Shoulder impingement syndrome is a common cause of shoulder pain. It happens when the bones of your shoulder pinch upon the soft-tissues in the area. Your shoulder girdle is made up of three bones, the arm bone, shoulder blade and the collar bone. Only the collar bone connects your shoulder to the rest of the skeleton.
Due to this setup, the shoulder has poor stability; but a large range of movement. It is for this reason that your shoulder needs the muscles around the joint to provide support. So imbalance or injury to these tissues, means your shoulder will become dysfunctional.
The top part of your shoulder blade, known as the acromion, forms a roof over the shoulder joint. The narrow gap between these is called the subacromial space. This space is narrowed even more when you lift your arm out to the side, many structures pass through this area. Therefore any condition that decreases this space, can cause an impingement syndrome. The term shoulder impingement really covers several conditions including:
- Biceps tendinitis
- Subacromial bursitis
- Rotator cuff tendinitis
- Rotator cuff tear
- Calcific tendinitis
- Repetitive strain injury (RSI)
The structures within the subacromial space
The rotator cuff are a group of muscles that attach the arm to the shoulder blade. This is made up of the supraspinatus, infraspinatus, teres minor and subscapularis. These muscles stabilise the shoulder joint, while controlling the orientation of the ball within its socket during movement.
The supraspinatus muscle and its tendon pass within the subacromial space (see picture below). The long-head of biceps tendon also passes through this space, acting to stabilise the front of the joint. The subacromial bursae is a fluid filled sac that sits under the acromion between underside of the bone and top side of supraspinatus tendon. Pain often originates from one of these structures.
You may not recall a specific incident that triggered the onset of symptoms, pain generally builds over time. Pain is worse with use and at night, commonly being felt around the outside of the shoulder and upper arm. The following features are often present:
- Pain when the arm is above head height;
- Discomfort when the arm is raised out to the side;
- Soreness when reaching behind the back;
- Night pain;
- Aching that radiates into the neck, back or arm.
Causes of shoulder impingement
There are many possible reasons why you may develop shoulder impingement. These factors may act alone or in combination..
- Age: as you age: your tendons, muscles and ligaments lose strength and their capacity for repair decreases.
- Poor posture: if your shoulders are rolling forward it’ll narrow the space available for the tendons and bursae. This can result in friction and tissue damage. Degeneration of these tissues will also happen due to this posture, as it interrupts normal blood circulation in the subacromial space.
- Overuse: repetitive use of your arms can result in fatigue and micro-trauma to the muscles and tendons. If the rate of tissue damage exceeds the rate of tissue repair, degeneration will occur.
- Muscle weakness: weakness and fatigue in your rotator cuff muscles is common. These muscles are put under continued stress. Very few people who participate in regular exercise (weight training, swimming) will perform specific rotator cuff strength and conditioning exercises, do you? Like any muscle group, once used, you should give them sufficient time to rest and recover. Muscle weakness and fatigue will increase the likelihood of tissue damage.
- Instability: are you particularly mobile i.e. a history of hyper-mobility, shoulder dislocations or been swimming since a young age? Laxity in your shoulders can predispose you to develop impingement syndrome. The problems result from the ball not staying properly centred in the socket.
- Stiffness: A fibrous joint capsule surrounds your shoulders ball and socket joint. Tightness in the back of your capsule can cause the ball to move abnormally upwards on the socket. This increases the friction and compression on your subacromial tissues.
Normally your medical history and physical examination is all that is needed to make a diagnosis. A referral for x-ray, ultrasound or MRI scan of your shoulder can be suggested if tests are inconclusive. These scans will help to rule out the possibility of rotator cuff tears, calcific tendinitis or arthritic changes.
Most shoulder impingement cases resolve with osteopathic treatment and avoidance of causative factors. Healing, especially of tendons is a slow process. It may take 4-12 weeks for symptoms to subside completely. Be aware that continued use and aggravation of your subacromial structures can result in full tendon rupture and chronic pain. You can give the Enfield Osteopath a call to arrange your consultation. Your osteopath will help with:
- Avoidance of aggravating and causative factors;
- Promoting healing by improving local circulation, movement and strength;
- Correcting of mechanical or postural issues that predisposed to the condition;
- Preventing of recurrence, by providing you with a home shoulder exercise program.
Here are the top 6 recommendations if your suffering with shoulder impingement syndrome:
- Stop or modify activities that cause you pain.
- Find your local osteopath or other musculoskeletal expert.
- Use ice therapy to reduce pain and swelling, this is particularly important during the early stages and after treatment and exercise sessions. Apply the ice pack for 10 minutes 2-4 times a day. Do not apply the ice directly on the skin.
- Non-steroid anti-inflammatory drugs i.e. Ibuprofen will help reduce inflammation and pain. They may only be effective during the early stages, when inflammation is more prevalent.
- Stop smoking, smoking effects the circulation to tendons, muscles and bones. Reduced circulation increases the risk of injury by slowing the rate of tissue repair.
- Take up some aerobic exercise, gentle exercise will improve overall cardiovascular health, allowing improved circulation and tissue repair.