bone covers the articular surfaces of the human temporomandibular joint.
bone covers the articular surfaces of the human temporomandibular joint.
what type of tissue covers the articular surfaces of the human temporomandibular joint?
bone
the temporomandibular joints are the dual articulation of the mandible with the skull. each tmj is classed as a "ginglymoarthrodial" joint since it is both a ginglymus (hinging joint) and an arthrodial (sliding) joint, and involves the condylar process of the mandible below, and the articular fossa (or glenoid fossa) of the temporal bone above. between these articular surfaces is the articular disc (or meniscus), which is a biconcave, transversely oval disc composed of dense fibrous connective tissue. each tmj is covered by a fibrous capsule. there are tight fibers connecting the mandible to the disc, and loose fibers which connect the disc to the temporal bone, meaning there are in effect 2 joint capsules, creating an upper joint space and a lower joint space, with the articular disc in between. the synovial membrane of the tmj lines the inside of the fibrous capsule apart from the articular surfaces and the disc. this membrane secretes synovial fluid, which is both a lubricant to fill the joint spaces, and a means to convey nutrients to the tissues inside the joint. behind the disc is loose vascular tissue termed the "bilaminar region" which serves as a posterior attachment for the disc and also fills with blood to fill the space created when the head of the condyle translates down the articular eminence. due to its concave shape, sometimes the articular disc is described as having an anterior band, intermediate zone and a posterior band. when the mouth is opened, the initial movement of the mandibular condyle is rotational, and this involves mainly the lower joint space, and when the mouth is opened further, the movement of the condyle is translational, involving mainly the upper joint space. this translation movement is achieved by the condylar head sliding down the articular eminence, which constitutes the front border of the articular fossa. 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.
temporomandibular joint dysfunction
frequently, tmd has been treated as a single syndrome, but the prevailing modern view is that tmd is a cluster of related disorders with many common features. indeed, some have suggested that, in the future, the term "tmd" may be discarded as the different causes are fully identified and separated into different conditions. sometimes, "temporomandibular joint dysfunction" is described as the most common form of temporomandibular disorder, whereas many other sources use the term "temporomandibular disorder synonymously", or instead of the term "temporomandibular joint dysfunction". in turn, the term "temporomandibular disorder" is defined as "musculoskeletal disorders affecting the temporomandibular joints and their associated musculature. it is a collective term which represents a diverse group of pathologies involving the temporomandibular joint, the muscles of mastication, or both". another definition of temporomandibular disorders is "a group of conditions with similar signs and symptoms that affect the temporomandibular joints, the muscles of mastication, or both." "temporomandibular disorder" is a term that creates confusion since it refers to a group of similarly symptomatic conditions, whilst many sources use the term "temporomandibular disorders" as a vague description, rather than a specific syndrome, and refer to any condition which may affect the temporomandibular joints (see table). the temporomandibular joint is susceptible to a huge range of diseases, some rarer than others, and there is no implication that all of these will cause any symptoms or limitation in function at all.
temporomandibular joint dysfunction