Temporal and Infratemporal Fossae: Mastication and the Temporomandibular Joint

Overview

The temporal and infratemporal fossae together form the deep lateral compartment of the skull that houses the muscles of mastication, the mandibular division of the trigeminal nerve, the maxillary artery, and the temporomandibular joint (TMJ) — structures central to dental anesthesia, oral surgery, and TMJ disorders.

Temporal Fossa

• Bounded by the superior and inferior temporal lines superiorly, the zygomatic arch inferiorly, and floored by parts of the frontal, parietal, temporal, and greater wing of sphenoid (the pterion, a clinically important thin region, lies within this fossa).
• Occupied by the temporalis muscle, which converges through the zygomatic arch to insert on the coronoid process and anterior ramus of the mandible.

Infratemporal Fossa

An irregular space deep to the ramus of the mandible, continuous with the temporal fossa above.

Boundaries:

• Roof: infratemporal surface of the greater wing of sphenoid.
• Medial wall: lateral pterygoid plate.
• Lateral wall: ramus of the mandible.
• Anterior wall: posterior surface of the maxilla.

Contents:

• Lower part of temporalis, lateral and medial pterygoid muscles.
• Maxillary artery and its branches, including the inferior alveolar artery (accompanies the nerve of the same name into the mandibular canal) and middle meningeal artery (ascends through the foramen spinosum).
• Mandibular nerve (CN V3) and its branches: inferior alveolar, lingual, buccal, auriculotemporal.
• Otic ganglion, suspended from the mandibular nerve, relaying parasympathetic secretomotor fibers to the parotid gland.
• Chorda tympani, joining the lingual nerve to carry taste fibers (CN VII) and parasympathetic fibers to the submandibular and sublingual glands.
• Pterygoid venous plexus, an important route for spread of dental infection toward the cavernous sinus.

Muscles of Mastication

All four are innervated by the mandibular nerve (CN V3):

• Masseter: elevates the mandible (closes the jaw); superficial and deep heads span from the zygomatic arch to the ramus and angle.
• Temporalis: elevates and retracts the mandible; its posterior fibers are key for retrusion.