The shoulder and rotator cuff


The supraspinatus muscle originates above the spine of the scapula and inserts on the greater tuberosity of the humerus. The supraspinatus abducts (or elevates) the shoulder joint. It also works with the other rotator cuff muscles to stabilize the head of the humerus in the glenohumeral joint, or shoulder joint.


The infraspinatus muscle originates below the spine of the scapula, in the infraspinatus fossa and inserts on the posterior aspect of the greater tuberosity of the humerus. The infraspinatus externally rotates the shoulder joint. It also works with the other rotator cuff muscles to stabilize the head of the humerus in the glenohumeral joint, or shoulder joint.


The teres minor is a little muscle that lies over the lower end of the back of the shoulderblade and attaches to the humerus. The muscle is below the infraspinatus and often appears to be part of the infraspinatus, although it has its own specific nerve supply. The teres minor helps the infraspinatus to laterally rotate the arm and also helps to 'adduct' the arm; which means it helps bring the arm back towards the body.


The subscapularis muscle roughly does the opposite to the infraspinatus and the teres minor in that it medially rotates the arm. For example, if you throw the end of a scarf over your left shoulder, you are medially rotating your right arm. It also adducts the arm, with help from the teres minor. The subscapularis is a flat, triangular muscle that attaches to the humerus and to the front flat edge of the shoulder blade.


The reason why I'm writing about the rotator cuff is that they are so often neglected, yet perform such an important role. By giving the muscles of the rotator cuff the attention they deserve, we can eliminate the loss of valuable training time to injuries. We tend to concentrate so much on the pretty boy muscles of the pecs, deltoids and lats and forget about the smaller important stabilisers.


Injuries are one of our greatest nightmares for progression in the gym; shoulder injuries being high up with the most common. But with little alterations to our training, by incorporating some rotator cuff strengthening exercise future shoulder injuries can be minimised. Prevention is so much better than the cure.  I'm not saying the exercises will eradicate totally the possibility of injury as wherever there is physical exertion with heavy weights injuries will always be a possibility. But, if we have the correct training strategies in place then risk can be minimised.


Rotator cuff injuries can be really debilitating not only in the gym environment but can effect your daily life. A lot of  these injuries can be caused by over-exercising, lack of exercise, poor form, heavy and improperly controlled weights, or accidents in the gym while using weights.


I think understanding the function of the rotator cuff, then adding some basic rotator cuff strengthening exercises to your workout a couple of times a week can only be beneficial. Or, just wait until the inevitable blow out like me.


If you have a nagging shoulder problem that needs rehabilitating or you'd like advice on exercise choices for your rotator cuff or you need a revamp to your current training sessions contact me.


How many of you have heard of the rotator cuff, know it's function, it's whereabouts and most of all the importance of it in our shoulder mobility. After all the shoulder is the most sophisticated yet complicated joint in the human body.


The shoulder or glenohumeral joint is made up of three bones the scapula, clavicle and humorous and a number of muscles ligaments and tendons. All of these provide the upper extremity with tremendous range of motion such as adduction, abduction, flexion, extension, internal rotation, external rotation and 360° circumduction in the sagittal plane. Furthermore, the shoulder allows for scapular protraction, retraction, elevation, and depression. This wide range of motion also makes the shoulder joint unstable and is a common injury sight for many individuals.


The glenohumeral joint is a ball-and socket joint that is formed between three bones, the humerus, the scapula and the clavicle. The humerus head, acting as the ball, fits into the end of the scapula known as the glenoid fossa. In this specific joint, the humerus head, however, does not fit perfectly within the glenoid because the humerus head is much larger than the surface area of the glenoid socket. This size discrepancy creates a situation where the two bones do not snugly fit together without the help of other physical structures. Thus this joint is dependent upon other structures for stability.


To help keep the larger humeral head in its socket there is articular cartilage or labrum which lies between the humorous (upper arm bone) and the glenoid fossa, this allows a smooth surface for the humorous to rotate around in. But what holds the humerous up in the shallow socket are an important group of muscles. This brings us to the rotator cuff these are four very important muscles which attach the humeral head to the glenoid fossa, the supraspinatus, subscapularis infraspinatus and teres minor.