The infratemporal fossa (latin: fossa infratemporalis) is an irregularly shaped space on the side of the skull below the zygomatic arch and deep to the ramus of the mandible. The infratemporal fossa is located below the temporal fossa and is continuous with it.
The borders or walls of the infratemporal fossa are formed by bone and soft tissue, and they are as following:
- superior (roof): greater wing of the sphenoid;
- inferior (floor): medial pterygoid muscle;
- lateral: medial surface of ramus of the mandible;
- medial: lateral pterygoid plate of the sphenoid bone;
- posterior: carotid sheath.
The infratemporal fossa serves as a passageway for neurovascular structures that travel between the cranial cavity, the temporal fossa and the pterygopalatine fossa. It also contains several muscles of mastication.
The structures passing the infratemporal fossa are as following:
- nerves and ganglia: mandibular nerve and its major branches - auriculotemporal, buccal, lingual, and inferior alveolar nerves, chorda tympani - branch of the facial nerve, lesser petrosal nerve, and otic ganglion;
- blood vessels: maxillary artery and pterygoid venous plexus;
- muscles: medial and lateral pterygoid muscles, tendon of temporal muscle.
There are several openings in the walls of the infratemporal fossa that connect it with different cavities and fossae of the skull to transmit nerves and blood vessels. These are the following:
- foramen spinosum,
- foramen ovale,
- petrotympanic fissure,
- pterygomaxillary fissure.
The foramen spinosum connects the infratemporal fossa with the middle cranial fossa of the internal cranial base and transmits the meningeal branch of the mandibular nerve, as well as the middle meningeal artery and vein.
The foramen ovale also connects the infratemporal fossa with the middle cranial fossa to transmit the mandibular division of the trigeminal nerve, the lesser petrosal nerve, the accessory meningeal branch of the maxillary artery, and an emissary vein.
The petrotympanic fissure is located on the temporal bone and serves as a passage for the chorda tympani (a branch of the facial nerve) between the tympanic cavity and the infratemporal fossa.
The pterygomaxillary fissure connects the infratemporal fossa with the pterygopalatine fossa and transmits the terminal part of the maxillary artery, as well as the superior alveolar nerve, which is a branch of the maxillary nerve.