The shoulder is a ball and socket joint and needs to allow for a very large range of movement which leaves the joint very susceptible to injury as it is much less stable than, for example, the hip joint.
The main causes of shoulder pain originate from the rotator cuff, the glenoid labrum (a tissue ring which surrounds the joint), joint instability and problems with the AC (acromioclavicular) Joint. Shoulder injuries occur acutely following sudden impact, strain to the surrounding muscles or excessive twisting of the joint.
Some common injuries to the shoulder include:
Rotator cuff tear
This is one of the most common causes of shoulder pain and it occurs when there is sudden or excessive pressure put through the muscle causing it to tear. Symptoms include a sudden pain in the shoulder, which can range from mild to severe and can often worsen over time with overhead and other shoulder movements.
The most common mechanism of injury usually involves the arm being rotated outwards and backwards, which is why it is common in contact sports. Severe shoulder pain, rapid swelling and inability to move the arm are symptoms and immediate medical attention is required.
Deltoid muscle strain
The deltoid is the muscle which sits on top of the shoulder and a muscle strain occur when there is a tear to the muscle belly, which usually causes pain at the front, side or back of the shoulder. This injury is less common than a rotator cuff injury however it is still fairly common in contact sports.
Biceps tendon inflammation
Occurs when there is overuse of the biceps muscle which causes inflammation at the tendon site. Symptoms include gradual onset of pain at the front of the shoulder, tenderness when pressing in at the front of the shoulder and lifting the arm out forwards against resistance or over head movements with aggravate them
Also known as Adhesive Capsulitis. The shoulder is lined with a capsule which contains a lubricant which ensures that the joint moves smoothly however sometimes this capsule can become inflamed and thickened. The symptoms tend to gradually worsen over time, causing pain and stiffness and in severe cases it can completely prevent shoulder movement. There are three phases to a frozen shoulder; a freezing phase where the joint tightens up, a stiff phase where the pain is less but also range of movement is very limited and a thawing phase where normal function is regained.
Biceps tendon rupture
Occurs when there is sudden forceful contraction of the biceps muscle which causes the tendon to rupture. Symptoms include a sudden sharp pain at the front of the upper arm, as well as pain and swelling at the front of the shoulder or upper arm. Contracting the biceps muscle against resistance may be painful.
Rotator cuff tendinopathy
The rotator cuff is made up of four muscles- Supraspinatus, Infraspinatus, Subscapularis and Teres Minor. Tendonitis or Tendinosis (commonly referred to as tendionpathy) is a degenerative condition of any of the four rotator cuff tendons and symptoms often have a gradual onset with pain in the shoulder when rotating the arm, especially against resistance being the most common, along with a dull ache around the shoulder.
This occurs when one of the rotator cuff tendons gets trapped in the gap known as the subacromial space. The tendon repeatedly rubs against the bone causing inflammation, especially when raising your arm above your head as the space naturally gets smaller. Symptoms will come on gradually over a period of time and there may be pain at the front, back or side of the shoulder, which worsens during overhead movements such as throwing or in racket sports.