Final answer:
The External (Lateral) Pterygoid muscle aids in lateral excursion and opening of the mouth, essential for chewing, and attaches to the lateral pterygoid plate of the sphenoid bone.
Step-by-step explanation:
The function of the External (Lateral) Pterygoid muscle is to assist in the movement of the mandible, specifically in lateral excursion and in opening the mouth. This muscle is unique among the muscles of mastication as it helps to protrude the mandible, enabling side-to-side movement, which is essential for chewing function.
Located on the inferior aspect of the skull, the lateral pterygoid attaches to the lateral pterygoid plate of the sphenoid bone, and it works in conjunction with the medial pterygoid muscle to provide the necessary movements of the mandible for the efficient manipulation of food in the mouth.