What is infraspinatus tendonitis?
Infraspinatus tendinitis is a strain caused to the infraspinatus tendon. This muscle tendon unit is responsible for the lateral rotation of the shoulder.
This tendon attaches muscle to bone and is the focus for the pull of the muscle. On damage , the muscle pulls part of the tendon away from the bone and the attachment point becomes frayed and sore. Because of its poor mechanical advantage , the infraspinatus is a relatively weak muscle in most people.
Tendons grow slowly so it's place is the taken by scar tissue, which do not have as good pulling power as the tendon. The scar tissue sticks to the surrounding tissues and causes adhesion. These damage the surrounding musculature and restricts circulation , which is a vital part of healing.
As a result the tendon is more likely to injure again as because of poor quality of the mend. As the blood supply to the tendons is poor , the speed of recovery is also slow.
This tendon strain occurs in people who play racquet sports and typically comes on slowly. The injury interferes with sleep, sports and even everyday movements. It can be a very painful and tenacious injury.