In humans, the temporalis muscle arises from the
temporal fossa and the deep part of
temporal fascia. This is a very broad area of attachment. It passes medial to the
zygomatic arch. It forms a tendon which inserts onto the
coronoid process of the mandible, with its insertion extending into the
retromolar fossa posterior to the most distal mandibular molar. In other mammals, the muscle usually spans the dorsal part of the skull all the way up to the medial line. There, it may be attached to a
sagittal crest, as can be seen in early hominins such as
Paranthropus aethiopicus. The temporalis muscle is covered by the
temporal fascia, also known as the temporal aponeurosis. This fascia is commonly used in
tympanoplasty, or surgical reconstruction of the eardrum. The temporalis muscle is accessible on the
temples, and can be seen and felt
contracting while the jaw is clenching and unclenching.
Blood supply The muscle receives its blood supply from the
deep temporal arteries which anastomose with the
middle temporal artery.
Nerve supply As with the other muscles of mastication, control of the temporal muscle comes from the third (mandibular) branch of the
trigeminal nerve. Specifically, the muscle is supplied by the
deep temporal nerves. At least 6 smaller branches recruit muscle fibres the most when each has the maximal leverage.
Development The temporalis muscle is derived from the
first pharyngeal arch in development.
Variation The temporalis muscle has a complex structure.
Sarcomeres are a consistent length, but larger
muscle fibres vary in length in the muscle and between people. ==Function==