Tuesday 27 April 2004
Articulations. Adj. articular
Definition: A joint is the location at which two or more bones make contact. They are constructed to allow movement (except for skull bones) and provide mechanical support, and are classified structurally and functionally
- joined by cartilage
- not directly joined
- the bones have a synovial cavity and are united by the dense irregular connective tissue that forms the articular capsule that is normally associated with accessory ligaments.
Joints can also be classified functionally, by the degree of mobility they allow:
synarthrosis - permits little or no mobility.
- Most synarthrosis joints are fibrous joints (e.g., skull sutures).
- permits slight mobility.
- Most amphiarthrosis joints are cartilaginous joints (e.g., vertebrae).
- permits a variety of movements.
- All diarthrosis joints are synovial joints (e.g., shoulder, hip, elbow, knee, etc.), and the terms "diarthrosis" and "synovial joint" are considered equivalent by Terminologia Anatomica.
Joints can also be classified based on their anatomy or on their biomechanical properties. According to the anatomic classification, joints are subdivided into simple and compound, depending on the number of bones involved, and into complex and combination joints:
Simple Joint: 2 articulation surfaces (e.g. shoulder joint, hip joint)
Compound Joint: 3 or more articulation surfaces (e.g. radiocarpal joint)
Complex Joint: 2 or more articulation surfaces and an articular disc or meniscus (e.g. knee joint)
The joints may be classified anatomically into the following groups:
Articulations of hand
Articulations of foot
pathology of joints
Articular and Inflammatory Disorders by Daria Brooks, MD; James Jelinek, MD; Norio Azumi, MD at WCI, DC