The ligamentum annulare radii, also known as the annular ligament of radius, is a fibrous band or strap-like structure located within the human forearm. It is specifically situated around the head of the radius bone, which is one of the two bones in the forearm, responsible for supporting and facilitating forearm movements.
This ligament functions as a strong, flexible ring that encircles the head of the radius bone, helping to stabilize and hold it in proper alignment with the ulna, the other bone in the forearm. It forms a continuous loop around the radial head and attaches to the ulna bone and other surrounding structures such as the radial notch.
The ligamentum annulare radii acts as a critical component in maintaining the stability of the forearm joint, allowing rotational movements between the radius and ulna bones while preventing excessive or abnormal rotation that could lead to injury. It serves as a protective structure, helping to keep the radius bone securely in its place during various activities such as forearm rotation or gripping objects.
Injury to the ligamentum annulare radii can cause a condition called annular ligament tear or radial head subluxation, which can result in pain, limited range of motion, and instability in the forearm joint. Treatment for a damaged or torn ligamentum annulare radii usually involves a combination of conservative measures such as rest, immobilization, physical therapy, and in more severe cases, surgical repair or reconstruction.
