The temporal fossa is a narrow fan-shaped space that covers the lateral surface of the skull. Boundaries
its upper margin is defined by a pair of temporal lines that arch across the skull from the zygomatic process of the frontal bone to the supramastoid crest of the temporal bone; it is limited laterally by the temporal fascia, which is a tough fanshaped aponeurosis overlying the temporalis muscle and attached by its outer margin to the superior temporal line and by its inferior margin to the zygomatic arch; anteriorly, it is limited by the posterior surface of the frontal process of the zygomatic bone and the posterior surface of the zygomatic process of the frontal bone, which separate the temporal fossa behind from the orbit in front; its inferior margin is marked by the zygomatic arch laterally and by the infratemporal crest of the greater wing of the sphenoid medially between these two features, the floor of the temporal fossa is open medially to the infratemporal fossa and laterally to the region containing the masseter muscle.
The major structure in the temporal fossa are the temporalis muscle. Temporalis Origin: The temporalis muscle is a large fan-shaped muscle that fills much of the temporal fossa. It originates from the bony surfaces of the fossa superiorly to the inferior temporal line and is attached laterally to the surface of the temporal fascia. Insertion: The more anterior fibers are oriented vertically while the more posterior fibers are oriented horizontally. The fibers converge inferiorly to form a tendon, which passes between the zygomatic arch and the infratemporal crest of the greater wing of the sphenoid to insert on the coronoid process of the mandible. Nerve Supply: The temporalis is supplied by the deep temporal branches of the mandibular nerve ( V3 ). Blood supply of the temporalis is by deep temporal arteries, which travel with the nerves, and the middle temporal artery, which penetrates the temporal fascia at the posterior end of the zygomatic arch. Actions: Temporalis is a powerful elevator of the mandible. Because this movement involves posterior translocation of the head of the mandible from
the articular tubercle of the temporal bone and back into the mandibular fossa, temporalis also retracts the mandible or pulls it posteriorly. In addition, temporalis participates in side-to-side movements of the mandible. Deep Temporal Nerve The deep temporal nerves, usually two in number, originate from the anterior trunk of the mandibular nerve [V3] in the infratemporal fossa. They pass superiorly and around the infratemporal crest of the greater wing of the sphenoid to enter the temporal fossa deep to the temporalis muscle, and supply the temporalis muscle. Zygomaticotemporal nerve The zygomaticotemporal nerve is a branch of the zygomatic nerve. The zygomatic nerve is a branch of the maxillary nerve [V2], which originates in the pterygopalatine fossa. The zygomaticotemporal nerve enters the temporal fossa through one or more small foramina on the temporal fossa surface of the zygomatic bone. Branches of the zygomaticotemporal nerve pass superiorly between the bone and the temporalis muscle to penetrate the temporal fascia and supply the skin of the temple. Deep Temporal Arteries Normally two in number, these vessels originate from the maxillary artery in the infratemporal fossa and travel with the deep temporal nerves around the infratemporal crest of the greater wing of the sphenoid to supply the temporalis muscle. They anastomose with branches of the middle temporal artery Middle Temporal Artery The middle temporal artery originates from the superficial temporal artery just superior to the root of the zygomatic arch between this structure and the external ear. It penetrates the temporalis fascia, passes under the margin of the temporalis muscle, and travels superiorly on the deep surface of the temporalis muscle. The middle temporal artery supplies temporalis and anastomoses with branches of the deep temporal arteries.