Assistant
Definition
By Gregory R. Waryasz, MD
The annular ligament of the musculoskeletal system is characterized by its location and function.
It is part of the elbow joint. It consists of fibrous dense regular connective tissue of collagen fibers.
Its unique structural feature is that it is a strong ligament that spans from the anterior ulna to the radial notch encircling the radial head. The deep surface of the annular ligament is lined with synovial tissue. This continues into the proximal radioulnar joint to allow for movement of the radial head freely without tearing the surrounding tissues.
The annular ligament as well as all other bones, muscles, and ligaments of the body are derived of mesodermal origin in the embryo.
The function of the annular ligament is to stabilize the proximal radioulnar joint and allow for movement of the radial head for pronation and supination.
Common diseases include ligament tears and dislocation/subluxation.
Nursemaid’s elbow is a condition of subluxation of the radial head associated from axial traction. This can occur when parents hold their children in the air by the hands or forearm.
Commonly used diagnostic procedures include clinical history, physical exam, x-ray, and MRI.
It is usually treated with physical therapy and NSAIDs. Surgery can be performed if there is significant laxity in the elbow.
References
Elstrom J, Virkus W, Pankovich (eds), Handbook of Fractures (3rd edition), McGraw Hill, New York, NY, 2006.
Koval K, Zuckerman J (eds), Handbook of Fractures (3rd edition), Lippincott Williams & Wilkins, Philadelphia, PA, 2006.
Lieberman J (ed), AAOS Comprehensive Orthopaedic Review, American Academy of Orthopaedic Surgeons, 2008.
Moore K, Dalley A (eds), Clinically Oriented Anatomy (5th edition), Lippincott Williams & Wilkins, Philadelphia, PA, 2006.