The temporalis muscle is a thin, fan-shaped muscle situated within the temporal fossa of the skull. Along with the medial pterygoid, lateral pterygoid and masseter muscles, it belongs to the group masticatory muscles. The temporalis muscle runs superficially, from the temporal bone to the coronoid process of mandible.
The main function of this muscle is to produce the movements of the mandible at the temporomandibular joint and thus facilitate the act of mastication. Its anterior portion moves the mandible dorsocranially (elevation) while its posterior fibers pull the mandible posteriorly (retrusion).
|Origin||Temporal fossa (up to inferior temporal line), Temporal fascia|
|Insertion||Apex and medial surface of coronoid process of mandible|
|Action||Anterior fibres: Elevates mandible
Posterior part: Retracts mandible
|Innervation||Deep temporal branches (of mandibular nerve (CN V3))|
|Blood supply||Deep temporal branches of maxillary artery, middle temporal branches from superficial temporal artery|
In this article, we will discuss the anatomy and function of the temporalis muscle.
Origin and insertion
The temporalis muscle is a broad muscle that occupies most of the temporal fossa. Its origin point spans the entire surface of the fossa below the temporal line. Additionally, some fibers originate from the temporal fascia as well.
The temporalis muscle is divided into the anterior and posterior parts. The anterior fibers run inferiorly, in an almost vertical direction, while its posterior fibers are directed almost horizontally. Both anterior and posterior fibers converge onto a narrow tendon that runs medial to the zygomatic arch. The tendon inserts onto the apex and medial surface of the coronoid process of mandible.
The temporalis muscle covers the temporal fossa with its deep surface. Superficially, the muscle is covered by the temporal fascia, masseter muscle, subcutaneous tissue and skin. The auriculotemporal, facial and zygomaticotemporal nerves run across the superficial aspect of the temporalis muscle.
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The temporalis muscle receives its innervation from the anterior, middle and posterior deep temporal branches of the anterior trunk of the mandibular nerve (V3).
To expand your knowledge check out our other articles, videos, quizzes and labeled diagrams about the muscles of mastication.
The temporalis muscle is the strongest muscle of the temporomandibular joint and the primary retractor of the mandible. The contraction of the posterior fibers of the temporalis muscle results with the backward movement of the mandible (retrusion). The contraction of its anterior fibers moves the mandible dorsocranially (elevation). In unison, these actions facilitate the closing of the mouth and the approximation of the teeth. Additionally, the unilateral contraction of the temporalis muscle plays an important role in the side-to-side movements of the jaw.
Tension of the temporal muscle can induce pain in the temporal area. Common causes include:
- misalignments of the teeth and jaws
- a prolonged immobilisation (e.g. after a mandibular fracture)
- teeth grinding (bruxism)
- a dental intervention during which the person's mouth had to be open for a long period of time.
Clinically, it is important to rule out an inflammation of the superficial temporal artery, which runs in front of the ear along the zygomatic arch to the temporal area. Vasculitides, such as the giant cell arteritis, frequently involve the superficial temporal artery and cause swelling and massive pain in the temporal area. The diagnosis can be confirmed by a temporal artery biopsy.