Dislocated Shoulder (cont.)

Dislocations hurt. When the humerus is pulled out of the socket, cartilage, muscle, and other tissues are stretched and torn. Shoulder dislocations present with significant pain, and the patient will often refuse to move the arm in any direction. The muscles that surround the shoulder joint tend to go into spasm, making any movements very painful. Usually, with anterior dislocations, the arm is held slightly away from the body, and the patient tries to relieve the pain by supporting the weight of the injured arm with the other hand. Often, the shoulder appears squared off since the humeral head has been moved out its normal place in the glenoid fossa. Sometimes, it may be seen or felt as a bulge in front of the shoulder joint.

As with other bony injuries, the pain may provoke systemic symptoms of nausea and vomiting, sweating, lightheadedness, and weakness. These occur because of the stimulation of the vagus nerve, which blocks the adrenaline response in the body. Occasionally, this may cause the patient to faint or pass out (vasovagal syncope).

When a patient presents with a shoulder dislocation, pain control and joint relocation are primary considerations. However, it is still important for the health-care provider to take a careful history to understand the mechanism of injury and the circumstances surrounding it. In addition, information about medications, allergies, time of the last meal, and past medical history may be asked to prepare for a potential anesthetic administration to help relocate, or reduce, the shoulder dislocation. It will also be important to know if this is the first shoulder dislocation or whether the joint has been previously injured.

Pain and muscle spasm accompany dislocated joints, and a shoulder dislocation is no different. When the joint is disrupted, the muscles surrounding it are stretched and go into spasm. The patient will experience significant pain and will often resist the smallest movement of any part of the arm.

Physical examination of the shoulder will begin with inspection to look for "squaring off," or a loss of the normal rounded appearance of the shoulder caused by the deltoid muscle. In thinner patients, the humeral head may be palpated or felt in front of the joint.

The health-care provider may examine the blood and nerve supply to the arm since injuries may occur to arteries and nerves when the shoulder is dislocated. The brachial plexus, the axillary artery, and axillary nerve are located in the armpit and are relatively unprotected. Complications of shoulder dislocation can include artery and nerve damage.

Plain X-rays may be taken to confirm the diagnosis of shoulder dislocation and to make certain there are no broken bones associated with the dislocation. Two common fractures are the Hill-Sachs deformity, a compression fracture of the humeral head, and a Bankart lesion, a chip fracture of the glenoid fossa. While these may be present, they do not hinder the relocation of the shoulder. Other fractures of the humerus and scapula may make shoulder reduction more difficult.

Since the body is 3-D and X-rays are 2-D, at least two X-rays are taken to be able to accurately assess where the humeral head is located in relationship to the glenoid. Extra X-ray views also better assess the bones, looking for fracture.

In certain circumstances, (often on the athletic field) if a health-care provider is present at the time of injury, an attempt may be made to reduce or relocate the shoulder immediately without X-rays being taken. Using manipulation described below, before the muscles have a chance to go into spasm, it is possible to relocate the shoulder. Imaging of the injured shoulder (X-ray or MRI) would then be considered at a later time.

Source: MedicineNet.com
http://www.medicinenet.com/dislocated_shoulder/article.htm