Corpus: Temporal muscle

The temporalis muscle is a skeletal muscle that is part of the superficial muscles of mastication.

The temporalis muscle originates over a large area from the outer side of the temporal facies of the temporal bone scale between the inferior temporal line and the infratemporal crest. It fills the temporal and infratemporal fossa. The anterior sections originate from the zygomatic and frontal bones and the greater sphenoid bone (ala major ossis sphenoidalis). The dorsal sections originate from the parietal bone near the lambdoid sutura. Another deep medial muscle section originates at the base of the skull between the infratemporal crest and the entrance to the pterygopalatine fossa.

The muscle is covered by a strong fascia (fascia temporalis profunda), which also serves as the muscle origin.

The extensive muscle fibres of the temporalis muscle bundle together to form a strong tendon that attaches to the coronoid process and the temporal crest of the mandible. Furthermore, tendon bundles radiate into the fascia of the buccinator muscle (fascia buccotemporalis).

The temporalis muscle is innervated by the nervi temporales profundi, which arise from the mandibular nerve (V3).

The temporalis muscle, together with the masseter muscle and the medial pterygoid muscle, is responsible for closing the jaw (adduction). The temporalis muscle is therefore also involved in closing the mouth. In addition, the deep medial sections pull the lower jaw forwards (protrusion), while the posterior sections pull it dorsally (retrusion). Individually, the temporalis muscle is the strongest closing muscle of the jaw.

When contracted on one side, the caput mandibulae of the balance side shifts ventrally, which supports the grinding movement.