What is shoulder instability?
The shoulder joint is the most mobile joint in the body and allows the arm to move in many directions. This ability to move makes the joint inherently unstable and also makes the shoulder the most often dislocated joint in the body.
The head of the humerus (upper arm bone) sits in the glenoid fossa, an extension of the scapula, or shoulder blade. Because the glenoid fossa (fossa = shallow depression) is so shallow, other structures within and surrounding the shoulder joint are needed to maintain its stability. Within the joint, the labrum (a fibrous ring of cartilage) extends from the glenoid fossa and provides a deeper receptacle for the humeral head.
The capsule tissue that surrounds the joint also helps maintain stability. The rotator cuff muscles and the tendons that move the shoulder provide a significant amount of protection for the shoulder joint.
Dislocations of the shoulder occur when the head of the humerus is forcibly removed from its socket in the glenoid fossa. The shoulder can be dislocated in many different directions, and a dislocated shoulder is described by the location where the humeral head ends up after it has been dislocated.
Ninety percent or more of shoulder dislocations are anterior dislocations, meaning that the humeral head has been moved to a position in front of the joint. Posterior dislocations are those in which the humeral head has moved backward toward the shoulder blade.
Symptoms of shoulder instability
Due to the altered biomechanics of an unstable shoulder, it is possible for shoulder instability to present in a variety of ways. It is not uncommon for there to be a constant dull ache around the shoulder due to the overuse of the rotator cuff muscle group. The shoulder will likely be painful on extreme ranges of movement. There may be a noticeable ‘clicking’ of the joint with certain movements.
Resulting dislocations are very painful. 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, light headedness, 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 ass out (vasovagal syncope).
Suggestions for treating shoulder instability
Treatment options depend on the severity and nature of the instability ie which specific tissues in the shoulder joint are deficient. Remedial massage therapy, osteopathy, physiotherapy and myotherapy will help reduce the presence of painful trigger points around the joint. In addition your osteopath will tailor a program of exercises to restore the muscular component of the instability.
In severe cases, reconstructive surgery is often required to restore the integrity to the deep ligaments of the shoulder joint.
Your practitioner at Premier Health Partners is expertly trained to determine the most appropriate form of treatment that is tailored specifically for you.
Contact us now for immediate advice regarding shoulder instability.