of the articular eminence is to limit the forwards movement of the condyle. The ligament directly associated with the TMJ is the temporomandibular ligament, also termed the lateral ligament, which really is a thickening of the lateral aspect of the fibrous capsule. The stylomandibular ligament and the sphenomandibular ligament are not directly associated with the joint capsule. Together, these ligaments act to restrict the extreme movements of the joint. Muscles of mastication The muscles of mastication are paired on each side and work together to produce the movements of the mandible. The main muscles involved are the masseter, temporalis and medial and lateral pterygoid muscles. They can be thought of in terms of the directions they move the mandible, with most being involved in more than one type of movement due to the variation in the orientation of muscle fibers within some of these muscles. Protrusion – Lateral and medial pterygoid. Retraction – Posterior fibers of temporalis (and the digastric and geniohyoid muscles to a lesser extent). Elevation – Anterior and middle fibers of temporalis, the superficial and deep fibers of masseter and the medial pterygoid. Lateral movements – Medial and lateral pterygoid (the ipsilateral temporalis and the pterygoid muscles of the contralateral side pull the mandible to the ipsilateral side). Each lateral pterygoid muscle is composed of 2 heads, the upper or superior head and the lower or inferior head. The lower head originates from the lateral surface of the lateral pterygoid plate and inserts at a depression on the neck of mandibular condyle, just below the articular surface, termed the pterygoid fovea. The upper head originates from the infratemporal surface and the infratemporal crest of the greater wing of the sphenoid bone. The upper head also inserts at the fovea, but a part may be attached directly to the joint capsule and to the anterior and medial borders of the articular disc. The 2 parts of lateral pterygoid have different actions. The lower head contracts during mouth opening, and the upper head contracts during mouth closing. The function of the lower head is to steady the articular disc as it moves back with the condyle into the articular fossa. It is relaxed during mouth closure. Mechanisms of symptoms Joint noises Noises from the TMJs are a symptom of dysfunction of these joints. The sounds commonly produced by TMD are usually described as a "click" or a "pop" when