Shoulder injuries to the glenohumeral joint, or ball joint, cause great discomfort and significantly affect the range of motion of the rotator cuff. Most people with these injuries need to seek medical attention for diagnosis, pain relief and treatment.
In normal shoulder posture, the ball of the humerus, or upper arm bone, is seated against the glenoid cavity of the scapula, or shoulder blade, to form the ball joint. A healthy joint is covered by the labrum, a cartilage collar that helps stabilize the joint.
Cartilage Tear
Cartilage tears to the labrum occur during strenuous overhead movement of the rotator cuff, such as when serving in tennis. These shoulder injuries can occur suddenly, or gradually through overuse of the ball joint. Falls, heavy lifting and other shoulder trauma can also cause cartilage to tear.
University Sports Medicine lists symptoms of labral tears as shoulder pain; muscular weakness in the shoulder and arm; difficulty raising the arm overhead; and audible clicks or grinding during movement. The American Academy of Orthopaedic Surgeons (AAOS) notes that the shoulder may feel unstable as well, which it is. The cartilage that helped fill the glenoid cavity may have shifted, leaving more space around the joint.
Shoulder Arthritis
Osteoarthritis and rheumatoid arthritis are shoulder injuries associated with aging and also with overuse of the ball joint, according to the AAOS. Years of movement wear down the bone tissue and its protective cartilage and bursa. As the joint degenerates, shoulder pain increases. Instability in the joint also increases, raising the risk of dislocation or other injuries.
This arthritic action can occur among younger athletes, such as weightlifters, who make repeated, stressful cross-body motions. It can also arise from a previous injury to the shoulder bones or soft tissue. The AAOS notes that shoulder pain will localize in the back of the shoulder and may flare due to weather changes.
Shoulder Dislocation
A dislocation is one of the most traumatic shoulder injuries. It compromises the integrity of the entire rotator cuff by damaging its supportive structure. The ball of the humerus may be forcibly separated from the glenoid socket by a violent twist, a blow from a fall, or from forceful contact with a person or object.
University Sports Medicine notes that some people are vulnerable to dislocations, either genetically or through conditions of shoulder instability, such as a torn labrum or arthritic degeneration. Extreme shoulder pain and visible deformity will be immediate symptoms requiring medical care. Ligaments, tendons, cartilage, bones and nerves may also sustain damage.
