Rugby Injuries: Shoulder impingement syndrome
I’m gonna discuss this problem in a simple ‘all you need to know’ style. The shoulder is essentially a relatively loose joint that lacks the stability that many of the other large joints benefit from. This is because the bony socket into which the arm inserts is very shallow and therefore the bony aspect of the joint does not offer much support. The way this joint is mainly supported is by the tendons of the musculature that attach at the shoulder and that as a group form the ‘capsule’ that provides stability. (refer to above picture)
A muscle is made up of a muscle belly (the red bit) and a tendon (the white bit). When a tear occurs in a muscle, it most often occurs at the point where the muscle turns into a tendon (red turns white). The second most common place is then the muscle belly and the least common is where the tendon inserts on to the bone. When any of these tears occur, inflammation sets in at that region to try and heal the damage. If this is within the shoulder joint, any where between the top of the humerus (top of the arm) and the underside of the acromion (a sweeping piece of bone that come up and over the top of the arm from the shoulder blade) then this leads to what is known as impingement syndrome.
At this point there is relatively little space due to the bony sandwich upon the tissues between, with inflammation swelling can occur and this space can decrease further and with the inflammation also occurring pain is felt anytime movement causes a further decrease in space. The reason the pain is felt throughout the whole shoulder region is because there is a sac of fluid in the shoulder called the bursa. This sac of fluid is designed to help the smooth motion of the structures within the shoulder. If inflammation occurs locally to this bursa, it can also become inflamed. Due to the bursa being consistent throughout most of the shoulder this means that the pain is felt in a general region in the shoulder and not directly local to the actual area of pain.
The most commonly injured shoulder muscle that may lead to shoulder impingement is the Supraspinatus, this muscle abducts the arm (raising the arm to the side).
With older age shoulder tendons can become ‘worn’ and without proper management when performing harsh activities micro tears may occur, with further exacerbation this may lead to more serious tears or to an increase in Osteoarthritis onset, as instability sets in. When Osteoarthritis sets in (usually seen in the elderly, bony growths can occur as the joint tries to stabilise itsel, this may also lead to shoulder impingement also. These are treated differently to soft tissue impingment as it is a solid piece of bone that may need removing surgically. (see below)
A good Chiropractor is able to determine the exact cause of the shoulder pain and provide home advice and gentle exercises to get the shoulder moving and on it’s way to full function. If there is a suspicion of bony encroachment in the shoulder the Chiropractor will inform you and refer you appropriately to the correct person.