External pterygoid muscle

External pterygoid muscle

The external pterygoid muscle (shown in red) is one of the muscles of mastication. Image from Gray's Anatomy.

The external pterygoid muscle (or lateral pterygoid muscle) is one of the four muscles of mastication and is primarily responsible for opening the jaw and moving it side to side. It is a short, thick muscle that is located on the side of the face, just below the temporal bone and in front of the ear.

Structure

The external pterygoid muscle originates from the lateral surface of the pterygoid process of the sphenoid bone and the infratemporal surface and infratemporal crest of the greater wing of the sphenoid bone. It inserts into the neck of the mandible and the articular disc of the temporomandibular joint.

Function

The external pterygoid muscle acts to protrude the mandible, opening the mouth, and moves the mandible from side to side. It also assists in the elevation of the mandible.

Clinical significance

Dysfunction of the external pterygoid muscle can lead to temporomandibular joint disorder, a condition characterized by pain and limited movement of the jaw.

See also

• Internal pterygoid muscle
• Muscles of mastication
• Temporomandibular joint