Diarthroosi

Diarthroosi, commonly referred to as a diarthrosis or synovial joint, is a type of articulation that permits substantial freedom of movement between the bones it connects. The defining feature is a synovial joint cavity enclosed by a fibrous capsule, lined by a synovial membrane, and surrounded by accessory ligaments. The joint surfaces are covered by articular cartilage and are lubricated by synovial fluid. Additional structures such as menisci, discs, or labra may modify congruence and distribution of load.

Diarthroses are the most mobile type of joints and contrast with synarthroses (immovable) and amphiarthroses (slightly movable). They typically allow multiple planes of motion and are classified by the shape of their articulating surfaces and movements into six major types: ball-and-socket, hinge, pivot, condyloid, saddle, and plane joints. The ligaments and the surrounding muscles provide stability and control movement.

Common examples include the shoulder and hip joints (ball-and-socket), elbow (hinge), wrist (condyloid and plane aspects), radioulnar joints (pivot), and the joints of the jaw (hinge and plane components).

Developmentally, diarthroses form within limbs as limb bones elongate and mesenchymal condensations differentiate into cartilage and synovial tissue. Functionally, they support activities ranging from gross locomotion to fine motor tasks.

Clinically, diarthroses are frequent sites of injury and disease. Traumatic dislocations, sprains, and meniscal tears may disrupt function. Degenerative conditions such as osteoarthritis, inflammatory arthritides like rheumatoid arthritis, and synovitis can impair movement and cause pain.