Annular ligament

Annular Ligament

The annular ligament is a strong band of fibers that encircles the head of the radius in the forearm. It maintains the radius bone in its position, allowing it to rotate during forearm pronation and supination.

Anatomy

The annular ligament is a part of the elbow joint complex. It originates from the anterior and posterior margins of the radial notch of the ulna and wraps around the head of the radius, forming a ring-like structure. The ligament is attached to the ulna both anteriorly and posteriorly, creating a snug fit for the radial head.

Function

The primary function of the annular ligament is to stabilize the proximal radioulnar joint, which is crucial for the rotation of the forearm. It holds the radius close to the ulna and allows the radius to rotate during pronation (rotation of the forearm so that the palm faces downwards) and supination (rotation of the forearm so that the palm faces upwards).

Clinical Significance

Injury to the annular ligament can lead to a condition known as nursemaid's elbow, also known as radial head subluxation. This is a common injury in children where the radius slips out of the annular ligament, causing pain and loss of function in the affected arm. Treatment typically involves a reduction maneuver performed by a healthcare professional.

See Also

• Elbow
• Radius (bone)
• Ulna
• Nursemaid's elbow