Muscles flexing the arm at the shoulder joint

Pectoralis major

Deltoid – anterior fibres

Biceps brachii – long head

Coracobrachialis

Pectoralis major

Pectoralis major is found on the upper half of the anterior surface of the thoracic wall. It is a thick triangular muscle with clavicular and sternocostal parts, which may be separated by a groove, although they are usually continuous with each other. On their way to the humerus, the twisting fibres of pectoralis major from the rounded anterior fold of the axilla.

The smaller, clavicular attachment of pectoralis major is from the medial half of the anterior surface of the clavicle; the larger, sternocostal attachment comes from the anterior surface on the manubrium and body of the sternum, the anterior aspects of the upper six costal cartilages, the anterior part of the sixth rib as well as the aponeurosis of the external oblique muscle of the abdomen.

From this large central attachment, the muscle narrows and inserts via a laminated tendon into the lateral hip of the intertubercular groove of the humerus. The anterior lamina, which comprises the clavicular part of the muscle, runs to the lower part of the humeral attachment. Fibres from the sternocostal part of the chest wall form the posterior lamina, which passes upwards behind the anterior lamina to the upper part of the attachment of the muscle to the humerus. In this way the tendon comes to resemble a U in cross-section. The posterior part blends with the shoulder joint capsule, while the anterior, clavicular fibres blend with the attachment of deltoid.

As the most superficial of the muscles of the anterior thoracic wall, pectoralis major lies on top of pectoralis minor, the ribs and serratus anterior. In the female, the muscle is covered by the breast; indeed the fibrous septa of the breast are attached to the deep fascia overlying pectoralis major. Pectoralis major is separated from deltoid by the deltopectoral groove(the infraclavicular fossa) in which lie the cephalic vein and branches from the thoracoacromial artery.

Nerve supply

Pectoralis major is supplied by the medial(C8, T1) and the lateral(C5, 6, 7) pectoral nerves; the clavicular part by roots C5 and 6, and the sternocostal part by C7, 8 and T1. The skin over pectoralis major is supplied by roots T2 to T6.

Action

Pectoralis major as a whole is a powerful adductor and medial rotator of the humerus at the shoulder joint. In addition to the clavicular part can flex the humerus to the horizontal, while the sternocostal fibres, because of their direction, can extend the flexed humerus, particularly against resistance to the anatomical position. With the humerus fixed, as in gripping a bed table or chair back, pectoralis major pulls on the upper ribs to assist inspiration during respiratory distress.

Functional activity

Pectoralis major is one of the major climbing muscles, so that if the arms are fixed above the head, the massive power of the muscle can be used to pull the trunk upwards. It is assisted in this activity by latissimus dorsi. In pushing, punching and throwing movements, pectoralis major acts to move the humerus forwards forcefully, whilst serratus anterior and pectoralis minor simultaneously protract the pectoral girdle.

In exercises, such as the “press-up”, pectoralis major contracts concentrically on the upward movement and eccentrically on the downward pressure. The sternocostal part is best palpated if this same position is maintained against an upward pressure. The integrity of the muscle can be tested by adduction of the arm against resistance.

Biceps brachii

Biceps brachii is a prominent fusiform muscle on the anterior aspect of the arm. It arises by two tendinous heads as its upper end, and attaches by one tendinous heads at its upper end, and attaches by one tendinous insertion at its lower end. The upper end is covered by deltoid and pectoralis major, but the main part of the muscle is only covered by skin and subcutaneous fat.

The short head of biceps brachii arises by a flat tendon, shared with coracobrachialis, from the apex of the coracoid process of the scapula. The long head arises from the supraglenoid tubercle of the scapula and the adjacent glenoid labrum of the shoulder joint. The tendon of the long head runs within the shoulder joint wrapped in a synovial sleeve and leaves to enter the intertubercular groove by passing deep to the transverse humeral ligament. The two fleshy bellies continue towards the elbow with the two heads fusing to form with the two heads fusing to form a single muscle just below the middle of the arm. At the elbow, a single flattened tendon is formed which twists through 90° before attaching to the posterior part of the radial tuberosity. A bursa separates the tendon from the remainder of the radial tuberosity. The prominent bicipital aponeurosis, a strong membranous band arising from the lateral side of the main tendon, runs downwards and medially across the cubital fossa, in front of the brachial artery and median nerve, to attach to the deep fascia on the ulnar side of the forearm.

Nerve supply

Biceps brachii is supplied by the musculocutaneous nerve, root value C5, and 6. The skin over biceps is supplied by the roots C5, 6, T2 and T3.

Action

Biceps brachii is not only an important flexor of the elbow joint, but also a powerful supinator of the forearm. Often these two actions are performed together with any unwanted actions being cancelled by antagonists. Maximum power is achieved for both flexion and supination with the elbow at 90°. When the elbow is fully extended the supinating action of biceps is lost. Biceps is also a flexor of the shoulder joint, and the fact that the long head crosses the superior part of the joint means that it has an important stabilizing role.

Functional activity

Biceps may use its supinatory and flexing actions sequentially in an activity, as, for example, in inserting a corkscrew and pulling out the cork. During this activity the head of the ulna may move medially due to the force of the biceps contraction transmitted to its posterior border via the bicipital aponeurosis.

When deltoid is paralysed, the long head of biceps can be re-educated to abduct the shoulder. This is accomplished by laterally rotating the humerus at the shoulder joint in order to put the long head into a more appropriate position.

Palpation

With the elbow flexed to 90° and the forearm pronated, the muscle can be felt contracting in the middle of the arm when supination against resistance is attempted.

The lower part of the muscle is easily palpated through the skin. Proximally, each tendon may be palpated but with some degree of difficulty. The tendon of the long head lies between the two tubercles. Having determined these, firm deep pressure between them is needed to locate the tendon. This is the point at which deep transverse frictions or electrical treatments are applied when the tendon becomes inflamed.

The short head can be found by first palpating the apex of the coracoid process, and then placing the fingers just below it. As the elbow is flexed, the tendon can be felt to stand out.

At the elbow, the tendon of insertion is best palpated with the elbow flexed to 20°. In this position it can be easily gripped between the index finger and thumb. If, in this same position, the subject is asked to resist a strong downward pressure on the forearm, the upper border of the bicipital aponeurosis can be seen and felt as a crescentic border running downwards and medially from the main tendon.

The tendon of biceps is the point at which the biceps reflex is tested, often by the examiner placing his or her thumb over the tendon and then tapping it with a patella hammer. The resultant reflex contraction can be felt below the thumb and biceps may be seen contracting if the reflex is brisk enough.

Coracobrachialis

Coracobrachialis is the only true representative in the arm of the adductor group of muscles found on the leg. It arises via a rounded tendon, in conjunction with the short head of biceps brachii, from the apex of the coracoid process of the scapula and attaches by a flat tendon to the medial side of the shaft of the humerus at about its midpoint, between triceps and brachialis. Some fibres may continue into the medial intermuscular septum of the arm.

Nerve supply

Coracobrachialis is usually supplied by the musculocutaneous nerve as it pierces the muscle, root value C6, 7. However, the nerve to coracobrachialis may arise directly from the lateral cord of the brachial plexus. The skin over the muscle is supplied by roots T1 and T2.

Action

Coracobrachialis is an adductor and weak flexor of the arm at the shoulder joint.

Palpation

Coracobrachialis can be seen and felt as a rounded muscular ridge on the medial side of the arm when it is fully abducted and then adducted against resistance.

Muscles abducting the arm at the shoulder joint

Supraspinatus

Deltoid

Supraspinatus

Supraspinatus arises from the medial two-thirds of the supraspinous fossa and the deep surface of the dense fascia which covers the muscle. The muscle and the tendon which forms within it pass laterally below trapezius, the acromion process and the coracoacromial ligament to cross over the top of the shoulder joint. The tendon of supraspinatus blends on its deep surface with the capsule of the shoulder joint prior to inserting into the upper of the three facets on the greater tubercle of the humerus.

Nerve supply

Supraspinatus is supplied by the suprascapular nerve, root value C5, 6, a branch from the upper trunk of the brachial plexus. The skin over the muscle is supplied from roots C4 and T2.

Action

Supraspinatus initiates the process of abduction at the shoulder joint, being more important during the early part of the movement than later when deltoid takes over. The role of supraspinatus is probably twofold during this movement. It braces the head of the humerus firmly against the glenoid fossa to prevent an upward shearing of the humeral head( this has been likened to a “foot on the ladder” where a small force applied at one end will produce a rotatory rather than a shearing movement) while at the same time producing abduction. After the initial 20° of abduction, when the stronger deltoid takes over, supraspinatus acts to hold the humeral head against the glenoid fossa.

Functional activity

Supraspinatus is one of the four muscles which form a musculotendinous cuff(or rotator cuff) around the head of the humerus. They function to keep the head of the humerus in the glenoid fossa during movements of the shoulder joint.

Palpation

Contraction of supraspinatus can be felt through trapezius if the examiner’s fingers are pressed into the medial part of the supraspinous fossa when the subject initiates abduction at the shoulder joint. In the anatomical position, the tendon of supraspinatus is covered by the acromion process but it can be palpated if the subject medially rotates the shoulder with his or her hand resting passively in the small of the back. During this manoeuvre, the greater tubercle moves anteriorly so that the tendon can now be rolled against the bone by a medial to lateral pressure of the examiner’s finger against the tubercle. The tendon of supraspinatus is the most frequently damaged soft tissue in the shoulder region and techniques, such as transverse frictions, injection and ultrasound are often applied to this exact location. In severe cases the tendon may be  sufficiently eroded to cause its rupture, which then affects the ease with which abduction can occur. In such cases, or when supraspinatus is paralysed, the patient can still initiate abduction by leaning slightly to the side so using gravity. Alternatively, the patient may use the opposite arm to push the affected limb away from the side, or jerk the hips to “kick” the elbow out. By each of these actions a small yet sufficient degree of abduction occurs to enable the powerful deltoid to take over.

Deltoid

Deltoid is a coarse, thick, triangular muscle which gives the shoulder its rounded contour. Functionally it can be divided into three parts, anterior, posterior and middle, of which only the middle portion is multipennate. It has an extensive attachment to the pectoral girdle. In front, the fibres attach to the anterior border of the lateral third of the clavicle, whilst behind, they come from lower lip of the crest of the spine of the scapula. The most anterior and posterior fibres both run obliquely, in an uninterrupted manner, to the deltoid tuberosity on the lateral surface of the shaft of the humerus.

The middle muscle fibres are more complex because of their multipennate arrangement. These shorter oblique fibres run from four tendinous slips which are attached to the lateral margin of the acromion process to join three intersecting tendinous slips which ultimately run to the deltoid tuberosity of the humerus. Consequently, these shorter, more numerous middle fibres of deltoid, working under considerable mechanical disadvantage when active, give this part of the muscle great strength.

Deltoid is separated from the coracoacromial arch and the upper and lateral aspects of the shoulder joint(and the tendons lying on it) by the subacromial bursa.

Nerve supply

Deltoid is supplied by the axillary nerve, root value C5, 6. The skin covering deltoid is supplied by roots C4 and 5.

Action

Deltoid is the principal abductor of the arm at the shoulder joint, the movement being produced by its middle, multipennate fibres. However, deltoid can only produce this movement efficiently after it has been initiated by supraspinatus.

The true plane of abduction is in line with the blade of scapula, that is in slight flexion, and for this the anterior and posterior fibres are active in order to maintain the plane of abduction by acting as “guy ropes”. The tendency for deltoid to produce an upward shearing of the head of the humerus is resisted by the muscles of the rotator cuff, that is by subscapularis anteriorly, teres minor and infraspinatus posteriorly, and supraspinatus from above.

The anterior part of deltoid is a strong flexor and medial rotator of the humerus, while the posterior part is a strong extensor and lateral rotator, and can help in the transfer of the strain of heavy weights carried in the hand to the pectoral girdle. The posterior part of deltoid is also active during adduction of the arm, to counteract the medial rotation produced by pectoralis major and latissimus dorsi.

Functional activity

Deltoid is active in abduction when the middle fibres contract concentrically, but the massive development and multipennate nature of the muscle are probably due to the fact that many activities of the upper limb require that it be maintained or “held” in this position for long periods of time. Consequently, the middle fibres contract statically when performing activities with the arms in front of the trunk; they than lower the arm back to the side by operating in an eccentric mode.

Palpation

If the seated subject is asked to raise the arm to 60° of abduction in the plane of the scapula, the triangular bulk of deltoid can be felt and seen. Palpating the upper surface of the acromion process and moving the fingers laterally from its edge, the depressions in the muscle caused by the tendinous intersections can be felt if anteroposterior pressure of the fingers is applied.

The anterior and posterior fibres can be made to stand out more clearly if, in the same position as above, the subject is asked to maintain the position against resistance first anteriorly and then posteriorly.

Paralysis of deltoid severely affects the functioning of the shoulder joint and therefore of the upper limb.

Dejan Zivkovic Sartid - Radnicki(K) goal half way line

Best goal celebrations ever!

Movements of the shoulder joint

The movements of the shoulder joint will be considered as follows:

-         Abduction and adduction in the coronal plane

-         Flexion and extension in the sagittal plane

-         Medial and lateral rotation about the long axis of the arm

Muscles stabilizing the clavicle

Subclavius

Subclavius lies entirely beneath the clavicle under cover of pectoralis major. The small, fleshy belly of this muscle attaches to the floor of the subclavian groove on the under surface of the clavicle. The fibres converge and pass medially, becoming tendinous, to attach to the first rib near its junction with the costal cartilage. 

Nerve supply

Subclavius is supplied by the nerve to subclavius, root value C5,6 which arises from the upper trunk of the brachial plexus.

Action

The principal action of subclavius is to steady the clavicle by pulling it towards the disc of the sternoclavicular joint and the sternum during movements of the pectoral girdle. This action tends to depress the lateral end of the clavicle. Paralysis of subclavius has no demonstrable effect.

Muscles medially rotating the pectoral(shoulder) girdle

Rhomboid major

Rhomboid minor

Pectoralis minor

Levator scapulae

Movement of the inferior angle of the scapula towards the vertebral column is frequently produced by the action of gravity, being controlled by the eccentric activity of the lateral rotators. However, the above muscles contract strongly if the pectoral girdle is to be medially rotated against resistance, as when moving the weight of the body from a position of hanging from a bem to full chin-up. The notional axis of rotation is just below the spine of the scapula, towards the base. Pectoralis minor exerts a downward pull on the lateral side of this axis via its attachment to the coracoid process, while the rhomboids and levator scapulae pull upwards on the medial side. The resultant movement is shown in the picture below.

Muscles laterally rotating the pectoral(shoulder) girdle

Trapezius

Serratus anterior

As it can be seen in the pictures below, both muscles are well positioned to cause the inferior angle of the scapula to move laterally around the thoracic wall. The clavicle acting as a strut restricts movement at the acromion process, so that the overall effect of the action of these two muscles is to elevate the acromion process and move the inferior angle laterally, thereby enabling the glenoid fossa to face more directly upwards. This movement of the pectoral girdle is extremely important for increasing the range of movement possible, particularly in terms of abduction and flexion of the upper limb at the shoulder.

Trapezius contributes to the rotation by contraction of its upper fibres which lift the lateral end of the clavicle and acromion process upwards while at the same time its lower fibres pull downwards on the medial end of the spine of the scapula.

Serratusanterior, the more important of the two muscles in this movement, pulls strongly on the inferior angle of the scapula, where the majority of its muscle fibres insert, to pull it laterally around the chest wall. The notional axis about which this rotation takes place is just below the spine of the scapula towards the base. Resultant movements are shown in the picture below. 

Muscles elevating the pectoral(shoulder) girdle

Trapezius(upper fibres)

Levator scapulae

Levator scapulae

Levator scapulae is situated in the posterior part of the neck, its upper part under cover of sternomastoid and its lower part deep to trapezius. Its middle portion forms part of the floor of the posterior triangle. It lies superficial to the extensor muscles of the neck and attaches by tendinous slips to the transversae processes of the upper three or four cervical vertebrae(attaching to the posterior tubercles of the lower two) behind the attachment of scalenus medius. From here the fibres run downwards and laterally to attach to the medial margin of the scapula between the superior angle and base of the spine.

Nerve supply

Levator scapulae receives its nerve supply partly from the dorsal scapular nerve(C5) and directly from the ventral rami of C3 and 4.

Action

Working with trapezius, levator scapulae can produce elevation and retraction of the pectoral girdle or resist its downward movement, as when carrying a load in the hand. Again when working with trapezius, contraction of both sides produces extension of the neck, while one side produces lateral flexion of the neck. Levator scapulae also helps to stabilize the scapula and is active in resisted medial rotation of the scapula.

Palpation

Levator scapulae can be palpated when trapezius is not contracting(as for the rhomboids), with the subject upright and the hands in the small of the back. Levator scapulae can be felt anterior to trapezius in the posterolateral part of the neck when the hand is moved backwards with the elbow flexed.

Muscles protracting the pectoral(shoulder) girdle

Serratus anterior

Pectoralis minor

Serratus anterior

Serratus anterior is a large flat muscular sheet covering the side of the thorax, being sandwiched between the ribs and the scapula. Loose fascia exists between the deep surface of the muscle and the ribs or intercostals fascia, and also between its superficial surface and subscapularis in order to facilitate free movement of the scapula. Serratus anterior forms the medial wall of the axilla, and is partly covered by the breast inferolaterally. The upper digitations are behind the clavicle while latissimus dorsi crosses its lower border.

Serratus anterior attaches by fleshy digitations just beyond the midaxillary line to the outer surfaces of the upper eight or nine ribs and the intervening intercostal fascia. The upper digitations arises from ribs one and two, whereas each of the remaining digitations arise from a single rib. The lower four digitations interdigitate with the costal attachment of the external oblique of the abdomen.

From this extensive attachment the muscle fibres run backwards to insert into the costal surface on the medial border of the scapula between the superior and inferior angles. The digitations are not however evenly distributed in their attachment to the scapula. The first passes almost horizontally to the superior angle, while the lower four condense to attach to the inferior angle, with the intervening ones spread along the medial border.

Nerve supply

Serratus anterior is supplied by the long thoracic nerve, root value C5, 6, 7, with the first two digitations supplied by C5, the next two by C6 and the remaining four by C7. The nerve enters the muscle on its superficial aspect. The skin over the accessible parts of the muscle is supplied by nerves with root values of T3 to T7.

Action

Serratus anterior is a major protractor of the pectoral girdle and as such is involved in all thrusting, pushing and punching movements where the scapula is driven forwards carrying the upper limb with it. Note the massive development of this muscle in boxers.

Serratus anterior plays a vital role in stabilizing the scapula during movements of the upper limb and contracts strongly to hold the medial border of the scapula against the chest wall when the arm is flexed or when a weight is carried in front of the body. Failure to perform this action, as when paralysed, results in “winging” of the scapula where the medial border stands away from the chest wall, thus severely affecting the function and mobility of the upper limb.

The lower digitations of the muscle work together with trapezius to rotate the scapula laterally, so that the glenoid fossa looks upwards and forwards. When paralysed, the loss of the rotating action of serratus anterior means that the upper limb cannot be abducted by more than 90°, thereby seriously limiting the functional capacity of the limb. There is some controversy as to whether serratus anterior acts as an accessory muscle of inspiration during respiratory distress. The line of action of the muscle fibres, except perhaps for the first two digitations and maybe the last, are not directed to cause elevation of the ribs. Indeed, they are more likely to cause depression of the ribs.

Palpation

In a muscular subject the digitations of serratus anterior can be felt and often seen running forwards in the region of the midaxillary line, especially when performing “press-ups”.

Pectoralis minor

Pectoralis minor is a thin, flat, triangular muscle situated on the anterior chest wall deep to pectoralis major. Inferiorly it attaches to the outer surfaces of the third, fourth and fifth ribs close to their costal cartilages and the intervening intercostal fascia. There may be additional attachments to the second or sixth rib, or more rarely, to both. The fibres converge to a short, flat tendon as they pass superolaterally to attach to the upper surface and medial border of the coracoid process of the scapula.

Nerve supply

Pectoralis minor is supplied by the medial pectoral nerve which pierces it. However, within the axilla the medial and lateral pectoral nerves communicate, thereby ensuring that pectoralis minor is supplied by both pectoral nerves. The segmental supply is by C6, 7 and 8.

Action

By exerting a strong pull on the coracoid process, the scapula can be pulled forwards and downwards during pushing and punching movements. When leaning on the hands it helps to transfer the weight of the trunk to the upper limb. The nature of its attachment to the coracoid process allows pectoralis minor to help produce medial rotation of the scapula against resistance(figure b). With the scapula and upper limb fixed, pectoralis minor may be used as an accessory muscle of inspiration during respiratory distress.

Palpation

Contraction of pectoralis minor, lying deep to the great bulk of pectoralis major, is difficult to palpate. 

Muscles retracting the pectoral(shoulder) girdle

Rhomboid minor

Rhomboid major

Trapezius

Rhomboid minor

Rhomboid minor is a small quadrilateral muscle whose fibres run obliquely downwards and laterally from the spinous processes of C7 and T1 and the supraspinous ligament between them and the lower part of the ligamentum nuchae, to attach the medial border of the smooth triangular area at the base of the spine of the scapula.

Rhomboid major

Rhomboid major, although larger than rhomboid minor, may be continuous with it. It arises by tendinous slips from the spinous processes of T2 to T5 inclusive and the intervening supraspinous ligament. The muscle fibres run obliquely downwards and laterally to attach to a medial border of the scapula between the base of the spine and the inferior angle.

Both rhomboids lie superficial to the long back muscles, being themselves covered by trapezius, except for the lower border of rhomboid major which forms the floor of the “triangle of auscultation”.

Nerve supply

Both rhomboid muscles are supplied by the dorsal scapular nerve, root value C5.

Action

The rhomboids act principally to retract the scapula but are also active, however, in medial rotation of the pectoral girdle. In addition they also act as important stabilizers of the scapula when other muscle groups are active.

Palpation

With the subject’s hand placed in the small of the back(to relax trapezius), the rhomboids can be palpated through trapezius when the hand is moved backwards. Contraction of the rhomboids can be felt(and occasionally be seen) between the medial border of the scapula and the vertebral column.

Trapezius

Trapezius is a large, flat triangular sheet of muscle extending from the skull and spine medially to the pectoral girdle laterally. It is the most superficial muscle in the upper back and with its fellow of the opposite side it forms a trapezium, hence its name.

The medial attachment of trapezius runs from the medial third of the superior nuchae line and external occipital protuberance of the occipital bone, the ligamentum nuchae, the spinosus processes of C7 to T12 inclusive and the intervening supraspinous ligament. The majority of this attachment is by direct muscular slips, however a triangular aponeurosis exists in trapezius between C6 and T3 which corresponds to a hollow seen in the living subject.

From this extensive central attachment the upper fibres of trapezius run downwards and laterally, the middle fibres almost horizontally, and the lower fibres upwards and laterally to form a continuous line of attachment to the clavicle and scapula. The upper fibres descend to the posterior border of the lateral third of the clavicle, while the middle fibres pass to the medial border of the acromion and upper border of the crest of the spine of the scapula, being separated from the smooth area on the medial part of the spine by a small bursa. The lower-most fibres converge to a tendon which attaches to the tubercle on the inferior edge at the medial end of the spine of the scapula.

The upper free edge of trapezius forms the posterior border of the posterior triangle of the neck, while the lower free border forms the medial boundary of the triangle of auscultation. This latter triangle is an area of the chest wall free of bony obstruction by the scapula and thinly covered by muscle. Its other boundaries are the upper border of latissimus dorsi below and the medial border of the scapula laterally.

Nerve supply

Trapezius receives its motor supply via the spinal part of the accessory nerve(XI) which enters it from the posterior triangle. It also receives sensory fibres from the ventral rami of C3,4 via the cervical plexus. The skin over trapezius is supplied by the dorsal rami of C3 – T12.

Action

Trapezius has an important function in stabilizing the scapula as a base for movements of the upper limb. The middle horizontal fibres pull the scapula backwards towards the midline, that is retraction, and may be aided by the upper and lower fibres contracting together to produce a “resolved” force towards the midline. The upper fibres of trapezius elevate the pectoral girdle and maintain the level of the shoulders against the effect of gravity, or when a weight is being carried in the hand. When both left and right muscles contract they can extend the neck, but when acting singularly the upper fibres produce lateral(side) flexion of the neck. The lower fibres pull down the medial part of the scapula and thus lower the shoulder, especially against resistance, for example when using the arms to get out of a chair. The upper and lower fibres working together produce lateral rotation of the scapula about a point towards the base of the spine. Trapezius is thus important in the overall function of the upper limb as its action increases the possible range of movement.

Paralysis of trapezius, particularly its upper part, results in the scapula moving forwards around the chest wall with the inferior angle moving medially. The usually smooth curve of its upper border between the occiput and the acromion process may become markedly angulated.

Palpation

To demonstrate and palpate all three parts of trapezius, the subject should abduct both arms to 90°, flex the elbows to 90° and then rotate them laterally so that the fingers are pointing upwards.

In this position the three sets of fibres can be readily palpated; in a lean subject the contraction of the various parts of the muscle can be seen. For the lower fibres of trapezius the contraction can be further enhanced by asking the subject to clasp his or her hands together above the head and pull hard.

Soft tissue techniques are often applied to the upper muscular fibres of trapezius in the presence of muscle spasm secondary to neck pain, with the aim of inducing relaxation. Deep transverse frictions can also be applied to the tendinous attachment of trapezius on the superior nuchal line when this is the site of a lesion causing pain in the neck or occipital region.