Tendonitis is the inflammation of the tendon that attaches to the bone. The tendon is the cord which attaches a muscle to the bone, and is made up of strong collagen and fibroblasts. It is surrounded by a perimysium which contains vessels that provide blood supply and nutrition. The tendon also gets nutrition from its attachment to the bone and surrounding tissues.
If the perimysium and, eventually the collagen and fibroblasts, have been exposed to a pathological repetitive low grade stress, inflammation will occur. Swelling occurs around the tendon and, if that tendon has been pinched, it can actually deform its shape and will become weaker at the point of pinching.
Now, how does this relate to your shoulder? First, we will take a look at the anatomy of the shoulder, specifically the rotator cuff. The rotator cuff is made up of 4 muscles which insert onto the humerus (the ball, of the ball & socket joint of the shoulder). These muscles grab the ball of the humerus much like fingers would grip a baseball, with each of them having a unique position so that as a group they help center the ball in the socket and aid in shoulder stability.
It is vital that the ball is seated properly into the socket during functional activities which include the shoulder. If it rides too high or forward, the tendons can get pinched between bones and possibly get injured.
In the case of the supraspinatus muscle (a muscle of the rotator cuff whose tendon most commonly gets injured), the tendon can get pinched as it moves through an already narrow corridor between the shelf of the acromion and the humerus (the subacromial space) during shoulder movements. The tendon then becomes irritated and the inflammation process begins. The patient may experience pain whenever that muscle is forced to be used or when the tendon gets pinched.
At Life’s Work Physical Therapy, treatment for rotator cuff tendonitis starts with a thorough evaluation and diagnosis of which structure(s) is affected. The therapist will also to rule out other causes of pain in that area such as shoulder bursae or the neck (cervical spine). Ice and rest can be used to help reduce inflammation. Physical therapy will include stretching and carefully dosed strengthening exercises for the affected muscle/tendon. Your physical therapist should always properly address posture and body mechanics to reduce the tendency towards faulty movement patterns that may be contributing to the problem. Take, for example, the common work situation people have which includes sitting and using the computer. The mouse arm tends to have a dropped shoulder, which repetitively reaches forward and out to the side, and places the shoulder in a jeopardized position. The scapula (shoulder blade) and thoracic spine are habitually placed in a non-functional position, and the ‘ball’ sits toward the front of the shoulder socket which inhibits the rotator cuff from properly working to stabilize the shoulder. Without correcting this postural habit, it is unlikely that the patient’s problem will fully resolve, no matter what strengthening/stretching exercises are prescribed.
Tendonitis is a diagnosis that will take at least 10-12 weeks to fully decrease the inflammation and promote the proper tendon healing once treatment is initiated. The pain should begin to reduce when you cease the aggravating movements and begin improving the shoulder mobility. Remodeling of the tendon will continue to occur over the following 2-3 months, which is why specific strengthening and loading of the tendon is important to have it heal more efficiently. Shoulder tendinitis is a very treatable condition, with high short- and long-term success when addressed appropriately. If you are experiencing shoulder symptoms which affect your functional activities, contact your physical therapist today to set up an evaluation to determine why you are experiencing pain and have them help you get on a proper path towards recovery.