The shoulder is a complex joint with an amazing range of motion through which run all the nerves and blood vessels of the upper extremity. It is one of the more vulnerable joints of the body to traumatic or repetitive strain injury. Like any joint, it is subject to degenerative change from ‘wear and tear’ in the form of osteoarthritis. This type of shoulder pain increases with age and is accelerated by a history of traumatic injury or after shoulder surgery. The joint is held together with ligaments connecting the long bone of the arm to your shoulder blade. Important tendons of the arm and shoulder cross over it. The great range of motion of the healthy joint can, through repetitive strain or trauma, cause injury to these ligaments and tendons as well as to the shoulder cartilage resulting in pain and loss of range of motion.
Shoulder pain requires a careful diagnosis and can be confusing. Symptoms of pain and discomfort that are experienced as coming from the shoulder may actually be a ‘referred’ pain coming from another source such as the neck. Shoulder pain that actually comes from the joint typically worsens with activity or movement involving the shoulder. Shoulder pain that is referred from another source does not worsen with shoulder movement.
Arthritic shoulder pain is usually a dull, aching pain that is increased with shoulder motion and accompanied by a loss of range of motion. Shoulder pain after a fall or other trauma is more sudden in onset and can have the added sensation of a ‘dead arm’. The location of pain can be on top, behind, or in the front of the shoulder and commonly radiates over the outside of the upper arm but usually not past the elbow. Reaching activities commonly cause pain, especially above the shoulder or behind the back. Damage to the cartilage of the socket of the joint known as the labrum can cause a sense that the shoulder is ‘slipping’ or ‘sliding’ more than normal. Patients usually avoid lying on the side of the painful shoulder or wake if they roll onto it while sleeping.
Shoulder pain results from sudden trauma, repetitive strain or over-use injury, or simply degenerative wear and tear with age. Trauma to the shoulder from a fall onto an outstretched arm or sudden blow to the shoulder can result in dislocation or separation of the shoulder. In a dislocation, the ball joint of the shoulder is forced out of the socket. This can cause damage to the cartilage ‘cup’ of the socket known as the labrum as well as bony injury on either side of the joint. A shoulder separation involves the small joint between the clavicle and the shoulder blade. Both injuries usually involve ligamentous injuries and, possibly, bone fractures. Tendonitis refers to inflammation of the tendons that cross the shoulder joint and is caused by irritation of the tendons usually from repetitive shoulder activity. Weakness in the shoulder muscles can increase instability in the shoulder which can result in tendonitis. The most commonly affected tendons in the shoulder are the four rotator cuff tendons and one of the biceps tendons. The rotator cuff is made up of four small muscles and their tendons that cover the head of your upper arm bone and keep the shoulder located in the socket. Your rotator cuff helps provide shoulder motion and stability. The rotator cuff tendons are sensitive to repetitive reaching activities especially reaching overhead and throwing activities both of which can cause rotator cuff syndrome otherwise known as ‘impingement syndrome’. Bursitis occurs when the small fluid filled sacs -“bursae”-that reduce friction and act as cushions, become inflamed. Sometimes, excessive use of the shoulder for work or sports that include throwing activities leads to inflammation and swelling of the bursa between the rotator cuff and a part of the shoulder blade. Bursitis often occurs along with rotator cuff tendonitis and is quite painful even making routine daily activities like combing your hair and brushing your teeth painful and difficult. Tendon tears can result from injury or degenerative changes that occur with age, or even excessive long term overuse. The rotator cuff and biceps tendon injuries are among the most common of these injuries. Shoulder instability can also cause shoulder pain. Shoulder instability implies there is more than normal motion in the shoulder joint and is often the result of shoulder dislocation that injures ligaments or joint capsule. Arthritis begins in the shoulder cartilage and progresses to underlying bone. It is the result of age and “wear and tear”. Shoulder osteoarthritis can cause shoulder pain, swelling and stiffness. Shoulder osteoarthritis may be related to sports or work injuries which accelerate degeneration in the joint. Shoulder impingement occurs when the top of the shoulder blade puts pressure on the underlying soft tissues as the arm is lifted away from your body. Impingement may actually result in bursitis or tendonitis and can result in a tear of the rotator cuff.