Shoulder impingement is the condition of inflammation of the tendons of the shoulder joint. It is one of the most common causes of pain in the adult shoulder.
Traumatic injury to the shoulder or overuse of shoulder (throwing, weightlifting) may cause labral tear. In addition, ageing may weaken the labrum leading to injury.
The term arthritis literally means inflammation of a joint but is generally used to describe any condition in which there is damage to the cartilage. Damage of the cartilage in the shoulder joint causes shoulder arthritis.