polviniveltä

Polviniveltä, also known as the elbow joint, is a complex hinge joint located at the junction of the humerus (upper arm bone) and the ulna (one of the two bones in the forearm). It is a synovial joint, meaning it is lined with a smooth, lubricating substance called synovial fluid, which reduces friction between the bones. The elbow joint is crucial for various movements, including flexion (bending the elbow), extension (straightening the elbow), and supination (rotating the forearm).

The elbow joint is composed of three bones: the humerus, the ulna, and the radius. The humerus articulates with the ulna at the trochlear notch, and with the radius at the radial fossa. The ulna and radius are connected by the interosseous membrane, which helps stabilize the joint. The elbow joint is also supported by several ligaments, including the radial collateral ligament, the ulnar collateral ligament, and the annular ligament, which reinforces the joint and prevents excessive movement.

The elbow joint is innervated by the radial nerve, which supplies sensation to the skin over the back of the forearm and the lateral aspect of the hand. The joint is also innervated by the median nerve, which supplies sensation to the skin over the palm and the lateral three and a half digits of the hand. The elbow joint is a common site for injuries, such as sprains, strains, and fractures, particularly in athletes and individuals who engage in activities that involve repetitive or forceful movements of the arm. Proper warm-up and stretching exercises can help prevent injuries to the elbow joint.