Annulaariligamentti

Annulaariligamentti, or the annular ligament, is a strong band of fibrous tissue that encircles the head of the radius bone in the elbow joint. Its primary function is to hold the radial head in place within a notch on the ulna bone, known as the radial notch. This articulation allows the radius to rotate freely during pronation and supination of the forearm, movements essential for everyday activities such as turning a doorknob or using a screwdriver.

The annular ligament plays a crucial role in maintaining the stability of the elbow joint, particularly during rotational movements. It forms part of the proximal radioulnar joint, ensuring that the radius and ulna remain properly aligned. The ligament originates from the anterior and posterior borders of the radial notch on the ulna and inserts onto the neck of the radius, effectively creating a ring that grips the radial head.

Injury to the annular ligament can lead to significant elbow pain and instability. A common condition involving this ligament, particularly in children, is annular ligament displacement, often referred to as "pulled elbow" or "nursemaid's elbow." This occurs when the ligament is partially pulled away from its attachment to the radial neck, often due to a sudden upward pull on the child's arm. In adults, tears or sprains of the annular ligament can result from direct trauma or overuse. Treatment typically involves rest, pain management, and sometimes immobilization, with surgical intervention reserved for severe cases or recurrent instability.