Shoulder Pain and Problems
What is the shoulder?
The shoulder is made up of several layers, including the following:
Bones. The collarbone (clavicle), the shoulder blade (scapula), and the upper arm
Joints. Facilitate movement, including the following:
Sternoclavicular joint (where the clavicle meets the sternum)
Acromioclavicular (AC) joint (where the clavicle meets the acromion)
Shoulder joint (glenohumeral joint). A ball-and-socket joint that facilitates forward,
circular, and backward movement of the shoulder.
Ligaments. A white, shiny, flexible band of fibrous tissue that binds joints together
and connects various bones and cartilage, including the following:
Joint capsule. A group of ligaments that connect the humerus to the socket of the
shoulder joint on the scapula to stabilize the shoulder and keep it from dislocating.
Ligaments that attach the clavicle to the acromion
Ligaments that connect the clavicle to the scapula by attaching to the coracoid process
Acromion. The roof (highest point) of the shoulder that is formed by a part of the
Tendons. The tough cords of tissue that connect muscles to bones. The rotator cuff
tendons are a group of tendons that connect the deepest layer of muscles to the humerus.
Muscles (to help support and rotate the shoulder in many directions)
Bursa. A closed space between 2 moving surfaces that has a small amount of lubricating
fluid inside; located between the rotator cuff muscle layer and the outer layer of
large, bulky muscles.
Rotator cuff. Composed of tendons, the rotator cuff (and associated muscles) holds
the ball of the glenohumeral joint at the top of the upper arm bone (humerus).
Shoulder pain may be localized in a specific area or may spread to areas around the
shoulder or down the arm.
What are some of the different types of shoulder problems?
Common shoulder problems include the following:
Dislocation. The shoulder joint is the most frequently dislocated major joint of the
body — often caused by a significant force that separates the shoulder joint's ball (the
top rounded portion of the upper arm bone, or humerus) away from the joint's socket
Separation. The AC joint becomes separated when the ligaments attached to the collarbone
(clavicle) are torn, or partially torn, away from the shoulder blade (scapula). Shoulder
separation may be caused by a sudden, forceful blow to the shoulder, or as a result
of a fall.
Bursitis. Bursitis often occurs when tendonitis and impingement syndrome cause inflammation
of the bursa sacs that protect the shoulder.
Impingement syndrome. Impingement syndrome is caused by the excessive squeezing or
rubbing of the rotator cuff and shoulder blade. The pain associated with the syndrome
is a result of an inflamed bursa (lubricating sac) over the rotator cuff, and/or inflammation
of the rotator cuff tendons, and/or calcium deposits in tendons due to wear and tear.
Shoulder impingement syndrome can lead to a torn rotator cuff.
Tendinosis. Tendinosis of the shoulder is caused when the rotator cuff and/or biceps
tendon become worn out and occasionally inflamed, usually as a result of being pinched
by surrounding structures. The injury may vary from mild inflammation to involvement
of most of the rotator cuff. When the rotator cuff tendon becomes inflamed and thickened,
it may become trapped under the acromion.
Rotator cuff tear. A rotator cuff tear involves 1 or more rotator cuff tendons becoming
inflamed from overuse, aging, a fall on an outstretched hand, or a collision.
Adhesive capsulitis (frozen shoulder). Frozen shoulder is a severely restrictive condition
frequently caused by injury that, in turn, leads to lack of use due to pain. Intermittent
periods of use may cause inflammation and adhesions to grow between the joint surfaces,
thus restricting motion. There is also a lack of synovial fluid to lubricate the gap
between the arm bone and socket that normally helps the shoulder joint to move. This
restricted space between the capsule and ball of the humerus distinguishes adhesive
capsulitis from the less complicated condition known as stiff shoulder.
Fracture. A fracture is a partial or total crack or break through a bone that usually
occurs due to a impact injury.
What causes shoulder problems?
Although the shoulder is the most movable joint in the body, it is also an unstable
joint because of its range-of-motion. Because the ball of the upper arm is larger
than the socket of the shoulder, it is susceptible to injury. The shoulder joint must
also be supported by soft tissues — muscles, tendons, and ligaments — which are also subject to injury, overuse, and under use.
Degenerative conditions and other diseases in the body may also contribute to shoulder
problems, or generate pain that travels along nerves to the shoulder.
How are shoulder problems diagnosed?
In addition to a complete medical history and physical examination (to determine range-of-motion,
location of pain, and level of joint instability/stability), diagnostic procedures
for shoulder problems may include the following:
X-ray. A diagnostic test that uses invisible electromagnetic energy beams to produce
images of internal tissues, bones, and organs onto film.
Magnetic resonance imaging (MRI). A diagnostic procedure that uses a combination of
large magnets, radiofrequencies, and a computer to produce detailed images of organs
and structures within the body; can often determine damage or disease in a surrounding
ligament or muscle.
Computed tomography scan (also called a CT or CAT scan). A diagnostic imaging procedure
that uses a combination of X-rays and computer technology to produce horizontal, or
axial, images (often called slices) of the body. A CT scan shows detailed images of
any part of the body, including the bones, muscles, fat, and organs. CT scans are
more detailed than general X-rays.
Electromyogram (EMG). A test to evaluate nerve and muscle function.
Ultrasound. A diagnostic technique that uses high-frequency sound waves to create
an image of the internal organs.
Laboratory tests (to determine if other problems may be the cause)
Arthroscopy. A minimally-invasive diagnostic and treatment procedure used for conditions
of a joint. This procedure uses a small, lighted, optic tube (arthroscope) that is
inserted into the joint through a small incision in the joint. Images of the inside
of the joint are projected onto a screen; used to evaluate any degenerative and/or
arthritic changes in the joint; to detect bone diseases and tumors; to determine the
cause of bone pain and inflammation.
Treatment of shoulder problems
Treatment may include: