shoulder anatomy
BASIC SHOULDER ANATOMY
The shoulder joint is made of up two primary bones, the humerus and the scapula also known as the shoulder blade, These two bones make up what is called the gleno-humeral joint. The humerous has a smooth covering called articular cartilage that allows the bone to fit into the glenoid of the scapula; this allows the joint to move smoothly. The scapula has to major sites of muscle attachment that are called the acromion, and the coracoid process.
shoulder anatomy
The “ball and socket” joint is a very mobile joint, and not a very stable joint. The shoulder joint has a ring of cartilage called a labrum that forms a cup for the end of the arm bone (humerus) to move within. The labrum circles the shallow shoulder socket (the glenoid) to make the socket 50% deeper. This cuff of cartilage makes the shoulder joint much more stable, and allows for a very wide range of movements.
The labrum it serves as an attachment site for several ligaments and is part of the joint capsule, covering the shoulder joint, that is comprised of the ligaments that connect the bones of the shoulder, and tendons join the bones to surrounding muscles. The biceps tendon attaches the biceps muscle to the shoulder and helps to stabilize the joint.
Four small muscles originate on the scapula and pass around the shoulder where their tendons fuse together to form the rotator cuff. (Supraspinatus, Infraspinatus, Teres minor, and supscapularis muscles) The rotator cuff is a dynamic stabilizer of the shoulder joint and helps to depress the humeral head.
The numerous structures in the shoulder, along with the muscles of your upper body, work together to manage the stress your shoulder receives as you extend, flex, lift, reach and throw.
shoulder anatomy
ROTATOR CUFF PATHOLOGIES
INFORMATION
As shown above, the rotator cuff is the name for the muscles/tendons that surround the shoulder joint. The rotator cuff is important in allowing the shoulder to function through a wide range of motions. In part due to the rotator cuff, the shoulder joint can move and turn through a wider range than any other joint in the body. This motion of the shoulder joint allows us to perform an amazing variety of tasks with our arms. The rotator cuff is part of this mechanism that, when healthy functions very well, but when injured can be a difficult and frustrating problem.
shoulder anatomy
ROTATOR CUFF TEARS AND INJURY
In rotator cuff injuries, the most common complaint is aching located in the top and front of the shoulder, or on the outer side of the upper arm (deltoid area). The pain is usually increased when the arm is lifted to the overhead position. Frequently, the pain seems to be worse at night, and often interrupts sleep.
shoulder anatomy
A rotator cuff tear occurs when there is an injury to one of the rotator cuff tendons. Rotator cuff tears occur in many shapes and sizes, but can be thought of as a hole in one of the tendons around the shoulder joint. Like most orthopedic conditions, the most common mechanisms of a rotator cuff tear are separated into ‘repetitive use’ and ‘traumatic injuries.’ Supraspinatus is the most commonly involved tendon in a rotator cuff injury
shoulder anatomy
Depending on the severity of the injury, there may also be weakness in the arm and, with some complete rotator cuff tears, the arm cannot be lifted in the forward or outward direction at all. Rotator cuff tears are a common cause of shoulder pain and dysfunction, accounting for approximately 50% of significant shoulder injuries, research shows that 25% of tears are symptomatic to the individual.
shoulder anatomy
SURGICAL TREATMENT
When the tendon of the rotator cuff has a complete tear, the tendon often must be repaired using surgical techniques. The choice of surgery, of course, depends on the severity of the symptoms, the health of the patient, and the functional requirements for that shoulder. In young working individuals, repair of the tendon is most often suggested. In some older individuals who do not require significant overhead lifting ability, surgical repair may not be as important, and the patient will be treated conservatively with physical therapy (see PHYSICAL THERAPY below). If chronic pain and disability are present at any age, consideration for repair of the rotator cuff should be given. In a minor operation for impingement, the shoulder is placed in a simple sling. If a full thickness tear of the rotator cuff was present and repaired, then the shoulder will be supported by an postoperative brace.
PHYSICAL THERAPY & POST OPERATIVE CARE
The brace is very helpful because it places the arm in a position that promotes better blood circulation and relieves stress on the repaired rotator cuff tissues. Physical therapy is prescribed after surgery with a program that will allow a period of time for healing of the soft tissues followed by time to regain range of motion and then strengthen the shoulder muscles, but particularly the rotator cuff. If the rotator cuff tendon has been completely torn, it may take six months or more before the atrophied muscles can resume their function and the range of motion of the arm is restored. Frequently, pain relief is much quicker and return to daily activities is often possible by two to three months. Consistent treatment by a physical therapist is most beneficial due to specific post surgical protocols that will help the patient to return to full function at the appropriate time without re-injury to the surgical correction. Again, every case is unique, as the injury becomes more severe, such as with a large bone spur and fragmentation of the tendon, then a perfect result cannot be expected. Since it is necessary to trim back the unhealthy tendon before reattaching it to the bone, a decreased range of motion of the shoulder will often result. Despite this, pain relief and return of strength are usually well worth the minor decreased mobility. The final outcome often depends on the willingness and ability of an individual patient to work on their postoperative physical therapy program.
FROZEN SHOULDER
INFORMATION & INJURY
Frozen shoulder, or adhesive capsulitis, is a condition that causes restriction of motion in the shoulder joint. Pain due to frozen shoulder is usually dull or aching. It can be worsened with attempted motion. The pain is usually located over the outer shoulder area and sometimes the upper arm. The affected individual cannot move the shoulder normally. Motion is also limited when someone else attempts to move the shoulder for the patient.
The cause of a frozen shoulder is not well understood, but it often occurs for no known reason. Frozen shoulder causes the capsule surrounding the shoulder joint to contract and form scar tissue or adhesions, therefore preventing active motion and cause movement to become painful.
Some risk factors for developing a frozen shoulder include:
Age & Gender
Frozen shoulder most commonly affects patients between the ages of 40 to 60 years old, and it is twice as common in women than in men.
Endocrine Disorders
Patients with diabetes or thyroid problems are at particular risk for developing a frozen shoulder.
Shoulder Trauma or Surgery
Patients who sustain a shoulder injury, or undergo surgery on the shoulder can develop a frozen shoulder joint. When injury or surgery is followed by prolonged joint immobilization, the risk of developing a frozen shoulder is highest.
Other Systemic Conditions
Several systemic conditions such as heart disease and Parkinson’s disease have also been associated with an increased risk for developing a frozen shoulder.
PHYSICAL THERAPY TREATMENT
The normal course of a frozen shoulder as having three stages:
Stage one: In the “freezing” stage, the patient develops a slow onset of pain. As the pain worsens, the shoulder loses motion. This stage may last from six weeks to nine months.
Stage two: The “frozen” stage is marked by a slow improvement in pain, but the stiffness remains. This stage generally lasts four months to nine months.
Stage three: The final stage is the “thawing,” during which shoulder motion slowly returns toward normal. This generally lasts five months to 26 months.
Physical therapy is used to restore motion. This may be under the direct supervision of a physical therapist and a home program. Therapy includes stretching or range-of-motion exercises for the shoulder. Sometimes, heat is used to help decrease pain. Examples of some of the exercises that might be recommended can be seen in the following figures.
More than 90 percent of patients improve with these relatively simple treatments. Usually, the pain resolves and motion improves. However, in some cases, even after several years the motion does not return completely and a small amount of stiffness remains. If conservative treatment is not successful, surgical intervention is aimed at stretching or releasing the contracted joint capsule of the shoulder. The most common methods include manipulation under anesthesia and shoulder arthroscopy.