Sarananivelistä

Sarananivelistä refers to a type of hinge joint in anatomy. This joint allows for movement primarily in one plane, much like a door hinge. The most common example of a sarananivelistä is found in the elbow, where it permits flexion and extension of the forearm relative to the upper arm. Another significant example is the knee joint, which also exhibits hinge-like motion, although it has some capacity for rotation when flexed. The structure of a sarananivelistä involves the articulation of two bony surfaces, typically with a rounded or cylindrical projection fitting into a corresponding trough or socket. This specific configuration restricts movement to a single axis, preventing sideways or rotational motion. The smooth surfaces of the articular cartilage and the presence of synovial fluid within the joint capsule facilitate this unidirectional gliding or swinging motion with minimal friction. Ligaments play a crucial role in stabilizing the sarananivelistä, providing support and limiting excessive or abnormal movements. Injuries to these joints can significantly impair mobility, and conditions like osteoarthritis can affect the cartilage, leading to pain and reduced function.