Musculus pterygoideus externus, also known as the lateral pterygoid muscle, is a muscle located in the head and neck region of the human body. It is one of the four muscles that make up the muscles of mastication (chewing) and plays a crucial role in the opening and lateral movement of the jaw.
The term "musculus pterygoideus externus" is derived from Latin, where "musculus" means muscle, "pterygoideus" refers to the pterygoid process of the sphenoid bone to which the muscle attaches, and "externus" denotes the muscle's position external to the temporomandibular joint.
This muscle has a flat, fan-like shape and is situated on each side of the head. It arises from two distinct heads: the upper or superior head originates from a depression on the greater wing of the sphenoid bone, while the lower or inferior head arises from the lateral surface of the lateral pterygoid plate of the sphenoid bone. Both heads then converge and insert onto the articular disc of the temporomandibular joint.
The action of the musculus pterygoideus externus is to protract or protrude the mandible, helping to open the jaw. Additionally, it plays a vital role in the lateral movements of the jaw, such as during chewing and grinding food. It works in coordination with the other muscles of mastication to facilitate the complex movements required for efficient chewing and speaking.
In summary, the musculus pterygoideus externus is a significant muscle involved in the opening and lateral motions of the jaw, making it crucial for chewing and speaking functions.
