Shoulder Impingement
Anatomy
The shoulder joint complex consists of 4 separate joints, these joints act in a coordinated fashion to produce all arm functions. The shoulder joint in the complex is a ball and a shallow socket joint. It is formed from a ball on the top of your arm bone and a shallow socket, which is part of the shoulder blade. The scapula (shoulder blade) is very important for the shoulder to function well. It has to be firmly held onto the body/rib cage by muscles, which are known as ‘scapula stabilizers’. Shoulder joint is inherently unstable, because unlike the hip joint which has a deep socket, the shoulder joint has a relatively shallow socket. The stability of this joint is provided by a group of small muscles called the rotator cuff that works constantly to make sure the ball is always in the socket and thus prevents dislocation. Above the ball and socket joint is a ligament, which is attached to a bony prominence (‘acromion’) on your shoulder blade. This forms an arch; the area between the shoulder joint and the arch is known as the sub-acromial space. Rotator cuff muscles attach from the shoulder blade onto the top of the arm bone, passing through the sub-acromial space. One tendon (‘supraspinatus’) sits in the middle of the sub-acromial space. A small fluid lining (‘bursa’) cushions the tendon from the roof of the arch.
Impingement
The most common problems at the shoulder complex are either shoulder instability or shoulder impingement. Instability can range from subluxation where the ball of the shoulder joint moves momentarily out and then back into the socket to dislocation where the ball dislocated out completely.
Impingement simply means pinching of soft tissues (mainly cuff tendons) under the latter described sub-acromial space which in turns leads to inflammation of this soft tissue. The rotator cuff appears to be vulnerable to tendon damage or degeneration (wear and tear). This particularly
affects the supraspinatus tendon in the sub-acromial space. Once the tendon becomes affected, it swells, filling more of the space, which increases the chance of the tendon and bursa becoming pinched. This is known as ‘impingement’. Anything that narrows the space between the rotator cuff and the arch above will tend to pinch and irritate the cuff. Tears in the tendon can occur from sudden injuries such as falling, but more commonly they develop gradually, as a wear-and-tear effect on the tendon. This is partly age related, but may result from longstanding impingement. The tears can be partial or full thickness.
Other common injuries in the shoulder complex include ACJ strain, Labral tears and also pain can often be referred to the shoulder from neck and upper back.
Symptoms of shoulder impingement
The main complaint is one of pain, often felt on the outside of the upper arm and occasionally can be felt down till the elbow. A classic presentation is of a painful arc on movement when the arm is lifted out to the side and up to your ear. This corresponds with the narrowing of the sub-acromial space
Causes
The underlying causes of most shoulder injuries are poor muscular control of the scapula stabilizers and weakness in rotator cuff muscles of the shoulder. Shoulder impingement is the most common shoulder injury.
Diagnosis
At The Sherwood Clinic, patient will first have a full examination of the joint by one of our clinicians. The assessment will include checking the range of movement of each component of shoulder complex, checking how the complex moves as whole and also muscular control and strength using specific techniques. This will ensure the physiotherapist can give you correct diagnosis and explain the cause/causes of the injury.
Treatment
At Sherwood, our patient is considered to be an active part of the treatment process. Once the patient and the clinician are both in agreement with the diagnosis, a treatment plan is decided. Treatment will include a combination of “hands on techniques” to mobilize the joint and soft tissue and exercise therapy. If your injury was associated with a specific sport or activity or work requirement, we will work with you to improve the technique. Our physiotherapy clinicians specialize in sports injuries and will tailor sport specific therapies including individualized exercise plans.
At The Sherwood clinic we can also provide you guidance on your workstation and you can choose from other allied therapies such as Acupuncture, Electro-therapy and Ayurveda.
This article has been compiled by Mr Huzaifa Dahodwala MSc (Sports) MCSP