"I Think It's My Rotator Cuff"

The above statement has become something of a stock response to shoulder injury or pain. The truth is quite the opposite. With a few exceptions, most shoulder injuries are not the rotator cuff’s fault. It is just a victim. 

The shoulder’s unique anatomy, which allows the arm to move in multiple directions, contributes to a high incidence of shoulder problems like dislocations, tendonitis, and torn rotator cuffs. The shoulder, like the hip, is a ball and socket joint, which is normally pretty stable since most are comprised of a large “socket” into which the “ball” (end of the bone) fits nicely. The shoulder, however, is made up of a ball larger than its socket to allow for dynamic range of motion. This means all stabilization is left up to the surrounding muscles, ligaments, and tendons, primarily the rotator cuff.

What Is The Rotator Cuff Made Of?

The rotator cuff consists of four muscles all based around our scapula (or shoulder blade) and attach themselves from the scapula over to the humerus (your arm bone). The muscles are called Subscapularis, Teres minor, Supraspinatus and Infraspinatus. The way in which these 4 muscles attach to the humerus is shaped like a cuff, wrapped around the superior head of the bone.

What Does The Rotator Cuff Do?

Each muscle has a slightly different role to play in movement; subscapularis for example helps to abduct your arm, raising it over your head. This is the muscle most susceptible to injury for the average gym goer as the muscle runs through a small gap between bones known as the subacromial space. It can become inflamed or irritated if excessive abduction is performed, or if not warmed up effectively, and eventually causing impingement syndrome.

Infraspinatus can be quite tender when treated, but this is because it’s one of the easiest to palpate, and sits directly on top of the lower part of the scapula. The infraspinatus action is to laterally rotate the arm. An example of this would be performing breast stroke in swimming, or during a back swing in tennis. The infraspinatus will aid in pulling your arm out to the side through what we call external rotation. The Teres minor pairs up with infraspinatus functionally however has a slightly secondary function

Subscapularis muscle is much harder to reach, as it sits between your scapula and your ribs, this means for the therapist to have any palpation they will need to go under your shoulder blade. The primary sport that may affect it is boxing as the subscapularis function is to medially rotate the Humerus, contrasted with the infraspinatus. As a boxer performs most types of punches, the subscapularis will be doing a lot of work.

Stay On The Court This Summer

Hitting a tennis ball puts stress on specific joints, muscles, and tendons. Whether you’re serving or hitting a forehand, the mechanics involved in swinging a racquet can cause pain and discomfort. Tennis players need to assess the specific body parts that endure the most stress, and strengthen those muscles accordingly.

Most tennis injuries result from overuse. Players continually use the same muscles, and they can eventually breakdown over time through these consistent repetitive forces. The shoulder joint is among the most commonly affected body parts for tennis players. To avoid such injuries, you need to target and strengthen your shoulder muscles making sure that there are no weaknesses or imbalances causing incorrect joint movement.

Do not over-focus on the nature of the injury, while ignoring the mechanism of the injury:

When you’re talking about cuff injuries, in most cases the problem didn’t originate with the cuff itself, but much of late-stage rehab will involve rotator cuff strengthening. If you’re a tennis player, or involved in any other sport that puts a great deal of strain directly on the cuff, then that approach makes some sense. If your shoulder injury was the result of working out and lifting weights, this approach pretty much disregards the true mechanism of injury. 

Scapular stability and positioning is the common culprit. The muscles around your scapulae, such as trapezius and rhomboids, are enormous in comparison to the small rotator cuff muscles. If these muscles around your scapulae are weak and your scapulae are immobile, no amount of rotator cuff strengthening is going to be able to pick up their slack.

Structurally if you imagined putting a tennis ball on the top of a baseball bat, then turning it onto its side, that’s what the shoulder (glenohumeral joint) looks like. It heavily relies on ligaments, muscles and other structures to hold it in place.