kyynärpäien

Kyynärpäien (elbows) are the hinge joints at the junction of the upper arm and forearm that allow movement between the humerus, radius, and ulna. They enable bending and straightening of the forearm and, through the proximal radioulnar joint, rotation of the forearm. The elbows transmit loads from the hand to the upper limb and contribute to many daily tasks and athletic activities.

Anatomy and structure: The elbow comprises three joints that share a common capsule: the humeroulnar joint (primary flexion–extension), the humeroradial joint, and the proximal radioulnar joint (pronation–supination). The bones involved include the distal end of the humerus and the proximal ends of the radius and ulna. Stability comes from ligaments such as the ulnar collateral ligament on the inner side and the radial collateral ligament on the outer side, as well as the annular ligament that encircles the head of the radius. The joint is surrounded by a fibrous capsule, seeded with synovial tissue, and protected by bursae and an interosseous membrane between the forearm bones. Muscles acting across the elbow include the flexors (biceps brachii, brachialis, brachioradialis) and extensors (triceps brachii), with pronator teres and supinator supporting forearm rotation.

Movement and variation: Primary movements are flexion, extension, and forearm rotation (pronation and supination). A small carrying angle typically exists, aiding object manipulation and load transfer. Nerve supply mainly involves the musculocutaneous and radial nerves, with other nerves providing sensory innervation.

Clinical relevance: Common issues include fractures of the distal humerus or radial head, elbow dislocations, tendinopathies such as lateral or medial epicondylitis, olecranon bursitis, and arthritis. In children, nursemaid’s elbow is a typical radial head subluxation. Treatment ranges from rest, immobilization, and physical therapy to surgical intervention for unstable injuries or degenerative disease. Prevention focuses on gradual conditioning, proper technique in sports, and protective measures to minimize acute trauma.