Open

Digastric
Posted On March 19 2019. Updated On March 19 2019.
The digastric muscle (also digastricus) is a small muscle located under the jaw. When the digastric muscle contracts, it acts to elevate the hyoid bone. If the hyoid is being held in place (by the infrahyoid muscles), it will tend to depress the mandible (open the mouth).
Lateral Pterygoid
Posted On March 19 2019. Updated On March 19 2019.
The lateral pterygoid (or external pterygoid) is a muscle of mastication with two heads. It lies superiorly to the medial pterygoid.
Platysma
Posted On March 19 2019. Updated On March 19 2019.
The platysma is a superficial muscle that overlaps the sternocleidomastoid. It is a broad sheet arising from the fascia covering the upper parts of the pectoralis major and deltoid; its fibers cross the clavicle, and proceed obliquely upward and medially along the side of the neck.