This oval shaped fossa is bounded superiorly and posteriorly by the temporal lines. The frontal and zygomatic bones form the anterior boundary. Laterally, the fossa is covered by the temporal fascia. Inferiorly the floor is formed by portions of the sphenoid, frontal, temporal and parietal bones. The area where these four bones meet is the pterion. This is also the area where the temporalis muscle originates. Temporal muscle divides into a superficial and deep layer. The superficial layer attaches to the superior aspect of zygomatic arch. The deep layer extends inferiorly to become the masseter muscle.
Infratemporal Fossa
This space is bounded superiorly by the greater wing of the sphenoid and anteriorly by the infratemporal surface of the maxillary bone. The posterior wall is formed by the condyle of the mandible and the styloid process of the temporal bone. The lateral wall is the medial aspect of the ramus of the mandible. The medial wall is lateral pterygoid plate.
The Maxillary Artery originates from the external carotid and enters medially to the ramus of the mandible. The branches of the maxillary artery include the deep auricular artery, middle meningeal, inferior alveolar, deep temporal, buccal, infraorbital and posterior superior alveolar.
The Pterygoid Venous Plexus is also contained within the infratemporal fossa. This plexus of veins and nerves is located between the temporalis and lateral pterygoid muscles. The key structure is the Mandibular Nerve (CN V3). This enters the infratemporal fossa by the Foramen Ovale. This nerve is responsible for innervation of the muscles of mastication (temporalis, masseter, medial & lateral pterygoids). This nerve also divides into the auriculotemporal, inferior alveolar, lingual and buccal nerves.
One branch of the Maxillary nerve (CN V2) enters the infratemporal fossa, the Posterior Superior Alveolar Nerve.
The Otic Ganglion is a parasympathetic component of the glossopharyngeal nerve (CN IX). It is found medially to the foramen ovale. It is the secretory innervation for the parotid gland.
The Foramen Spinosum also opens into this fossa. It contains the middle meningeal artery and vein and the nervus spinosum, a branch of the mandibular nerve
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