Infratemporal Fossa Anatomy

• The infratemporal fossa is a space beneath the base of the skull, located between the pharynx's side wall and the mandible's ramus.

Boundaries

• The medial boundary is the lateral surface of the lateral pterygoid plate.
• Behind it are the tensor and levator palati muscles and the superior constrictor.
• In front of the lateral pterygoid plate, lies the pterygomaxillary fissure which connects with the pterygopalatine fossa.
• The lateral wall consists of the ramus of the mandible and its coronoid process.
• The anterior wall is the posterior (infratemporal) surface of the maxilla, featuring small foramina for the posterior superior alveolar nerves and vessels.
• The inferior orbital fissure is a gap at the upper margin of the maxilla's wall between it and the sphenoid's greater wing.
• The roof is medially formed by the infratemporal surface of the sphenoid's greater wing and the adjacent squamous part of the temporal bone, in front of the articular tubercle.
• The infratemporal surface of the sphenoid is bounded laterally by the infratemporal crest.
• Lateral to the infratemporal crest, the roof is the space deep to the zygomatic arch, connecting the temporal and infratemporal fossae.
• The upper part of the carotid sheath forms the posterior boundary.

Contents

• The fossa includes the medial and lateral pterygoid muscles, separated by fat.
• It contains temporalis insertion into the coronoid process.
• The maxillary artery and branches, along with the pterygoid venous plexus, are inside the fossa.
• The mandibular nerve and its branches, the otic ganglion, and the chorda tympani are contents of the infratemporal fossa.
• Posterior superior alveolar branches of the maxillary nerve are also present.

Lateral Pterygoid

• Arises by two heads: the upper from the infratemporal surface of the skull and the lower from the lateral surface of the lateral pterygoid plate.
• The heads converge and fuse into a tendon inserted into the pterygoid fovea.
• The upper fibers of the tendon connect to the articular disc of the temporomandibular joint and the capsule's anterior part.
• Nerve supply is from a branch of the mandibular nerve's anterior division.
• Contraction draws the condyle and disc forward from the mandibular fossa down the articular tubercle's slope, essential for opening the mouth.

Medial Pterygoid

• Arises by two heads: a larger deep head from the medial surface of the lateral pterygoid plate and a smaller superficial head.
• The superficial head arises from the maxilla's tuberosity and the palatine bone's pyramidal process, merging with the main muscle mass.
• The muscle passes down and back at 45° to reach the angle of the mandible, inserting over the rough area as far as the groove for the mylohyoid vessels and nerve.
• Nerve supply is from a branch of the mandibular nerve's main trunk.
• Pulls the mandible upwards, forwards, and medially to close the mouth and move the mandible towards the opposite side.
• Important for chewing with molar teeth, especially in ruminants.
• Contracting with its opposite fellow and the two lateral pterygoids helps to protrude the mandible.

The infratemporal fossa is an anatomical space located beneath the skull's base, between the pharynx and mandible. It is defined by several boundaries including the pterygoid plate, mandible ramus, and maxilla. It contains important structures related to mastication and the passage of nerves and vessels.