Which of the following muscles is used for opening the mouth ? A. Medial pterygoid B. Temporalis C. Lateral pterygoid D. Masseter
The temporal muscle is the most powerful muscle of the temporomandibular joint. The temporal muscle can be divided into two functional parts; anterior and posterior. The anterior portion runs vertically and its contraction results in elevation of the mandible (closing the mouth). The posterior portion has fibers which run horizontally and contraction of this portion results in retrusion of the mandible
Unlike the other three muscles of mastication, the lateral pterygoid is the only muscle of mastication that assists in depressing the mandible (opening the jaw).
The function of the masseter is to elevate the mandible, raising the lower jaw. Elevation of the mandible occurs during the closing of the jaws.
