Monday, 8 November 2021

The Rotator Cuff - the 4 muscles that stabilise the shoulder and move the arm.

I treat many clients for shoulder pain and sometimes they explain to me they think or have been told they have a rotator cuff problem, so, I‘d like to explain more about the Rotator Cuff as this is quite a general term.

The Rotator Cuff is a name used for 4 muscles which work together to co-ordinate the movement of your arm bone (humerus) in relation to your shoulder blade (scapula). These muscles and their tendons surround and attach around the top of the humerus (like a cuff!).

The rotator cuff muscles have the job of elevating and rotating the arm and importantly stabilising the shoulder, ensuring that the head of the humerus stays securely placed in the centre of the shoulder socket. The 4 rotator cuff muscles are the — Infraspinatus, Teres minor, Subscapularis and Supraspinatus (which is the most common one people have heard of owing to injuries). 

Before I further describe the rotator cuff muscles it is important to understand a bit more about the shoulder as a joint.

The shoulder has 4 joints

Our shoulders have the greatest freedom of movement available in our bodies, which is why we can reach above our heads, scratch in between our shoulder blades and windmill our arms etc. Generally we call where the top of the humerus meets the top of the shoulder THE shoulder joint but actually the shoulder has 4 joints and this one is called the glenohumeral joint (see image above).

The glenohumeral joint is a ball and socket joint and the ball, the humeral head, is small and the socket is not deep plus the shoulder capsule (soft tissue that surrounds the joint) is loose. So, this structure allows our wonderful 360° shoulder movement however this movement has developed at the expense of joint stability! And stability is the key role of the rotator cuff.

Rotator Cuff muscles keep the humeral head centralised

It is useful to know that there are 4 joints of the shoulder as the glenohumeral joint and the rotator cuff muscles rely on free movement of the other 3 joints. So the joints in addition to the glenohumeral joint are:

Sternoclavicular - connecting the medial end of the collar bone ( clavicle) to the breast bone (sternum)
Acromioclavicular joint - connecting the lateral end of the collar bone to the acromion (which is the front boney flat bit on top of the shoulder). See image above.
Scapulothoracic joint - connecting the shoulder blade (scapula) to the soft tissues of the thoracic (mid back area). This is not a true joint as it is bone to soft tissue, rather than the meeting of two bones.

So, for the shoulder to move freely, controlled and pain free there has to be balance between movement and stability and it is the rotator cuff muscles, all working together, that provide the muscular forces to provide joint stabilisation and the ideal alignment of the humeral head, centralised in the glenohumeral joint. With any shoulder movement there are constant competing mobility and stability demands and combined with an intricate shoulder structure this means the rotator cuff muscles are constantly adjusting to demand.

Think again about all the different positions and actions we do with our arms, from throwing a ball, a tennis serve, reaching up to a high shelf, stirring a cake mix, itching our back or a golf swing and the range of movement we take our arms through and often at pace too!

Understanding the shoulders set up and all the demands we place on our shoulders we can better understand that they can be susceptible to dysfunction and injury. Any dysfunction at one of the shoulder joints or one of the rotator cuff muscles will impact on the rotator cuff’s ability to perform and hence the arm to move freely.

Rotator Cuff injuries

There are certain movements and activities that increase the likelihood of suffering a rotator cuff injury, such as:

Overhead tasks - painting, cutting
Repetitive stress from sport (like throwing, swimming, golf)
Postural neglect - rounded shoulders
Contact sports

Plus, normal wear and tear, ageing, conditions that effect the joint like arthritis, an accident or fall also can result in rotator cuff injury.

If one of the rotator cuff muscles becomes injured, inflamed, weak or are comprised by poor postural habits of the neck, back and shoulders then the shoulder becomes unbalanced. This could mean the humeral head is decentred and often this leads to pain in certain directions of movement or sleeping on the shoulder. Impingement of the Supraspinatus tendon can occur too, as the tendon gets squashed in between boney structures. You may feel something is catching or have referred pain down the arm and a common feeling is pain at the back of the top of the arm.

It is important we move and exercise to maintain healthy joints, avoiding too much overhead and repetitive strain on your shoulders and maintaining proper posture can help to avoid painful shoulders.

How Massage can help?

Massage treatment at the shoulders helps to restore your range of movement by helping to release and recover overused muscles and restore good alignment of the shoulder joints. Treatment will focus on massage around the shoulder, neck and back, stretching and passive and active movement of the joints allowing greater blood flow to the muscles and joint. Plus, I advice on self-care and rehab exercises to restore function and strength to minimise the risk of re-injury.

Any questions please don’t hesitate to contact me.

Nicky Holbrook  

November 2021