What are the boundaries of the infratemporal fossa?
The infratemporal fossa is an irregular anatomical space defined by the following osseous and soft-tissue boundaries:
- Superior boundary — The infratemporal surface of the greater wing of the sphenoid bone, along with the zygomatic arch and the infratemporal crest (crista infratemporalis), which separates it from the temporal fossa above.
- Anterior boundary — The maxilla (specifically the maxillary tuberosity and infratemporal surface).
- Inferior boundary — The buccopharyngeal fascia.
- Posterior boundary — The styloid process of the temporal bone and its associated muscles.
- Medial boundary — The lateral pterygoid plate of the sphenoid bone.
- Lateral boundary — The medial surface of the ramus of the mandible.
What are the communications of the infratemporal fossa?
The infratemporal fossa communicates with adjacent regions through several openings:
- External skull base (Basis cranii externa) — The external skull base transitions freely and laterally into the infratemporal fossa.
- Orbit — Via the inferior orbital fissure.
- Oral cavity — Via alveolar canals.
- Pterygopalatine fossa (Fossa pterygopalatina) — Via the pterygomaxillary fissure. The pterygopalatine fossa lies medial to the infratemporal fossa as a slit-like continuation.
- Mandible — Via the mandibular canal.
- Temporal region — The fascial and fat spaces of the temporal region communicate directly with the infratemporal fossa.
What are the contents of the infratemporal fossa?
The primary muscular structure associated with this region is the lateral pterygoid muscle (m. pterygoideus lateralis). It originates from the roof of the infratemporal fossa and the lateral pterygoid plate, inserting onto the capsule and articular disc of the temporomandibular joint (TMJ) as well as the neck of the mandibular condyle. It acts to protrude the mandible and perform lateral excursion (diduction).
Clinical Significance in Surgery and Trauma
- Penetrating and Non-Penetrating Wounds: In severe facial trauma (frequently shrapnel injuries, less commonly gunshot wounds), projectiles may penetrate deep into the facial tissues. The infratemporal fossa is a common site for retained foreign bodies in such trauma.
- Odontogenic Infections: The infratemporal fossa is one of the most critical locations for deep fascial abscesses and phlegmons originating from the maxillary dentition. Infections here tend to be highly aggressive. The primary danger lies in the high risk of the purulent process spreading directly into the cranial cavity.
- Routes of Infection: Infection can spread into the infratemporal fossa from adjacent fascial spaces, including the deep temporal space located between the temporalis muscle and the temporal bone.
- Topographic Classification: Unlike the pterygomandibular, parapharyngeal, and retromandibular spaces, the infratemporal fossa is not classified among the fascial spaces immediately surrounding the mandible.