| The shoulder joint
The shoulder joint is capable of a wider and more varied range of motion than any other joint in the human body and because of this flexibility, it also tends to be unstable and easily subject to injury.
The shoulder is composed of three bones: the clavicle (collarbone), the scapula (shoulder blade), and the humerus (upper arm bone). Two separate joints in the shoulder allow for full movement of the shoulder and arm. The glenohumeral joint, commonly called the shoulder joint, is a ball-and-socket type joint that helps move the shoulder forward and backward and allows the arm to rotate in a circular fashion or hinge out and up, away from the body. The "ball" is the top, rounded portion of the upper arm bone or humerus; the "socket," is the outer edge of the scapula into which the ball fits.
The bones of the shoulder are held in place by an intricate system of muscles, tendons, and ligaments.
There are four muscle tendons that connect to the shoulder that make up the rotator cuff. Together these four tendons stabilize the upper arm bone to the shoulder socket and allow the wide range of motion in the shoulder. Any swelling, inflammation, tearing, or bony changes around these tendons causes pain when a person tries to move the arm above the head, behind the back, or straight out in front. The supraspinatus, is most frequently involved in degenerative tears of the rotator cuff.
Tendons are tough cords or bands of dense white fibrous connective tissue that attach the shoulder muscles to bone which allows for movement of the shoulder. Ligaments attach shoulder bones to each other and provide stability.
The bursa is a fluid-filled sac that is located between the shoulder joint and the rotator cuff and allows the muscles to glide freely during movement. When rotator cuff tendons are injured or damaged, this bursa often becomes inflamed and painful as well.
The bones of the shoulder, in the joint, are covered with tissue called cartilage. The smooth surfaces of the cartilage allow for smooth, painless movement of the shoulder joint.
The rotator cuff
The rotator cuff is a group of muscles and tendons that form a cuff over the shoulder and is one of the most important structures in the shoulder. It is a combination of muscles and tendons surrounding the upper end of the arm bone (head of the humerus) in the shoulder joint. These muscles function to provide rotation and elevation of the arm as well as provide stability to the shoulder joint.
The rotator cuff is prone to tears and weakening which occurs most commonly in people who are over the age of 40. It may occur in younger patients, however, following acute trauma or repetitive overhead work or sports activity, such as throwers, tennis players, and swimmers.
Bursitis: There is a bursa (sac) between the rotator cuff and acromion that allows the muscles to glide freely when moving. When rotator cuff tendons are injured or damaged, this bursa often becomes inflamed and painful and is referred to as bursitis.
|A tear of the rotator cuff is suspected when the pain goes on in spite of a good rehabilitation program or when there is weakness in certain motions of the arm.
The best method of treatment for rotator cuff injury varies from person to person. The decision is based on the severity of symptoms and the person's functional requirements, as well as presence of other illnesses that may complicate treatment. The following are potential options for treatment:
- Exercise therapy: Your doctor
or a physical therapist will talk with you about specific exercises
designed to help heal your injury and improve the flexibility and
strength of your rotator cuff and shoulder muscles. Physical therapists often can provide the optimal rehabilitation necessary to restore function to the shoulder in the shortest period of time. Once the injury
heals with good range of motion restored, it's
important to continue exercising. Daily shoulder stretches and a
balanced shoulder-strengthening program can help prevent a
recurrence of the injury. Other treatments
- Corticosteroid injections by a health care professional often help relieve
inflammation and pain.
- Rest: Stop doing what caused the pain and try to avoid painful
movements. Limit heavy lifting or overhead activity for four to
seven days until your shoulder starts to feel better. Completely limiting
shoulder movement, however, for a long period of time, can lead
to frozen shoulder, a condition in which your shoulder becomes
so stiff you can barely move it.
- Application of ice and heat:
Ice applications help reduce inflammation and pain. Use a cold
pack for 20 minutes at a time. A pillow case containing
ice cubes applied directly to the
skin is an excellent method; it should be applied for only 10
minutes at a time. Apply ice every couple of hours the first day
or two. After about two or three days, when the pain and
inflammation have improved, hot packs or a heating pad may help
relax tightened and sore muscles. Limit heat applications to 20
- Pain relievers unless advised otherwise by your doctor. Over-the-counter (OTC)
nonsteroidal anti-inflammatory drugs (NSAIDs), such as aspirin,
ibuprofen (Advil, Motrin, others) or naproxen (Aleve), may help
reduce pain. Acetaminophen (Tylenol, others) may also help
relieve pain. Follow label directions and cautions. Stop taking
the drugs when the pain improves.
- Surgery may be necessary if there is a large tear of the rotator
cuff. Sometimes during this kind of surgery, doctors may also
remove a bone spur or calcium deposits.
Medline Plus Scroll
down to rotator cuff and follow the directions. You
will view a comprehensive tutorial complete with exercises.
This is a service of the Nat'l Library of Medicine and Nat'l
Institute of Health|
Virtual Body Tours
Click on "Interactive Human Atlas", select "Rotator Cuff"
from the pull-down menu, then select "Video"
Shoulder Problems from the National Institute of Arthritis and Musculoskeletal and Skin Diseases, Department of Health and Human Services
Rotator Cuff Injuries from the American Academy of Orthopedic Surgeons
|Written by N Thompson, MSN, ARNP and M Thompson, MD, Last updated December 2007
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