infratemporal fossa is a irregular space with numerous neurovascular structures. an attempt has been made by me to decode all the boundaries and structures in a systematic way. sincere thanks to Dr. Viren Karia for his awesome video.
• The infratemporal fossa is a complex and irregularly
shaped space, located deep to the masseter muscle.
• It acts as a conduit for many neurovascular structures
that travel between the cranial cavity and other
structures of the head.
• A precise knowledge of the structures and boundaries
help to reduce intra operative complications
• Anterior: the posterior surface of the maxilla
• Posterior: the styloid process, carotid sheath and
deep part of the parotid gland.
• Medial: lateral pterygoid plate
• Lateral: the ramus and coronoid process of the
the infratemporal surface of the greater wing of the
The infratemporal fossa has NO anatomical floor,
being continuous with tissue spaces in the neck.
The infratemporal fossa communicates with the
temporal fossa deep to the zygomatic arch
1. Lateral and medial pterygoid muscles.
2. Infratemporal pad of fat
3. Buccal lymph node
4. Mandibular nerve
5. Chorda tympani nerve
6. Maxillary artery
7. Pterygoid plexus of veins
8. Otic ganglion
9. Sphenomandibular ligament
Lateral pterygoid muscle
• largest component of the infratemporal fossa.
• This muscle has two heads, upper and lower.
• The upper head is smaller and arises from the
greater wing of sphenoid,
• while the larger lower head arises from the lateral
aspect of lateral pterygoid plate.
• The fibers of both these heads pass backwards to
be inserted into the neck of the mandible.
• The action of lateral pterygoid muscle i.e.
protrusion of the lower jaw can easily be tested
during clinical examination of the patient.
Medial pterygoid muscle
• This muscle is the deepest of the four muscles of
• It consists of two heads.
• The bulk of the muscle arises as a deep head from
the medial surface of the lateral pterygoid plate.
• Thus, the lateral pterygoid plate of the sphenoid
bone gives rise to both pterygoid muscles
• The smaller, superficial head of the medial pterygoid
muscle originates from
• the maxillary tuberosity and
• the neighbouring part of the palatine bone
• the fibres pass downwards and backwards to insert into
the roughened surface of the angle of the mandible on
its medial aspect.
• The medial pterygoid muscle is an elevator of the
• It assists in lateral and protrusive movements.
• The medial pterygoid muscle is synergistic to the
2. Infratemporal pad of fat:
• Lies between the temporalis muscle and the
infratemporal surface of maxilla.
• The pad of fat helps in outlining the posterior
antral tumor spread in CT scans.
• This infratemporal pad of fat continues with the
cheek pad of fat passing between the posterior wall
of maxilla and the zygoma.
• A mass present behind the maxilla always betrays
itself by displacing this pad of fat and causing a
puffy sweeling of the cheek (angiofibroma)
3. Buccal lymph node:
• Within this infratemporal pad of fat lies the buccal
• This node links the infratemporal lymphatics to the
• Lymphatic drainage of the infratemporal fossa
region is into the submandibular and upper deep
cervical group of nodes
• enlargement of the nodes in this region should
alert the clinician to the possibility of infection
arising in the infratemporal fossa.
• This node should never be left behind during
surgical resection of infratemporal fossa for
malignant tumors as it could commonly cause local
4. Mandibular nerve
• penetrates the roof of the infratemporal fossa
through the foramen ovale.
• It gives rise to inferior alveolar and lingual nerve
Buccal branch of mandibular nerve
• Using the medial and lateral pterygoid muscles as
• the buccal branch of the mandibular nerve
accompanying buccal artery
• The nerve and artery usually pass between the two
heads of the lateral pterygoid muscle.
• the lingual nerve
• inferior alveolar nerve
• These two nerves pass between the medial and
lateral pterygoid muscles.
Course of these nerves
• Distally, the inferior alveolar nerve enters the
• The lingual nerve lies superior to the inferior
alveolar nerve and passes anteriorly to reach the
• the inferior alveolar nerve, artery, and vein emerge
from the mental foramen as
• the mental nerve,
• mental artery,
• And mental vein .
Auriculo temporal nerve
• the auriculotemporal nerve has two roots that
encircle the middle meningeal artery.
• It carries sensory fibers from the skin of the
• and postganglionic parasympathetic fibers from
the otic ganglion to the parotid gland.
5. Chorda tympani
• chorda tympani nerve emerges from the
• passes anteriorly to join the lingual nerve
• This nerve carries special sensory taste fibers from
the anterior two-thirds of the tongue and
• preganglionic parasympathetic fibers to the
• maxillary artery and its branches lies on the
superficial or deep surface of the lateral pterygoid
6. Pterygoid venous plexus
• venous plexus of considerable size,
• situated between the temporalis muscle and lateral
• partly between the two pterygoid muscle
• These plexus could cause troublesome bleeding during
total maxillectomy surgery.
Veins contributing for plexus
• middle meningeal
• deep temporal (anterior & posterior)
• some palatine veins (palatine vein which divides into the
greater and lesser palatine v.)
• a branch which communicates with the ophthalmic vein
through the inferior orbital fissure
• infraorbital vein
• The pterygoid venous plexus communicates with the
cavernous sinus via two routes.
• One is via emissary veins passing through the
foramen ovale, foramen spinosum.
• Another route is via the deep facial vein, which links
the pterygoid venous plexus with the facial vein.
• The facial vein connects with the superior ophthalmic
vein, which drains into the cavernous sinus.
• Due to its communication with the cavernous
sinus, infection of the superficial face may spread
to the cavernous sinus, causing cavernous sinus
Cavernous sinus thrombosis
• Complications may
• edema of the eyelids,
conjunctivae of the
• paralysis of cranial
nerves which course
through the cavernous
7. Otic ganglion
• located inferiorly to the foramen ovale,
• medial to the mandibular nerve
• preganglionic fibres from inferior salivatory nucleus
(associated with the glossopharyngeal nerve).
• Parasympathetic fibres travel within a branch of the
glossopharyngeal nerve, the lesser petrosal nerve, to
reach the otic ganglion.
• Post ganglionic fibres along the auriculotemporal nerve
(branch of the mandibular division of the trigeminal
• provide secretomotor innervation to the parotid gland.
• Sympathetic fibres from the superior cervical chain
pass through the otic ganglion.
• They travel with the middle meningeal artery to
innervate the parotid gland.
7. Sphenomandibular ligament
• a flat, thin band which is attached superiorly to the
spine of the sphenoid bone, and, becoming
broader as it descends,
• It is fixed to the lingula of the mandibular foramen.
• it limits distension of the mandible in an inferior
• It is slack when the TMJ is in closed position.
• It is taut as the condyle of the mandible is in front
of the temporomandibular ligament.
• The infratemporal fossa communicates
superiorly with middle cranial fossa by the
neurovascular formina like
• carotid canal,
• jugular foramen,
• foramen spinosum,
• foramen ovale
• foramen lacerum.
• Medially the infratemporal fossa communicates
with pterygopalatine fossa through the
• With orbit through infra orbital fissure
• The pterygomaxillary fissure is contiguous with that
of the infraorbital fissure.
• The roof of the infratemporal fossa is open to the
temporal fossa lateral to the greater wing of
sphenoid, deep to the zygomatic arch.
• Benign tumors involving the infratemporal fossa
always respect these boundaries
• They expand in the direction of soft tissue planes,
or follow preexistant pathways and foramen
• Maxillofacial trauma , maxillary osteotomies, have
the potential to disrupt the soft tissue contents of
the infratemporal fossa
• These fractures frequently extend to involve the
bones immediately adjacent to them
• Infection of the infratemporal fossa is most
commonly associated with a pericoronitis of
mandibular third molar tooth
• dental abscess of this tooth, or as a result of
infection following tooth extraction
• Rarely, it may result from an infected needle used
during an inferior alveolar nerve block.
• Infection of the infratemporal region may be
secondary due to spread from an adjacent infected
• The main symptom is trismus (though a common
symptom of parapharyngeal abscess)generally
affecting the medial pterygoid muscle
• Externally there is usually little evidence of tissue
• Spread of infection from the infratemporal fossa
region to involve the buccal space is characterised
by the presence of a swelling of the cheek
• The swelling is bounded above by the zygomatic
arch and below by the lower border of the
mandible, both landmarks being palpable.
• Infection from the infratemporal fossa may spread
• directly around the back of the maxillary tuberosity
• into the orbit via the inferior orbital fissure.
• This may result in cavernous sinus thrombosis
• Once in the orbit, further direct spread of infection
through the superior orbital fissure will gain
entrance into the cranial cavity.
• Spread from the infratemporal fossa via the
pterygomaxillary fissure may also involve the
• which contains the maxillary nerve,
• maxillary artery
• pterygopalatine ganglion
• From the pterygopalatine fossa a number of small
canals lead into
Take home message
• Numerous structures in this deep irregular space expects us
to be anatomically oriented
• Potential communication to cavernous sinus, middle cranial
fossa and orbit makes this area a potential high risk space
• Highly vascular area due to pterygoid plexus and maxillary
artery warns surgeons to be alert to prevent bleeding
• Appearance of infections in other tissue spaces like orbit,
pterygopalatine fossa, and in the maxillary antrum should
prompt a primary site in infratemporal fossa