The shoulder is a ball and socket joint. The shoulder joint is made up of three bones: clavicle (collarbone), scapula (shoulder blade), and the humerus (upper arm bone) as well as muscles, ligaments and tendons. The main shoulder joint refers to the glenohumeral joint, which is the humeral head (ball) and the glenoid (socket). Other shoulder joints are the acromioclavicular (AC joint) and the sternoclavicular joint (SC joint). There is also the scapulothoracic articulation. There are two kinds of cartilage in the shoulder joint. There is articular cartilage at the humeral head and the glenoid, which allows the bones to smoothly glide and move on each other throughout shoulder motion. When this type of cartilage starts to wear out (osteoarthritis), the joint can become painful and cause a loss of shoulder motion in all directions. The labrum is a fibrocartilage in the shoulder that is different from articular cartilage. The labrum provides static stability of the shoulder.
The acromioclavicular (AC) joint in the shoulder is a common area for osteoarthritis to develop. The AC joint is the connection between the scapula and the clavicle. Degeneration of the AC joint can be painful and can cause difficulty while using the shoulder for everyday activities.
AC joint arthritis is commonly associated with people who participate in repetitive heavy overhead activities (weightlifting and overhead throwing athletes such as baseball). You do not have to participate in these activities to develop AC joint osteoarthritis.
AC joint sprain (also known as a shoulder separation) is a fairly common injury, especially in certain sports such as football and soccer. When you hear of someone having a “shoulder separation”, this is referring to the AC joint. This is a sprain of the ligaments that provide stability to the AC joint. The AC joint is held in place by the acromioclavicular ligament and coracoclavicular ligaments (conoid and trapezoid). There are various grades of AC joint sprains and most are treated non-operative or may require surgery based on the grade, patient age and activity level.
Adhesive capsulitis (also known as a frozen shoulder) can be a very painful condition and severely limit your shoulder motion. This condition can also last for more than one year. There is no known cause of adhesive capsulitis. Adhesive capsulitis is more common in, but not exclusive to, diabetics and is a clinical diagnosis. Most of the time, this condition can be successfully treated with a diligent daily stretching program, formal physical therapy. There are times that adhesive capsulitis does not resolve with conservative treatment and may require surgery.
A proximal biceps tendon long head rupture involves a complete tear and retraction of the biceps tendon that attaches to the point in the shoulder joint. There is also a short head of the proximal biceps that attaches to a bone off of the scapula called the coracoid. A rupture of the proximal biceps long head will cause a “popeye muscle”. Proximal biceps tendon long head rupture are very common and happens most often in middle-aged people and is usually due to years of wear and tear on the shoulder. An acute proximal biceps long head rupture in younger athletes sometimes occurs during weightlifting or from actions that cause a sudden load on the arm, such as falling on an outstretched arm or a rapid jerking motion of the arm.
Calcific tendonitis of the shoulder happens when a calcium deposit forms in the rotator cuff tendon, most commonly the supraspinatus tendon. The rotator cuff tendon and the area around the calcium deposit can become inflamed and cause fairly significant pain at the shoulder. This condition is fairly common condition and the calcium deposit can typically be seen on plain X-rays. There are times when this condition may need arthroscopic surgery to excise the calcium deposit.
The rotator cuff tendons and/or subacromial bursa can be inflamed and swell with fluid in the bursa and cause pain. The symptoms may start out very mild. These symptoms may include, but not limited to, varying degrees of pain over the lateral side of the arm, sudden pain with lifting and reaching movements and pain at rest. Athletes of overhead sports may have pain with throwing or serving a tennis ball.
As the problem progresses, the symptoms can increase and you may experience night pain, loss of strength and difficulty with simple activities of daily living.
The labrum is a fibrocartilaginous rim that surrounds and attaches to the glenoid and provides stability for the shoulder joint (glenohumeral joint). A labral tear can occur from a glenohumeral joint dislocation or wear and tear over time. For example, activities such as weightlifting place a gradual stretch on the labral, can cause microtrauma to the labrum and a labral tear can develop over time. A labral tear can cause pain, a catching sensation and instability in the shoulder. Most labral tears can be diagnosed with a MRI arthrogram. However, a MRI arthrogram is not 100% accurate and there are times that labral tears are not found until arthroscopic surgery.
Rotator cuff tears can be a variety of shapes and sizes – ranging from small partial tear to massive retracted tears. Treatment is varied based on the nature of the tear and individual differences in pain level, goals, etc. Some rotator cuff tears are asymptomatic and require no treatment. Over 50 % of asymptomatic volunteers over age 60 have a partial or complete rotator cuff tears on a MRI. We treat tears when they are symptomatic and effect someone’s quality of life.
Most rotator cuff tears are the result of wear and tear of the rotator cuff tendon over time. Acute injuries such as falling on an outstretched arm, repetitive or sudden heavy lifting and jerking motion can cause a rotator cuff tear. Patients under 40 years old are more likely to have an acute rotator cuff tear where a patient 60 years and older is more likely to have a degenerative rotator cuff tear.
A shoulder dislocation is an injury to the glenohumeral joint. The most common shoulder dislocation is an anterior dislocation. A posterior dislocation can occur from trauma and is mostly seen in patients after seizures. Inferior shoulder dislocations are very rare and the least common type of shoulder dislocation. The specific type of dislocation is based on the position of the humeral head in relation to the glenoid at the time of the diagnosis. Chronic dislocations over time can lead to bone loss of the glenoid and/or humeral head.
Shoulder instability refers to the glenohumeral joint becoming too loose and therefore can easily slide in and out of the socket. In some cases, the shoulder can become so unstable that the humeral head can slip of out the glenoid with simple activities. Shoulder instability can be from an acute traumatic dislocation, non-traumatic or from generalized ligamentous laxity of the shoulder.
Osteoarthritis is a condition that destroys the smooth articular cartilage of bone or “wear” and “tear”. As the articular cartilage breaks down, it becomes frayed and rough and this can cause shoulder pain. As the articular cartilage breaks down, the space between the humeral head and the glenoid of the shoulder decreases and this can also cause pain and loss of shoulder motion. During shoulder motion, the bones of the glenohumeral joint rub against each other, causing pain and loss of motion. Activity modification and injections can be beneficial. There are times where conservative treatment is not helpful and a shoulder replacement may be indicated for severe glenohumeral joint osteoarthritis.
The scapulothoracic articulation is located where the scapula glides along the chest wall. The soft tissues between the scapula and the chest wall can become inflamed causing popping and pain at this articulation. This can occur from abnormal motion of the scapula, soft tissue inflammation or a benign mass at the articulation.
A winging scapula is associated with damage to the long thoracic nerve which innervates the serratus anterior and causes medial winging of the scapula. There can also be lateral winging of the scapula which is from damage to the spinal accessory nerve which innervates the trapezius muscle. An EMG (Electromyography) may be ordered to evaluate for a nerve injury if this condition is suspected.
Thoracic outlet syndrome (TOS) is a condition symptoms can range from numbness and/or a coldness type feeling in the fingers, pain in shoulder, arm, and/or neck from compression of nerves and/or blood vessels in the upper chest or at the thoracic outlet. There are tests on a physical examination that can be positive which may require further evaluation by a thoracic surgeon.
Suprascapular neuropathy is an injury to a major nerve that innervates 2 rotator cuff muscles in your shoulder. This can occur from an entrapment of a ligament, ganglion cyst which may cause pressure on the nerve, or traction injury. An injury to the suprascapular nerve is confirmed by an EMG.
Frozen Shoulder
External Rotation – Passive StretchReproduced with permission from JF Sarwark, ed: Essentials of Musculoskeletal Care, ed 4. Rosemont, IL, American Academy of Orthopaedic Surgeons, 2010.
Forward Flexion – Supine PositionReproduced with permission from JF Sarwark, ed: Essentials of Musculoskeletal Care, ed 4. Rosemont, IL, American Academy of Orthopaedic Surgeons, 2010.