Trapezius

trapezius

Trapezius is the large external muscle that covers most of the back of your shoulder, neck and upper back. It's upper fibres run from the back of your neck down on to the scapula, they are active in shoulder elevation and lateral flexion of the neck. When you grab the large mucle on the top of your shoulder you've got the upper trapezius. The middle fibres pull your shoulder back while the lower ones pull it down and are involved in scapula rotation.

Tension in it's upper fibres has the effect of pulling your shoulders forward and down like they're carrrying a heavy weight. This common postural presentation and the fact that it is such a large muscle, covering smaller structures with more specific actions, means that it is included in most upper body treatments.

If you're carrying your instrument on a strap over your shoulder it'll be trapezius that is taking the load. The best remedy for this is to open your chest so that your shoulder is not protruding forward, this will transfer the load onto your skeleton which is much more equipped to handle it. The postural strategies in the relaxation section will help out with this.

Serratus Anterior

Serratus anterior is so named because it has a number of seperate sections giving it a serrated apperance. It attaches on the anterior side of the medial border of the scapula and inserts onto the first eight or nine ribs. It is active in rotation and primarily protraction of the scapula.

It's wide base across the lateral rib cage supports a strong pull on the scapula that brings it forward when throwing. Our sedentary lifestyles and tension in the pectoralis muscles mean that serratus anterior is often weak.

It also functions to stabilise a fixed scapula by pulling its medial border into the posterior chest wall. The winging associated with the right shoulder reaching forward to pick the strings pulls this medial border away from the ribs creating fascial tension and eventually pain all along the inside of the scapula.

Levator scapulae

Levator Scapulae is situated at the back of your neck, it originates at the first four cervical vertebrae and attaches on to the medial angle of the scapula. At the top it lies under the sternocleidomastoid but most of it is deep to the large trapezius muscle.

As its name suggests it's primary action is to elevate the scapula. It's involved, along with the upper traps, in lateral flexion (unilaterally) and extension (bilaterally) of the neck. It also acts to stabilise the scapula.

If levator scapulae is chronically tense it won't lengthen to allow the scapula to rotate. This restricts the movement of the shoulder and can cause problems elsewhere. The shoulder introduction explains the role of the scapula in shoulder movement and what can happen when it goes wrong.

When you're tense and you're shoulders lift up it's levator scapulae that is shortening. Notice how when you're on the phone or in the car your shoulders will creep up. It's as if the stress is going directly into levator scapulae. A lot of the relaxation exercises are aimed at releasing this tension.

Holding your instrument on a strap over your shoulder will effect levator scapulae so, as with trapezius, try to keep your chest open to take allow your skeleton to take the load

Pectoralis Major

Pectoralis major is the large muscle at the front of your chest. It attaches to the medial part of the clavicle, the sternum and the medial part of the lower ribs and inserts onto the upper arm where it forms the anterior wall of the axilla ( the front of the armpit).

It is primarily an adductor (it pulls the arm into the body) and a medial rotator of the arm. The upper fibres that attach to the clavicle will also pull the shoulder forward. If your shoulders are rounded, closing off your chest, you'll need to concentrate on the upper part of the muscle.

Pectoralis Minor

Pec minor's insertions onto the ribs make it a secondary respiratory muscle. When the lungs need extra capacity it pulls the ribs up to increase the space in the chest cavity. If you breathe high up in your chest all of the time, rather than allowing your diaphragm to pump the lungs up and down, you'll be overloading pec minor (see the breathing section in the relaxation pages). This area of the chest is also where the Lung meridian hits the surface of the body before travelling down the arm, often indicated in elbow and wrist problems.

The general relaxation exercises and those specific for the shoulder all aim to open out the chest and take the strain off pec minor. If you have a history of lung problems will need to pay particular attention to how your chest moves when you are breathing.

Because most musicians hold their instruments in front of them there will always be a tendency to close off the chest, straining the anterior shoulder muscles. Guitar players particularly tend to bring their right shoulder over the top of the guitar when sitting. The next section on the coracobrachialis and bicep brachii will complete the treatment of the anterior shoulder muscles.

The deep flexors of the shoulder

These two muscles share pec minor's attachment with the coracoid process at the front of the scapula. Bicep brachii is so named because it has two heads, the more lateral long head attaches on the top of the humerus while the short head and the coracobrachialis muscle originate on the scapula. Coracobrachialis lies underneath the bicep inserting onto the inside of the humerus about half way up while the bicep heads converge and insert on to the radius.

Together they will pull the shoulder forward into the familiar rounded shoulder posture as well as assisting in adduction and flexion of the arm at the shoulder joint. Bicep brachii also flexes the elbow.

These two muscles also connect the chest, via the shared attachment with pec minor, to the thumb, via the deep fascia covering the radius.

The deep shoulder flexors, along with pectoralis minor, form a functional group that is often overloaded, pulling the shoulder forward and down. They restrict the movement of the scapula and therefore the whole pectoral girdle and disrupt the balance of forces keeping the shoulder joint stable.

Along with the rotator cuff muscles they help to stabilise the joint by pulling the humerus into the scapula. Pulling it forward and down puts an extra load on the medial rotators, particularly teres major and the shoulders turn inward as well producing the classic round shouldered posture that closes off the chest even further. It also takes the load away from the rhomboids which weaken and are therefore more easily overused when you do need them.

The medial rotators of the shoulder

Subscapularis is the large flat muscle that covers the anterior surface of the scapula, attaching on to the front of the humerus. Teres major originates near the inferior angle of the scapula and forms part of the posterior border of the axilla as it rises up onto the front of the humerus. They both medially rotate the arm at the shoulder joint.

Subscapularis is part of the rotator cuff group that helps stabilise the shoulder joint. It is similar anatomically to the iliacus that covers the inside of the pelvis and attaches on to the femur aiding in its medial rotation at the hip joint. As part of the hip flexor Iliopsoas, iliacus is an important postural muscle and subscapularis also plays an important role in upper body posture.

The relaxation exercises that focus on opening the chest will all help you relax both medial rotators and you'll notice a difference in the openness of your chest after you've treated them.

The lateral rotators of the shoulder

Infraspinatus and teres minor lie at the back of the scapula and reach out onto the back of the humerus. Infraspinatus is the big one, covering most of the infraspinous fossa and teres minor sits just below it. Together they rotate the arm laterally. If you stand in the anatomical position and turn your arms so that your palms face the front then your contracting these two muscles. When you raise your arm to the side in abduction the arm will rotate laterally toward the end of the movement, these two muscles help make that happen.

Both of them, along with suprapinatus and subscapularis share a common tendon, the rotator cuff tendon, that attaches at the back of the head of the humerus. Together they help stabilise the shoulder joint, pulling the humerus into the scapula, especially when the arm is carrying something.

Because these four muscles pull on the one tendon from different directions any dysfunction will put a strain on the tendon, which often becomes thick and painful. If you develop a problem with your rotator cuff I'd suggest you see your health professional. The relaxation exercises will open your chest and take a lot of the load of the rotator cuff and the following massage sequence will be beneficial if you stay away from the shoulder joint and don't do anything that hurts.

Supraspinatus

Supraspinatus is named for its location, superior to the scapula spine. It attaches along the medial section of the supraspinous fossa, the hollow above the scapula spine, and inserts onto the top of the humerus. It assists in abduction of the humerus and plays a significant role in stabilising the shoulder joint as gravity pulls the arm down.

It is part of the rotator cuff group of muscles, sharing its tendon insertion on the humerus with infraspinatus, teres minor and subscapularis. The rotator cuff as a group help stabilise the scapula, pulling the head of the humerus into the glenoid fossa of the scapula.

Deltoid

The deltoid muscle is named for it's triangular shape, like a delta. It has there distinct sections the anterior deltoid attaches on the clavicle, the middle deltoid on the acromion process of the scapula and the posterior fibres on the scapula spine. All three insert on the lateral side of the humerus about a third of the way down.

Because of it's shape it's able to pull in three distinct directions on the one point. While the entire muscle is responsible for abducting the humerus the anterior fibres also play a role in extension and medial rotation while the posterior fibres aid in extension and lateral rotation of the humerus.

Deltoid is a powerful muscle that contributes to most of the movements of the shoulder. Because it produces so much of the force of shoulder movements a lot of the other structures in the shoulder are active stabilsing the pectoral girdle to give it a base to pull from.

The right shoulder is abducted to varying degrees when you play your guitar and the deltoid is the primary muscle that maintains this position.

Rhomboids

The rhomboids originate on the upper thoracic vertebrae and run obliquely onto the medial border of the scapula. They share a fascial connection on the inside of the medial scapula with serratus anterior, the lower serrations of which extend this oblique line onto the side of the rib cage.

The guitarists tendency to roll his or her shoulder forward and wing the scapula places lot of strain on these two muscles, particularly at the medial border of the scapula which often becomes painful toward the inferior angle. The next page on shoulder biomechanics explains the role of these two muscles in stabilising the scapula.