What is TMJ?
Tuesday, December 8th, 2009
The temporomandibular joint is the joint of the jaw. This is frequently referred to as TMJ. There are two temporomandibular joints, one on either side of the head that work in unison. The TMJ name is derived from the two bones which form the joint of the upper temporal bone which is part of the skull, and the lower jaw bone which is called the mandible.
The specific feature of the temporomandibular joint is the disc. The disc is composed of fibrocartilagenous tissue, like the flexible elastic cartilage of the ear, which is positioned between the two bones that form the joint.
The temporomandibular joints are one of the only two synovial joints in the human body. The synovial joints divides each portion of the jaw into two specific compartments. The lower joint compartment is formed by the mandible and the disc is involved in rotational movement through opening and closing movements.
The upper joint compartment is involved in multiple positioning movements which allows the sliding of the lower jaw forward from side to side. The part of the mandible which connects to the under-surface of the disc and is the part of the temporal bone which also connects to the upper surface of the disk. This is the glenoid ossa – also known as mandibular.
Pain or problems of the temporomandibular joint is commonly referred to as “TMJ”, however, this can be confusing since TMJ is really the name of the joint and Temporomandibular joint disorder is abbreviated as TMD.
TMD is often referred to as a group of problems involving the temporomandibular joints and the muscular-skeletal system of the jaw, including tendons, ligaments, blood vessels, and other tissues associated with them. Some specialists might even include the neck and back while describing problems with temporomandibular joints.