The function 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.
Specifically, Costen believed that the cause of TMD was mandibular over-closure, recommending a treatment revolving around building up the bite. The eponym "Costen syndrome" became commonly used shortly after his initial work, but in modern times it has been dropped, partially because occlusal factors are now thought to play little, if any, role in the development of TMD, and also because ear problems are now thought to be less associated with TMD. Other historically important terms that were used for TMD include "TMJ disease" or "TMJ syndrome", which are now rarely used. == References ==