Shoulder Problems
This fact sheet first
answers general questions about the shoulder and shoulder problems.
It then answers questions about specific shoulder problems (dislocation,
separation, tendinitis, bursitis, impingement syndrome, torn
rotator cuff, frozen shoulder, and fracture) as well as diseases
that can cause shoulder pain (arthritis, myofascial pain, reflex
sympathetic dystrophy, and thoracic outlet syndrome).
How
Common Are Shoulder Problems?
According to the
American Academy of Orthopaedic Surgeons, about 4 million people
in the U.S. seek medical care each year for shoulder sprain,
strain, dislocation, or other problems. Each year, shoulder
problems account for about 1.5 million visits to orthopaedic
surgeons—doctors who treat disorders of the bones, muscles,
and related structures.
What
Are the Structures of the Shoulder and How Does the Shoulder
Function?
The shoulder joint
is composed of three bones: the clavicle (collarbone), the scapula
(shoulder blade), and the humerus (upper arm bone) (see diagram).
Two joints facilitate shoulder movement. The acromioclavicular
(AC) joint is located between the acromion (part of the scapula
that forms the highest point of the shoulder) and the clavicle.
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,” or glenoid, is a dish-shaped part of the outer edge
of the scapula into which the ball fits.) The capsule is a soft
tissue envelope that encircles the glenohumeral joint. It is
lined by a thin, smooth synovial membrane.
The bones of the shoulder
are held in place by muscles, tendons, and ligaments. Tendons are tough
cords of tissue that attach the shoulder muscles to bone and assist
the muscles in moving the shoulder. Ligaments attach shoulder bones
to each other, providing stability. For example, the front of the joint
capsule is anchored by three glenohumeral ligaments.
Structures
of the Shoulder
The rotator cuff is a structure
composed of tendons that, with associated muscles, holds the ball at
the top of the humerus in the glenoid socket and provides mobility and
strength to the shoulder joint. Two filmy sac-like structures called
bursae permit smooth gliding between bone, muscle, and tendon. They
cushion and protect the rotator cuff from the bony arch of the acromion.
What
Are the Origin and Causes of Shoulder Problems?
The shoulder is the most
movable joint in the body. However, it is an unstable joint because
of the range of motion allowed. It is easily subject to injury because
the ball of the upper arm is larger than the shoulder socket that holds
it. To remain stable, the shoulder must be anchored by its muscles,
tendons, and ligaments. Some shoulder problems arise from the disruption
of these soft tissues as a result of injury or from overuse or underuse
of the shoulder. Other problems arise from a degenerative process in
which tissues break down and no longer function well.
Shoulder pain may be localized
or may be referred to areas around the shoulder or down the arm. Disease
within the body (such as gallbladder, liver, or heart disease, or disease
of the cervical spine of the neck) also may generate pain that travels
along nerves to the shoulder.
How
Are Shoulder Problems Diagnosed?
- Following are some of
the ways doctors diagnose shoulder problems:
- Medical history (the patient
tells the doctor about an injury or other condition that might be
causing the pain).
- Physical examination to
feel for injury and discover the limits of movement, location of pain,
and extent of joint instability.
- Tests to confirm the diagnosis
of certain conditions. Some of these tests include:
- x ray
- arthrogram—Diagnostic
record that can be seen on an x ray after injection of a contrast
fluid into the shoulder joint to outline structures such as the rotator
cuff. In disease or injury, this contrast fluid may either leak into
an area where it does not belong, indicating a tear or opening, or
be blocked from entering an area where there normally is an opening.
- MRI (magnetic resonance
imaging)—A non-invasive procedure in which a machine produces a series
of cross-sectional images of the shoulder.
Other diagnostic tests, such
as injection of an anesthetic into and around the shoulder joint, are
discussed in specific sections of this fact sheet.
Index to
Shoulder Injuries and Problems
Where Can
People Get Additional Information About Shoulder Problems?
- American
Academy of Orthopaedic Surgeons
P.O. Box 2058
Des Plaines, IL 60017
847/823-7186
800/346-2267
Fax: 847/823-8026
E-mail: julitz@mac.aaos.org
World Wide Web address: http://www.aaos.org
The American Academy of Orthopaedic Surgeons (AAOS) is a not-for-profit
organization that provides education programs for orthopaedic surgeons,
allied health professionals, and the public and is an advocate for
improved patient care. The AAOS has the following educational brochures
on the shoulder: Shoulder Pain,” Arthroscopy,” and Joint Replacement.”
Single copies are free upon submission of a business-size, stamped,
self-addressed envelope.
- American
Physical Therapy Association
1111 North Fairfax Street
Alexandria, VA 22314-1488
703/684-2782
800/999-2782 x3395
World Wide Web address: http://www.apta.org
The American Physical Therapy Association (APTA) is a national professional
organization representing physical therapists, allied personnel, and
students. Its objectives are to improve research, public understanding,
and education in the physical therapies. APTA provides a free brochure
titled Taking Care of Your Shoulder: A Physical Therapist's Perspective”
upon submission of a business-size, stamped, self-addressed envelope.
- Arthritis
Foundation
1330 West Peachtree Street
Atlanta, GA 30309
404/872-7100
800/283-7800 or call your local chapter (listed in the telephone directory)
World Wide Web address: http://www.arthritis.org
This is the major voluntary organization devoted to arthritis. The
Foundation publishes pamphlets on arthritis, such as Arthritis Answers,”
that may be obtained by calling the toll-free telephone number. The
Foundation also can provide physician and clinic referrals. Local
chapters also provide information and organize exercise programs for
people who have arthritis.
- American
College of Rheumatology/Association of Rheumatology Health Professionals
60 Executive Park South, Suite 150
Atlanta, GA 30329
404/633-3777
Fax: 404/633-1870
World Wide Web address: http://www.rheumatology.org
This national professional organization can provide referrals to rheumatologists
and allied health specialists, such as physical therapists. One-page
fact sheets are also available on various forms of arthritis. Lists
of specialists by geographic area and fact sheets are also available
on ACR's web site.
*Brand names
included in this fact sheet are provided as examples only, and their
inclusion does not mean that these products are endorsed by the National
Institutes of Health or any other Government agency. Also, if a particular
brand name is not mentioned, this does not mean or imply that the product
is unsatisfactory.
Acknowledgments
The NIAMS gratefully acknowledges
the assistance of Frank A. Pettrone, M.D., of Arlington, Virginia; Thomas
J. Neviaser, M.D., of Fairfax, Virginia; and James Panagis, M.D., M.P.H.,
of the National Institutes of Health, in the preparation and review
of this fact sheet.
The
National Arthritis and Musculoskeletal and Skin Diseases Information
Clearinghouse (NAMSIC) is a public service sponsored by the NIAMS that
provides health information and information sources. The NIAMS, a part
of the National Institutes of Health (NIH), leads the Federal medical
research effort in arthritis and musculoskeletal and skin diseases.
The NIAMS sponsors research and research training throughout the United
States as well as on the NIH campus in Bethesda, MD, and disseminates
health and research information.
JW
8/97
Office of Scientific and Health Communications
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