Shoulder Anatomy | Shoulder Description | Shoulder Pain | Shoulder Treatments | Shoulder Replacement | Shoulder Surgery
The shoulder is the most flexible large joint in the body and powers all arm movement, yet the shoulder is especially prone to injury. Common shoulder injuries include rotator cuff tears, labral tears, impingement syndrome, shoulder dislocation and frozen shoulder. Tendonitis, bursitis and arthritis are also frequent reasons for seeing a shoulder specialist. If you are experiencing shoulder pain in your arms or upper back, it should not be ignored, since it can be an indicator of a larger problem. Agility Orthopaedics offers a full range of treatment options for shoulder pain and injuries.
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The shoulder is one of the most sophisticated and complicated joints of the body. The shoulder joint is a ball and socket that connects the upper arm to the body. The two main bones of the shoulder are the humerus and the scapula (shoulder blade). Conditions that can affect the bones include arthritis, shoulder dislocation or fracture. The shoulder joint is held in place by ligaments and muscles, including the rotator cuff group of muscles, which can be often associated with shoulder problems.
Published with permission from Tornier.
The Anatomy of a Shoulder
It has the greatest range of motion of any joint in the body. It is made up of three bones:
- the collarbone or clavicle
- the shoulder blade or scapula
- and the upper arm bone or humerus
There are also two important joints that allow for movement:
- The acromioclavicular joint connects the upper part of the shoulder blade (the acromion) to the collarbone.
- The glenohumeral joint, also known as the shoulder joint, is a ball-and-socket joint that connects the upper arm to the shoulder blade. This joint allows free movement of the arm so that it can rotate in a circular fashion.
The shoulder is the most moveable joint in the body, however it is also one of the most unstable joints because the ball (the humerus) is larger than the socket (the glenoid) that holds it. The bones of the shoulder are held in place by muscles, tendons, and ligaments, which helps to maintain stability.
The rotator cuff is made up of four muscles and their tendons, which act to hold the upper arm (humerus) to the socket of the shoulder. These four muscles are related and work together. The rotator cuff helps to provide mobility and strength to the shoulder joint. The bursae, two sac-like structures, allow smooth gliding between the bone, muscle, and tendon. The bursae also cushions and protects the rotator-cuff structures from the upper part of the scapula.
The main causes of shoulder pain
AAOS reports about 23,000 people have shoulder replacement surgery each year. This compares to more that 700,000 Americans a year who have knee and hip replacement surgery*. Many shoulder issues are a result of injury to the soft tissues of the shoulder, overuse or underuse of the shoulder or even because of damage to the tissues.
Shoulder problems usually result in pain, which may be felt in the joint or in areas around the shoulder or down the arm. Damage to the shoulder joint may result in instability of the joint, and pain is often felt when raising the arm or when soft tissues are trapped between the bones, causing shoulder impingement. Shoulder impingement is fairly common in sports activities that involve repetitive overhead arm motions, such as baseball or tennis.
Signs of a shoulder injury:
- Your shoulder feels stiff and doesn’t allow full normal movement
- Your shoulder doesn’t have the strength to perform your daily activities
- Your shoulder feels as if it’s slipping out of place or you have a “popping” or a feeling that your arm is sliding out of the shoulder socket
Arthritis is another cause of shoulder pain. The most common type of arthritis is osteoarthritis (OA). It also sometimes known as degenerative arthritis because it is a “wearing out” condition from the breakdown of cartilage in the joints. OA is mostly the result of a shoulder injury, but can occur without a shoulder injury as well. However, it is rare for OA to occur without an injury since the shoulder is not a weight-bearing joint such as the knee or hip. Shoulder OA commonly develops many years following a shoulder injury, such as a dislocation, that has led to joint instability and damage.
*AAOS.org — January 2006.
Shoulder Pain Treatment Options
An orthopedic evaluation of your shoulder will allow your doctor to diagnosis your shoulder and suggest treatment options that may include:
- Physical therapy
- Shoulder joint fluid supplements (an injection that provide temporary pain relief)
- Total shoulder joint replacement
A shoulder replacement may be recommended when joint pain and stiffness become severe enough to affect your daily life, comfort and when that pain is not relieved by other treatment plans.
Shoulder Replacement Surgery
Shoulder replacement is not as common than knee or hip replacement. However, shoulder replacement typically offers all the same benefits as other joint replacements — including pain relief and the restoration of more normal joint movement caused from an arthritic condition or injured shoulder.
The main goal in shoulder replacement is to restore the movement in the shoulder, since it is the mechanism that allows your arm to rotate in every direction. Severe shoulder pain and reduced shoulder movement, inhibits many daily activities. For this reason, you may consider shoulder replacement surgery.
In shoulder replacement surgery, the artificial shoulder joint can have either two or three parts, depending on the type of surgery required.
- The humeral component (metal)
- The humeral head component (metal)
- The glenoid component (plastic) replaces the surface of the socket
Two types of shoulder replacement procedures:
- Partial shoulder replacement is performed when the glenoid socket is intact and does not need to be replaced. In this procedure, the humeral component is implanted and the humeral head is replaced.
- Total shoulder replacement is performed when the glenoid socket is damaged and needs to be replaced. All three shoulder joint components are used in this procedure.
What’s involved in shoulder surgery?
During shoulder replacement surgery, parts of the shoulder joint are removed and replaced. A plastic or metal device called a prosthesis or artificial joint is implanted into the shoulder joint. Depending on the type of surgery, the artificial shoulder joint can have two or three parts.
- The humeral component (metal) is implanted in the humerus or upper arm bone.
- The humeral head component (metal) replaces the humeral head at the top of the humerus.
- The glenoid component (plastic) replaces the surface of the glenoid socket, or shoulder socket.