jawmuscle

The jawmuscle refers to the group of muscles responsible for movements of the mandible during chewing and speaking. The primary jaw muscles are the masseter, temporalis, and the two pterygoids (lateral and medial). They are innervated mainly by the mandibular division of the trigeminal nerve (cranial nerve V3). Blood supply comes from branches of the maxillary and facial arteries.

Masseter is a strong elevating muscle that originates from the zygomatic arch and inserts on the angle and lower ramus of the mandible, primarily helping to close the jaw. The temporalis is a broad muscle on the temporal fossa that inserts at the coronoid process and the anterior edge of the mandibular ramus, contributing to jaw elevation and, with fibers near the back, retraction. The lateral pterygoid originates from the sphenoid bone and inserts into the articular disc and the neck of the mandible; it protrudes the jaw and assists in opening and side-to-side movements. The medial pterygoid arises from the pterygoid plates and inserts on the medial surface of the mandible, elevating the jaw and aiding in protrusion. Collectively, these muscles coordinate to close the jaw, grind food, and enable rapid chewing motions.

Clinically, dysfunction of the jawmuscles can be involved in temporomandibular joint disorders (TMD), jaw pain, limited range of motion, or bruxism (teeth grinding). Evaluation may include palpation, imaging, and sometimes electromyography. Management is typically conservative, including patient education, soft diets, heat or cold therapy, physical therapy, occlusal splints, and medications for pain and muscle relaxation; surgery is uncommon and reserved for severe cases.