The infratemporal fossa is an irregularly shaped cavity that is a part of the skull. It is situated below and medial to the zygomatic arch. It is not fully enclosed by bone in all directions. It contains superficial muscles, including the lower part of the temporalis muscle, the lateral pterygoid muscle, and the medial pterygoid muscle. It also contains important blood vessels such as the middle meningeal artery, the pterygoid plexus, and the retromandibular vein, and nerves such as the mandibular nerve (CN V₃) and its branches.

The boundaries of the infratemporal fossa occur:

The infratemporal fossa contains the maxillary artery (originating from the external carotid artery). It also contains some of its branches, including the:

The infratemporal fossa contains the pterygoid plexus, and the retromandibular vein.

The infratemporal fossa contains the mandibular nerve, the inferior alveolar nerve, the lingual nerve, the buccal nerve, the chorda tympani nerve, and the otic ganglion.

The mandibular nerve, the third branch of the trigeminal nerve (CN V₃), also known as the "inferior maxillary nerve", enters infratemporal fossa from the middle cranial fossa through the foramen ovale of the sphenoid bone.

The mandibular nerve gives off four nerves to the four muscles of mastication in the infratemporal fossa. These are the masseteric nerve to masseter muscle, the deep temporal nerve to temporalis muscle, the lateral pterygoid nerve to lateral pterygoid muscle, and the medial pterygoid nerve to medial pterygoid muscle. It also gives branches to mylohyoid muscle, the anterior belly of digastric muscle, the tensor veli palatini muscle, and tensor tympani muscle.

The mandibular nerve also gives off many sensory branches, including: