Synovialledd

Synovialledd is the term used for a synovial joint, a highly movable articulation found in the limbs and many other parts of vertebrate bodies. These joints create a balance between mobility and stability by enclosing articulating bones within a cavity filled with synovial fluid, which lubricates surfaces and reduces friction during movement.

Structure: Each synovialledd consists of articular cartilage covering the bone ends, a fibrous joint capsule, and an inner synovial membrane that secretes synovial fluid. The capsule is reinforced by ligaments, and in some joints an articular disc or meniscus improves fit and load distribution. Surrounding tissues, such as bursae and tendon sheaths, may further reduce friction and facilitate movement.

Function and types: The presence of a synovial cavity and fluid allows multiple planes and degrees of freedom of movement, ranging from simple gliding to rotation, flexion, extension, and abduction. Synovialledd are classified into six main types by the shape of the articulating surfaces: ball-and-socket, hinge, pivot, condylar, saddle, and plane joints. Examples include the shoulder, knee, elbow, hip, and wrist.

Clinical relevance: Injuries and diseases can impair synovialledd function, causing pain, swelling, and reduced range of motion. Common conditions include osteoarthritis, rheumatoid arthritis, gout affecting synovial joints, and traumatic injuries such as dislocations or ligament tears. Understanding their anatomy helps diagnose joint disorders and plan treatment, which may involve physical therapy, medications, or surgical intervention.