CONTENTS

BOUNDARIES OF TEMPORAL & INFRATEMPORAL FOSSA

CONTENTS OF TEMPORAL AND INFRATEMPORAL FOSSA

APPLIED ANATOMY

SURGICAL APPROACHES

INTRODUCTION

• A knowledge of the anatomy of the infratemporal and Temporal fossae and their contents is essential for understanding the dental region.

• Many of the nerves and blood vessels supplying the structures of the mouth run through or close to these fossae.

• In addition, the infratemporal fossa contains the pterygoid muscles which play an important part in movements of the mandible.

ANTERIOR : ZYGOMATIC & FRONTAL BONE

POSTERIOR: INFERIOR TEMPORAL LINE & SUPRAMASTOID CREST

SUPERIOR: SUPERIOR TEMPORAL LINE

INFERIOR : ZYGOMATIC ARCH FLOOR : PARTS OF FRONTAL,

PARIETAL , TEMPORAL & GREATER WING OF SPENOID

TEMPORALIS MUSCLE IS ATTACHED TO THE FLOOR AND INFERIOR TEMPORAL LINE

TEMPORALIS MUSCLEMIDDLE TEMPORAL

ARTERYZYGOMATICOTEMPOR

AL NERVE & ARTERYDEEP TEMPORAL

NERVEDEEP TEMPORAL

ARTERY

TEMPORALIS MUSCLE• ORIGIN: floor of temporal fossa

& deep surface of temporal fasica

• INSERTION: the tendon passes deep to zygomatic arch to be inserted to all coronoid process NERVE SUPPLY: temporal branch from anterior division of mandibular nerve

• BLOOD SUPPLY:DEEP TEMPORAL ARTERY

• ACTION: Elevation of mandible, Its posterior fibers retract the mandible

Temporalis Muscle as a flap reconstruction This type of flap was first described

by Golovine in 1898. The approach to harvest is through a

temporal rhytidectomy incision and subperiosteal dissection.

Indicationsorbital reconstructionssling for the lower eyelid and lip in facial paralysisReconstruction of oral cavity and oropharynx defect

TRAUMA TO THE TEMPORAL REGIONThe bone of calvarium is thinnest in the temporal fossa. Strong blows to the side of the head may cause a depressed fracture, in which a fragment of bone is depressed inward to compress or injure the brain. At the pterion, the middle meningeal artery is easily ruptured following such an injury CAUSING EXTRA DURAL HEMATOMA. The resulting hematoma will compress the brain and could be fatal if untreated. TREATMENT• According to the "Guidelines for the Management of Traumatic Brain Injury, EDH with volume

greater than 30 mL should undergo surgical evacuation• This criterion becomes especially important when the EDH exhibits thickness of 15 mm or

more, and a midline shift beyond 5 mm

INFRATEMPORAL

FOSSA

Irregularly shaped space deep and inferior to the zygomatic arch, deep to the ramus of the mandible and posterior to the maxilla.

Communicates with the temporal fossa through the interval between (deep to) the zygomatic arch and (superficial to) the cranial bones.

Temporal fossa is superior to the zygomatic arch,

The infratemporal fossa is inferior to the zygomatic arch.

BOUNDARIES ANTERIOR : POSTERIOR

SURFACE OF BODY OF MAXILLA

ROOF : INFRATEMPORAL SURFACE OF GREATER WING OF SPHENOID

MEDIAL: LATERAL PTERYGOID PLATE AND PYRAMIDAL PROCESS OF PALATINE BONE

LATERAL: RAMUS OF MANDIBLE

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 and branches• The pterygoid venous plexus

THE PTERYGOID MUSCLES1. LATERAL PTERYGOID2. MEDIAL PTERYGOID

LATERAL PTERYGOID• ORIGIN:1. Upper head: infratemporal

surface of greater wing of sphenoid

2. Lower head: lateral surface of lateral pterygoid plate

• INSERTION: pterygoid fovea (in front of neck of mandible) + capsule & articular disc of TMJ

• NERVE SUPPLY: from anterior division of mandibular nerve

• ACTION:1. Pulls the condylar process

forward to depress the mandible 2. Side-to-side movement

RELATIONS OF LATERAL PTERYGOID

• Superficial: temporalis, masseter, ramus of mandible, maxillary artery, buccal nerve

• Deep: medial pterygoid, mandibular nerve, middle meningeal artery, otic ganglion

• Emerging through its upper border: deep temporal & masseteric nerves

• Emerging through its lower border: lingual & inferior alveolar nerves + maxillary artery

• Emerging between its 2 heads: buccal nerve, maxillary artery

MEDIAL PTERYGOID• ORIGIN:1. Superficial head: tuberosity of maxilla2. Deep head: medial surface of lateral pterygoid plate • INSERTION: medial surface of ramus & angle of mandible• NERVE SUPPLY: from trunk of mandibular nerve• ACTION: 1. Elevation of mandible2. Protrusion of mandible (when muscles on both sides act

together)3. Side-to-side movement (when muscles on both sides act

alternatively)

MASSETER

Neurovasculature of the infratemporal fossa• The maxillary artery is the larger of the two terminal branches of the

external carotid artery. • It arises posterior to the neck of the mandible and is divided into

three parts based on its relation to the lateral pterygoid muscle. 1st (mandibular) part: Deep to the condyle of mandible2nd (pterygoid) part: Neighbourhood of lateral pterygoid muscle3rd (pterygopalatine) part: into the pterygopalatine fossa

Branches of the 1st part:1) Deep auricular (to external acoustic meatus)2) Anterior tympanic artery (to the tympanic membrane)3) Middle meningeal (to dura mater and calvaria)4) Accessory meningeal aa. (to the cranial cavity)5) Inferior alveolar artery (to the mandibular gingiva and teeth)

Branches of the 2nd part:1) Deep temporal artery (to the temporal muscle)2) Pterygoid artery(to the pterygoid muscles)3) Masseteric artery (to the masseter muscle)4) Buccal artery (to the buccinator muscle)

o deep auricular (da)o anterior tympanic (at)o middle meningeal (mm)o accessory middle meningeal (amm)o inferior alveolar (ia)o buccal (b)o deep temporal (dt)o posterior superior alveolar (psa)o descending palatine (dp)o infraorbital (io)o sphenopalatine (sp)

PTERYGOID VENOUS PLEXUS

• This is situated around, and within, the lateral pterygoid muscle and it surrounds the maxillary artery.

• Its tributaries correspond to the various branches of the maxillary artery

• The plexus communicates with the cavernous sinus, the facial vein, the inferior ophthalmic vein and the pharyngeal plexus.

• The pterygoid venous plexus chiefly drains posteriorly into the maxillary vein.

Clinical notes of venous drainage:

•Anastomoses of the pterygoid venous plexus with the facial vein and cavernous sinus represent an important potential pathway for the spread of infection.

•Normally, blood from the medial angle of the eye, nose and lips drains down through the facial vein.

• Veins in the head, including those of the pterygoid venous plexus, do not have valves, however.

• Infections may therefore reverse the flow of blood into the cavernous sinus, resulting ultimately in meningeal infections.

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.

Branches within the infratemporal fossa is divided into three groups:1) Branches arising from the trunk

Spinous nerveMedial pterygoid nerve

2) Anterior branchesBuccal nerveMasseteric nerveDeep temporal nervesLateral pterygoid nerve

3) 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.

Masseteric nerve, deep temporal nerves, lateral pterygoid nerve innervate the muscles with the same name.

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.

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

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.

CLINICAL CORRELATION OF INFRATEMPORAL FOSSA AND MANDIBULAR NERVE BLOCK

The pathways are significant clinically because they help describe the consequences of interrupted nerve function, due either to anesthesia or injury. To numb the mandibular teeth for a dental procedure, anesthetic is injected at the lingula of the mandible to block the inferior alveolar nerve. If the needle passes too far posteriorly, it may anesthetize branches of CN VII coursing through the parotid gland.

CLINICAL CORRELATON-AURICULOTEMPORAL Nerve

• Frey’s syndrome produces flushing and sweating instead of salivation in response to taste of food after injury of the auriculotemporal nerve, which carries parasympathetic secretomotor fibers to the parotid gland and sympathetic fibers to the sweat glands.

• When the nerve is damaged, the fibers can regenerate along each other’s pathways and innervate the wrong gland.

• It can occur after parotid surgery and may be treated by cutting the tympanic plexus in the middle ear.

INFRATEMPORAL FOSSA AND NERVE BLOCKS FOR THE MAXILLA

• The posterior superior alveolar artery runs with the nerve(s), but is no more likely to be damaged than arteries in other neurovascular bundles.

• The pterygoid venous plexus lies within and around the lateral pterygoid muscle, and should not be damaged unless the needle is inserted too deeply or laterally.

• If a positive (venous) aspiration is observed during this procedure, withdrawal will disengage the needle with minimal bleeding resulting—injecting into the friable plexus causes disruption which can lead to haematoma formation and postoperative trismus.

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.

APPROACHES TO INFRATEMPORAL FOSSA

Several surgical approaches to the infratemporal fossa have been described over the years and some of them have been improved and modified. Basically the various approaches can be grouped under the following categories, which are

Transoral, Transantral, Transpalatal, Transmaxillary, Extended maxillotomy, Maxillary swing, Transmandibular, Transzygomatic , Facial translocation, Transcranial, Combined

TRANSORAL APPROACH

• The superior gingivolabial sulcus posteriorly is close to the tuberosity of the maxilla and provides access to the lower part of the infratemporal fossa.

• An approach through this area does not provide enough exposure for removal of tumours,

• the view is obstructed by fatty tissue and there is no vascular control.

• However, the recess provides access for biopsy purposes especially if the lesion is located low in the infratemporal fossa.

• Occasionally a benign tumour may be removed through this approach.

TRANSANTRAL APPROACH• The antral cavity is entered through a sublabial incision, extending from the level of the canine to the first molar tooth and the mucoperiosteal flap is elevated until the infraorbital foramen, so as to preserve the infraorbital vessels and

• A window is made into the anterolateral wall of the antrum large enough to provide good exposure of the complete posterior wall of the maxillary sinus.

• The roots of the canine and premolars are preserved. • The antral mucosa on the posterior wall is incised at its

junction with the medial, lateral and superior walls, and the mucoperiosteal flap is reflected down.

• The periosteum on the outer surface of the posterior wall is incised along its medial, lateral and superior border and reflected downwards.

• At the end of the procedure the bony posterior wall and the mucoperiosteal flap are replaced.

• This approach is not suitable for tumour excision by itself, but may be combined with other approaches. It is invariably employed for the purpose of obtaining a biopsy.

TRANSPALATAL APPROACH• The authors Kornfehl et al. have basically described a transpharyngeal

approach via the palate. • The nasopharynx is reached via an ‘S'-shaped incision running

vertically on the soft palate and on to the anterior pharyngeal arch towards the side of the lesion.

• The mucosa of the lateral wall of the nasopharynx is incised vertically, the superior constrictor muscle of the pharynx is split to enter the most medial part of the infratemporal fossa.

• Kornfehl et al. employed this approach to extirpate a cavernous haemangioma close to the lateral pterygoid muscle which had been shown not to have any feeding vessels.

• This is not a safe approach for tumour excision. • The internal carotid artery is close to the pharyngeal wall and it is not

possible to obtain any control on the vessel. The exposure obtained is limited.

TRANSMAXILLARY APPROACH• It was originally described by

Langenbeek in 1859 as an osteoplastic technique for tumours of the pterygopalatine fossa.

• An incision is placed in the buccal sulcus above the attached gingivae between the maxillary second premolars.

• the incision is placed half a centimetre above the apices of tooth to ensure the viability of the teeth.

• A mucoperiosteal flap is raised. The nasal septum is separated from the anterior nasal spine and the maxillary crest and the facial soft tissue are retracted cranially.

• An osteotomy incision is placed, using an electric burr from one maxillary tuberosity to the other.

• The incision passes just under the zygomatic buttress and divides the anterior nasal aperture.

• An osteotomy of the medial wall of the maxilla is performed through the inferior meatus to the palatine canal. At this stage the palate and the inferior portion of the maxilla remain attached by the pterygomaxillary suture, the thin posterior wall of the maxillary sinus and the bone forming the canal of the palatine vessels.

• Using a curved osteotome the maxilla is separated and disimpacted downwards.

• The buttress of bone anterolaterally and at the piriform nasal aperture are preserved so that they can be approximated at closure.

EXTENDED MAXILLOTOMY APPROACH• This is essentially a transantral approach

with an extended sublabial incision taken from the midline to the maxillary tuberosity and carried down to the periosteum.

• The posterior wall of the maxillary sinus is widely excised allowing access to the pterygomaxillary portion of the tumour.

• The medial wall of the maxillary sinus and the nasopharynx is removed. Lateral extension of the tumour can be exposed by removing the lateral wall of the antrum.

• It can also be combined with a transpalatal approach. It was described by Krause and Baker who used it mainly for surgical treatment of nasopharyngeal angiofibroma.

TRANSMANDIBULAR APPROACH• The concept of approaching the retromaxillary area through

a mandibulotomy is not new and has been advocated by Conley and Barbosa. The infratemporal fossa communicates inferiorly with the neck.

• If the mandible is laterally retracted and the medial pterygoid muscle is detached from its mandibular attachment the infratemporal space can be reached.

• This approach provides good control of the vessels and nerves and en bloc resection of nasopharynx, posterior maxilla, infratemporal fossa structures, mandibular ramus and parotid gland can be performed.

• The procedure has been modified by Attia et al. to obtain wide field exposure without sacrifice of either mandibular function or the sensory supply of the face and oral cavity.

• The mandibular osteotomies are arranged to spare the inferior alveolar nerve and vessels and are positioned under the intercondylar notch above the opening of the mandibular canal and just medial to the mental foramen.

• Detachment of the medial and lateral pterygoid muscles and the sphenomandibular ligament allows the mandibular segment to be reflected superiorly .

• This provides direct access to the infratemporal fossa; osteosynthesis of the mandible and intermaxillary fixation is performed. The procedure preserves function, exposure is good and is cosmetically acceptable.

MAXILLARY SWING• Incision – Weber Ferguson incision

without gingivolabial component• Bilateral tarsorraphy should be performed• Inverted “U” shaped incision is marked

out on the hard palate• After deepening the facial incision the

lacrimal sac should be skeletonized and sectioned at its lower end.

• Infra orbital nerve should be sectioned as it comes out of infraorbital foramen.

• Periosteum of the inferior orbital wall should be elevated.

• Osteotomies should be performed on the frontal process of maxilla and at the maxillo zygomatic suture.

• The maxillo ethmoidal junction should be separated using a straight osteotome.

• The mucoperiosteum over the hard palate should be elevated based on the contralateral greater palatine vessels. The ipsilateral greater palatine vessels were cauterized and sectioned.

• A straight osteotome should be placed between the arms of a v shaped notch located on the anterior nasal spine and hammered in order to separate the maxilla down the middle.

• Now the whole maxilla with its attached cheek tissue can be swung like a door laterally exposing the whole of nasopharynx.

• Mass in the naso pharynx can now be removed under direct vision.

• Maxilla can be repositioned after surgery and secured in position by using miniplate and screws.

COMBINATION OF APPROACHES

• Radical excision of tumours and the relatively limited access obtained by any single approach have made combined approaches necessary.

• It offers the patients the maximum benefit of the technical ‘know-how’ of the surgical team and the best opportunity for surgical excision.

- HOLLINSHED- BOOK OF ANATOMY- GRAYS ANATOMY- LAST ANATOMY- ATLAS OF HUMAN BODY- NETTERS- B.D.CHAURASIA- TEXT BOOK OF

ANATOMY- JOHN D LANGDON- SURGICAL ANATOMY

OF INFRATEMPORAL FOSSA- JATIN SHAH- HEAD AND NECK CANCER

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Surgical and applied anatomy of tongue and soft palate

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DR.CHINTAN