The acromioclavicular joint (AC joint) is a joint located in the shoulder region, where the clavicle (collarbone) meets the acromion (a bony projection of the scapula or shoulder blade). It is a synovial joint, which means it is surrounded by a joint capsule and contains synovial fluid to lubricate the joint surfaces.
The AC joint is responsible for connecting the shoulder girdle to the axial skeleton, allowing for a wide range of arm and shoulder movements. It is also responsible for absorbing and distributing the forces that are applied to the shoulder region.
Injuries to the AC joint are common, particularly in individuals who participate in contact sports or activities that involve overhead movements of the arms. The most common type of AC joint injury is a sprain or separation, which occurs when the ligaments that hold the joint together are stretched or torn. Symptoms of an AC joint sprain may include pain, swelling, and tenderness in the shoulder region, as well as difficulty moving the arm.
Treatment for an AC joint injury typically involves a combination of rest, ice, compression, and elevation to reduce pain and swelling. In some cases, a sling or other supportive device may be used to immobilize the joint and promote healing. More severe cases may require surgery to repair or reconstruct the damaged ligaments.
In addition to injuries, the AC joint can also be affected by degenerative conditions such as osteoarthritis, which can cause pain, stiffness, and limited range of motion in the shoulder region. Treatment for AC joint osteoarthritis may involve medications, physical therapy, and in some cases, surgery to replace the damaged joint.
Overall, the acromioclavicular joint plays an important role in shoulder function and mobility, and injuries or conditions affecting this joint can have a significant impact on daily activities and quality of life.