Shoulder anatomy and dislocation
The shoulder is the most mobile joint in our body. It consists of a ball known as the humeral head and a socket known as the glenoid. The high mobility of the shoulder requires a very shallow socket (glenoid). Around the socket there is a bumper (cartilage rim) called labrum which, together with a series of ligaments connecting the ball to the socket, prevent the ball slipping out of joint. These are called static stabilisers of the shoulder joint. On top of these structures there are four muscles called the rotator cuff connecting the scapula (shoulder blade) with the humerus (arm bone) and dynamically stabilising the shoulder when they contract. When the shoulder dislocates the traumatic force overcomes the blocking effect of the stabilisers and the labrum and ligaments can tear if the patient is young. Sometimes the rotator cuff muscles can tear if you are over 40 years of age. The shoulder can dislocate anteriorly (more common) or posteriorly. Shoulder dislocation is an emergency and requires urgent relocation under anaesthesia followed by a sling for 2 weeks and physiotherapy. A clinical examination by a specialised shoulder surgeon is recommended for active patients involved in sports activity.