ANATOMY OF PTERYGOPALATINE FOSSA AND INFRATEMPORAL SPACE

PRESENTER : DR SHWETA SHARMAMODERATOR : DR A. K. SHARMA

DR. ANIRUDDHA SARKAR

• Review of osteology

• Infratemporal space

• Pterygopalatine fossa

• Radiology

Review of osteology

Infratemporal space

– Boundaries

– Contents

Irregularly shaped space

boundaries Superiorly: the inferior (infratemporal) surface of the greater wing of the sphenoidInferiorly: where the medial pterygoid muscle attaches to the mandible near its angle

Laterally: ramus of the mandible Medially: lateral pterygoid plateAnteriorly: posterior aspect of the maxillaPosteriorly: tympanic plate ,mastoid and styloid processes of the temporal bone, anterior aspect of parotid gland

Contents

1. Inferior part of the temporalis muscle2. Lateral and medial pterygoid muscles3. Maxillary artery4. Pterygoid venous plexus5. Mandibular, inferior alveolar, lingual, buccal, chorda tympani nerves6. Otic ganglion

muscles

MAXILLARY ARTERY

Pterygoid venous plexus Lies around and within the lateral pterygoid muscles.

• Tributaries:Correspond to the branches of the maxillary artery

• Communications

Mandibular nerve Arises from the trigeminal ganglion in the middle cranial fossa. Immediately receives the motor root of the trigeminal nerve Leaves the cranium through the foramen ovale into the infratemporal

fossa.

Mandibular nerve

Branches within the infratemporal fossa is divided into three groups:

1) Branches arising from the trunkSpinous nerveMedial pterygoid nerve 2) Anterior branchesBuccal nerveMasseteric nerveDeep temporal nervesLateral pterygoid nerve3) Posterior branchesAuriculotemporal nerveLingual nerve Inferior alveolar nerve

The spinous nerve passes through the spinous foramen and enters the cranium. It is a sensory nerve innervating the dura mater.

The medial pterygoid nerve innervates the medial pterygoid muscle, tensor veli palatini muscle and the tensor tympani muscle.

Buccal nerve, masseteric nerve, deep temporal nerves, lateral pterygoid nerve innervate the muscles with the same name except the buccal nerve.

Buccal nerve is sensory and innervates the inner surface of the cheek.

Auriculotemporal nerve Supplies sensory fibers to the auricle and temporal region. Also sends articular (sensory) fibers to the TMJ. Conveys postsynaptic parasympathetic secretomotor fibers from

the otic ganglion to the parotid gland.

The inferior alveolar nerve 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.

The terminal branch of the inferior alveolar nerve is the mental nerve which passes through the mental foramen.

Chorda tympani nerve A branch of CN VII carrying taste fibers from the anterior two thirds

of the tongue.

Joins the lingual nerve in the infratemporal fossa.

Also carries secretomotor fibers for the submandibular & sublingual salivary glands.

Lingual nerve sensory to the anterior two thirds of the tongue, the floor of the mouth, and the lingual gingivae.

Otic ganglion (parasympathetic)

Located in the infratemporal fossa, just inferior to the foramen ovale. Presynaptic parasympathetic fibers, derived mainly from the glossopharyngeal nerve (via the lesser petrosal nerve), synapse in the otic ganglion.

Postsynaptic parasympathetic fibers, secretory to the parotid gland, pass from the otic ganglion to this gland through the auriculotemporal nerve.

Sympatheic root is derived frm the plexus on middle mennigeal artery ( it contains post ganglioninc fibres arising in the superior cervical ganglion; without relaying in otic reach parotid via auriculotemporal nerve)

glossopharyngeal nerve (via the lesser petrosal nerve)

Pterygopalatine fossa

– Boundaries– Contents

Pterygopalatine Fossa A small space behind and below the orbital cavity.

An inverted 'tear-drop' shaped space between bones on the lateral side of the skull immediately posterior to the maxilla.

Pterygomaxillary fissure

Infra orbital fissure

Posterior surface of maxilla

Behind : root of pterygoid process & adjoining anterior surface of greater wing of spenoid

Medially : palatine bone’s prependicular plate with its orbital & sphenoidal process

Anteriorly : suoero medial part of maxilla’s posterior surface

Laterally : connects with infratemporal fossa via pterygomaxillary fissure

The part of the sphenoid bone that contributes to the formation of the pterygopalatine fossa is the anterosuperior surface of the pterygoid process. Opening onto this surface are two large foramina: • maxillary nerve [V2] through foramen rotundum middle cranial fossa• greater petrosal nerve from the facial nerve [VII] + sympathetic fibers internal carotid plexus join to form the nerve of the pterygoid canal that passes into the pterygopalatine fossa through the anterior opening of the pterygoid canal.

The pterygoid canal is a bony canal opening onto the posterior surface of the pterygoid process.

The pterygoid canal opens into the middle cranial fossa just anteroinferior to the internal carotid artery as the vessel enters the cranial cavity through the carotid canal.

Although small in size, the pterygopalatine fossa communicates via fissures and foramina in its walls with: 1) the middle cranial fossa 2) infratemporal fossa 3) floor of the orbit 4) lateral wall of the nasal cavity 5) oropharynx 6) roof of the oral cavity

Gateways

7 foramina and fissures provide apertures through which structures enter and leave the pterygopalatine fossa:

foramen rotundum & pterygoid canal middle cranial fossa palatovaginal canal nasopharynx palatine canal leads oral cavity (hard palate) sphenopalatine foramen nasal cavity pterygomaxillary fissure infratemporal fossa inferior orbital fissure orbit

The contents of the pterygopalatine fossa1) Third part (pterygopalatine part) of the maxillary artery2) Maxillary nerve3) Nerve of the pterygoid canal (Vidian’s nerve)4) Pterygopalatine ganglion

All the upper teeth receive their innervation and blood supply from the maxillary nerve [V2] and the terminal part of the maxillary artery, respectively, that pass through the pterygopalatine fossa.

Maxillary Nerve (V2)

Purely sensory

Originates from the trigeminal ganglion in the cranial cavity

Exits the middle cranial fossa

Enters the pterygopalatine fossa (foramen rotundum)

Exits as the infra-orbital nerve (inferior orbital fissure)

Gives sensory fibers to the skin of the face and the side of the nose.

Maxillary Nerve (V2)

Within the fossa, the maxillary nerve is attached to the pterygopalatine ganglion by two ganglionic branches.

Sensory fibers from the nose, the palate, and the pharynx. Postganglionic parasympathetic fibers to the lacrimal gland.

Branches

More anteriorly posterior superior alveolar nerves are given off.

Pass through the pterygopalatine maxillary fissure into the infratemporal fossa.

Here they divide into numerous small branches • Enter the maxilla through the posterior alveolar foramina Supply the upper molar teeth, the mucous membrane on the buccal surface of the associated alveolar process and the lining of the maxillary sinus.

Anesthesia of the upper molar teeth and associated buccal mucosa can be achieved by a posterior superior alveolar block.

As the maxillary nerve is about to enter the inferior orbital fissure it gives rise to the zygomatic nerve. divides into:

Zygomaticotemporal branch passing into temporal fossa to supply skin of the temple Zygomaticofacial nerve supplies skin over the prominence of cheek.

Pterygopalatine Ganglion(Ganglion pterygopalatinum, Meckel's ganglion, Nasal ganglion, Sphenopalatine ganglion)

Largest of the 4 parasympathetic ganglia in the head Formed by the cell bodies of the postganglionic neurons associated

with preganglionic parasympathetic fibers of the facial nerve [VII] carried by the greater petrosal nerve and the nerve of the pterygoid canal.

Branches

• Orbital branches, enter the orbit (inferior orbital fissure) Supply of the orbital wall and of the sphenoidal and ethmoidal sinuses.

• Greater and lesser palatine nerves, supply the palate, the tonsil, and the nasal cavity.

• The greater palatine nerve originates from the geniculate ganglion of the facial nerve [VII] in the temporal bone.

• In the palatine canal, gives origin to posterior inferior nasal nerves, which contribute to the innervation of the lateral nasal wall.

• Greater petrosal nerve enters the pterygoid canal and becomes the nerve of the pterygoid canal

• Pharyngeal branch, which supplies the roof of the nasopharynx

1. infraorbital nerve 2. posterior superior alveolar nerve 3. pterygopalatine ganglion (parasympathetic) 4. greater palatine nerve 5. lesser palatine nerve cut 6. nasopalatine nerve 7. nerve of the pharyngeal canal

CONCLUSSION

Maxillary ArteryA major branch of the external carotid artery in the neck. Passes through the infratemporal fossaEnters the pterygopalatine fossa through the pterygomaxillary fissure.

Branches of the third part of the maxillary artery

1)Posterior superior alveolar artery2)Infra-orbital artery3)Greater palatine artery4)Pharyngeal artery5)Sphenopalatine arteries6)Artery of the pterygoid canal

Collectively, these branches supply much of the nasal cavity, the roof of the oral cavity, and all upper teeth. In addition, they contribute to the blood supply of the sinuses, oropharynx, and floor of the orbit.

The maxillary artery gives off the posterior superior alveolar branch as it enters the pterygopalatine fossa.

Runs with the corresponding branches of the maxillary nerve to suppy the upper posterior teeth and adjacent structures.

Veins

The veins pass through the pterygomaxillary fissure to join the pterygoid plexus of veins in the infratemporal fossa.

Innervation of the lacrimal glandThe parasympathetic secretomotor nerve supply is derived from the lacrimal nucleus of the facial nerve. The preganglionic fibers reach the pterygopalatine ganglion via the nervus intermedius and its great petrosal branch.

Radiology Axial CT bone window of skull base from inferior to superior aspect showing

major apertures of skull base

Axial CT bone window of skull base from inferior to superior aspect showing major apertures of skull base

Axial CT bone window of skull base from inferior to superior aspect showing major apertures of skull base

Coronal CT bone window of central skull base

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