The shoulder joint is arguably the most interesting joint of the body, both in function and anatomy. It has the most movement of any of our joints. Lift your arm up, move it around, backwards and forwards. No other joint moves as much.
It is allowed to do this because of its anatomy. It is a ball and socket joint but the socket is shallow so the ball moves with great freedom. Ligaments/Joint capsule provide some stability but most important is the rotator cuff.
These are 4 muscles that wrap around the shoulder joint much like a cuff does. They contract when the shoulder moves thus providing dynamic support.
But with all this movement comes a price. The shoulder is easily injured and most commonly it is the rotator cuff that is injured as it works constantly to stabilise the joint. There are tears with lifting or falls and also rotator cuff tendonitis with overuse. Sometimes both conditions co-exist. Young or old people may get these injuries. Supraspinatus is the most commonly injured cuff tendon. Bursitis of the shoulder is frequently associated with these injuries because of friction between cuff tendons and bone which can increase pain.
Shoulder joint dislocations and subluxation (partial dislocations) occur mainly in the young. No other joint in the body dislocates as often and it is due to the anatomy of the shoulder.Anterior shoulder dislocations are more common and a person will feel something pop out usually with a great deal of pain. Significant trauma is required for this to happen usually on the sporting field. It is important for the shoulder to be reduced (popped back in) as soon as possible and a sling is then worn. Starting Physiotherapy as soon as possible is very important for shoulder injuries.
At the tip of your shoulder is the acromioclavicular (AC) joint. AC joint injuries are often described as shoulder injuries. This joint occurs between your collarbone (clavicle) and your shoulder blade (scapula).
This joint is very different to the shoulder joint in that it has very little movement courtesy of the joint capsule and strong ligaments that bind the joint and no muscles that move the joint.
The AC joint is important in allowing the shoulder blade to move and rotate on the collar bone when the arm is elevated. One third of your arm elevation occurs because the shoulder blade rotates upwards as you lift your arm.
A fall on your shoulder can sprain or tear the ligaments that stabilise the AC joint. This injury can be minor or significant depending on the degree of damage. With more severe injuries the clavicle lifts up providing a step deformity. Only very severe injuries require surgery as conservative treatment is very successful.
Physiotherapy treatment of your shoulder injury will depend on which injury you have sustained. Sometimes scans are needed to determine the severity of injury. The three mentioned are the most common sporting injuries.
The principles are to minimise inflammation in the early stages, protect the injured structures and encourage healing. Later on to restore full movement, strength and return to your chosen sport.
Electrotherapy, ice, shoulder slings, tape, and exercises are started straight away and as improvement occurs, joint stretching, soft tissue massage and progression of strengthening exercises. An explanation of the injury is given with an expected return to sport or work if appropriate.
Next time you play tennis, go for a swim or swing a golf club you might marvel at the design of your shoulder.