It also has the least structural support and so the muscles and tendons around it have to work very hard to keep the joint in an optimal position. Common injuries of the shoulder are therefore damage or irritation to these muscles or their tendons as they join into the bone or damage to the capsule of the joint due to trauma or degeneration.
This occurs when the tendons of the shoulder become inflamed and then bump into the roof of the shoulder joint the acromium. This creates wear and tear of the tendon. This can also be caused by a bony spur growing in this space which also can irriatate the joint and make lifting the arm painful
This can occur from trauma such as a throwing injury or from general wear and tear to the tendon. If damage is severe this may need surgical intervention but will often recover with suitable physiotherapy.
This is an injury to the tissue that helps to protect the shoulder joint. This is a very poor area for circulation and so these tears typically will not heal without surgery. There are exercises and soft tissue work however which can be done to help relax the muscles and strengthen the joint.