What is the labrum of the shoulder?
The shoulder is a remarkably mobile joint, however, this flexibility comes with the cost of less stability. The glenohumeral joint, where the upper arm meets with the shoulder blade is a ball and socket type joint. The surface area of the ‘socket’ part of the joint (the glenoid fossa) is much smaller than the ball part of the joint (the head of the humerus). A fibro-cartilaginous ring called a labrum surrounds the edge of the glenoid fossa which acts to increase both the depth and width of the fossa.
This labrum provides increased stability and is also the attachment for a part of the biceps muscle via a long tendon. The labrum can provide flexibility and stability that a larger glenoid fossa might not be able to, however being a soft structure it is prone to tearing which can be problematic.
What causes the labrum to tear?
The most common way the labrum is torn is through a fall onto an outstretched arm or through repetitive overhead activities such as throwing or painting as the repeated stress on the labrum can cause it to weaken and tear.
Suspected labral tears can be diagnosed in a clinic by your physiotherapist through a series of tests, however, an MRI is required to fully confirm the presence of a labral tear. Labral tears are classified into different grades, which are determined by their location and severity. This grading is used as a guide to help determine the correct treatment.
What are the symptoms of a labral tear?
A labral tear is often associated with other injuries, such as rotator cuff tear, which can make the clinical picture a little confusing. Commonly there will be pain in the shoulder that is difficult to pinpoint and the pain will be aggravated by overhead and behind the back activities.
Severe labral tears can lead to instability and can also be related to dislocations of the shoulder.
How Can Physiotherapy Help?
The severity and grade of the labral tear will guide treatment. Smaller tears can be treated with physiotherapy that is aimed at increasing strength and control of the shoulder. Other tears may require surgical repair after which physiotherapy is an important part of treatment to rehabilitate the shoulder.