland.

• The maxillary artery is the largest branch of theexternal carotid artery in the neck.

• The maxillary artery originates within thesubstance of the parotid gland and then passesforward, behind the neck of mandible

• It passes through the infratemporal fossa to enterthe pterygopalatine fossa by passing through thepterygomaxillary fissure.

• This part of the vessel may pass either lateral ormedial to the lower head of lateral pterygoid.

Maxillary artery

• The first part of the maxillary artery (from the neck ofmandible to lateral pterygeoid muscle) gives:

• The middle meningeal artery

• inferior alveolar arteries

• Smaller branches: deep auricular, anterior tympanic, andaccessory meningeal.

• The second part of the maxillary artery (the part related tothe lateral pterygoid muscle) gives:

• Deep temporal, masseteric, buccal, and pterygoid branches.

• The third part of the maxillary artery is in thepterygopalatine fossa and gives:

• The posterior superior alveolar. Infra-orbital, Greaterpalatine, Pharyngeal and Sphenopalatine arteries and Theartery of the pterygoid canal.

Branches

• Middle meningeal artery

• Passes through the foramen spinosum to enter thecranial cavity.

• It passes between the two roots of theauriculotemporal nerve at their origin from themandibular nerve.

• Within the cranial cavity, it travel in the periosteal(outer) layer of dura mater, they can be damagedby lateral blows to the head.

• When the vessels are torn, result in an extraduralhematoma.

• Inferior alveolar artery

• It enter the mandibular foramen and canal.

• It is distributed to lower teeth, and the buccal gingivae,chin and lower lip.

• Before entering the mandible, it gives mylohyoid branchto mylohyoid.

Branches from the second part

• Deep temporal arteries, usually two in number,supply the temporalis muscle in the temporalfossa.

• Numerous pterygoid arteries supply the pterygoidmuscles.

• The masseteric artery, passes laterally throughthe mandibular notch to supply the massetermuscle.

• The buccal artery supplies skin, muscle, and oralmucosa of the cheek.

Third part of the maxillary artery

• It is the part of the maxillary artery in thepterygopalatine fossa

• Branches of the maxillary artery include;

• The posterior superior alveolar.

• Infra-orbital.

• Greater palatine.

• Pharyngeal.

• Sphenopalatine arteries.

• The artery of the pterygoid canal.

• The pterygoid plexus is a network of veins aroundlateral pterygoid muscle.

• Veins correspond to arteries branching from themaxillary artery in the infratemporal fossa andpterygopalatine fossa connect with the pterygoidplexus. These tributary veins include those thatdrain the nasal cavity, roof and lateral wall of theoral cavity, all teeth, muscles of the infratemporalfossa, paranasal sinuses, and nasopharynx.

Pterygoid plexus

• In addition, the inferior ophthalmic vein from the orbit drains through the inferior orbital fissure into the pterygoid plexus.

• Emissary veins connect the pterygoid plexus in the infratemporal fossa to the cavernous sinus through the foramen ovale.

• The pterygoid plexus connects anteriorly, via a deep facial vein, with the facial vein on the face.

The pterygopalatine fossa

• The pterygopalatine fossa is a small space behindand below the orbital cavity.

• It communicates:

• Laterally with the infratemporal fossa through thepterygomaxillary fissure,

• Medially with the nasal cavity through thesphenopalatine foramen,

• Superiorly with the skull through the foramenrotundum,

• Anteriorly with the orbit through the inferiororbital fissure

Boundaries of pterygopalatine fossa

• Anterior: superomedial part of the infratemporalsurface of maxilla

• Posterior: root of the pterygoid process andadjoining anterior surface of the greater wing ofsphenoid bone

• Medial: perpendicular plate of the palatine boneand its orbital and sphenoidal processes

• Lateral: pterygomaxillary fissure

• Inferior: part of the floor is formed by thepyramidal process of the palatine bone.

Contents

Contents of pterygopalatine fossa:

• 1. The pterygopalatine ganglion suspended bynerve roots from the maxillary nerve

• 2. The third part of the maxillary artery

• 3. The maxillary nerve (the second division of thetrigeminal nerve),

• 4. The nerve of the pterygoid canal, a combinationof the greater petrosal nerve (preganglionicparasympathetic) and the deep petrosal nerve(postganglionic sympathetic).

Pterygopalatine Ganglion

• The pterygopalatine ganglion is a parasympatheticganglion, which is suspended from the maxillarynerve in the pterygopalatine fossa. It issecretomotor to the lacrimal and nasal glands.

• Branches

• Orbital branches, which enter the orbit throughthe inferior orbital fissure

• Greater and lesser palatine nerves, which supplythe palate, the tonsil, and the nasal cavity

• Pharyngeal branch, which supplies the roof of thenasopharynx