The upper limb

2 The upper limb





Bones



The pectoral region


The bones in this region comprise the clavicle and scapula. These bones form the pectoral girdle, with the upper end of the humerus situated vertically under its lateral margin. The clavicle is situated on the upper part of the anterolateral aspect. The scapula is situated on the upper part of the posterolateral aspect of the chest wall. The humerus is the upper bone of the arm articulating with the glenoid [glene (Gk) = a socket] cavity of the scapula at the shoulder (glenohumeral) joint.



The clavicle (Fig. 2.1)


The clavicle [clavis (L) or kleis (Gk) = key; also, clavis (L) = an S-shaped bar for striking a gong] is a bone about 10 cm long and situated between the manubrium sterni medially and the acromion process of the scapula laterally (Fig. 2.1). It is a long bone and is a shallow S-shape when viewed from above. It ossifies in membrane, which means that its articular surfaces are covered with fibrocartilage and it has no medullary cavity.





Palpation


For palpation in this region, the model should be in the sitting position.



The sternal (jugular) notch. Palpate the sternal (jugular) notch which is located centrally, at the lower boundary of the front of the neck. This is formed by the superior border of the manubrium sterni inferiorly and the medial end of each clavicle on either side. Articular cartilage together with an interarticular disc and interclavicular ligament are interposed between the medial ends of the clavicles and the skin.


The medial third of the clavicle. Move your hands laterally and you will palpate the medial third of the bone which is convex forward with a superior and anterior surface. These features are easily palpable despite giving attachment to the sternocleidomastoid muscle superiorly and pectoralis major muscle anteriorly.


The anterior end of the first rib. Now move your hands downwards to palpate the anterior end of the first rib. It is easily identifiable where it articulates with the lateral border of the manubrium sterni.


The middle third of the clavicle. If you move your hands further laterally, you will notice that the middle third of the clavicle begins to curve backwards, being a little more rounded in cross-section.


The supraclavicular fossa. Posterior to the superior surface of the clavicle you will palpate a depression: the supraclavicular fossa. This fossa contains the cord-like structures of the trunks of the brachial plexus running downwards and laterally towards the upper limb.


The upper surface of the first rib. If you now apply deep, but careful, pressure in this notch in an inferomedial direction, you will be able to palpate the upper surface of the first rib, over which the trunks of the brachial plexus pass.


The lateral third of the clavicle. You will notice that the lateral third of the clavicle becomes flattened from above down and that its sharper anterior border is concave forward. Its subcutaneous superior surface can be easily palpated through the skin, becoming thicker at the lateral end toward the acromioclavicular joint.


The infraclavicular fossa. Below the anterior border of the clavicle you will palpate a depression: the infraclavicular fossa. This fossa is situated between the deltoid muscle laterally and pectoralis major inferomedially.


The coracoid process of the scapula. The coracoid [korax (Gk) = a crow and oeides (Gk) = shape] process lies within the infraclavicular fossa and you can palpate its tip lying approximately 3 cm below the junction of the middle and lateral thirds of the anterior border of the clavicle and just medial to the anterior fibres of deltoid muscle.


Note. Both anterior and posterior borders of the clavicle give attachment to muscles: deltoid anteriorly and trapezius posteriorly.


The lateral end of the clavicle. This can be identified by a small tubercle on its superior surface which is palpable lying just medial to the acromioclavicular joint (see joints of the upper limb).




The scapula (Fig. 2.2)


The scapula [scapulae (L) = shoulder blades] (Fig. 2.2) is a flat triangular bone situated on the posterolateral aspect of the upper chest wall. It has three angles, three borders and costal and dorsal surfaces, the latter being marked by a ledge-shaped spine running almost horizontally.






The spine is wider laterally where it joins the acromion process, but narrows as it passes medially. Its upper and lower borders diverge as it meets the medial border forming a small smooth triangular area. Above the spine there is a deep hollow called the supraspinous fossa and below a larger but shallower depression called the infraspinous fossa.


The lateral angle is expanded and forms the glenoid cavity for articulation with the head of the humerus at the shoulder joint. It presents a sharp bony projection passing forward just below the lateral end of the clavicle. This is the coracoid process, which is roughened for the attachment of muscle.



Palpation




The spine of the scapula. The whole length of the spine can be palpated between the acromion process laterally and the medial border of the scapula. You will be able to recognize its upper and lower lips even though they give attachment to the trapezius and deltoid muscles, respectively. The posterior surface is easily visible and palpable. Notice that it is narrow medially but that it gradually broadens out as it passes laterally to become the superior surface of the acromion.


Note 1. At this point the spine is covered by a bursa (the supra-acromial bursa), enabling the skin to move easily over the bone.


Note 2. The bone then appears to form a large quadrilateral surface, which is directed upwards and slightly backwards having posterior, lateral and short anterior borders. On its medial side, the lateral end of the clavicle and the small gap produced by the acromioclavicular joint can be palpated. The smooth triangular area at the medial end of the spine is also covered by a bursa and can be palpated through the tendinous lower fibres of trapezius muscle.


The medial border of the scapula. The medial border of the scapula is approximately 5 cm lateral to the spines of the second to eighth thoracic vertebrae. Its full length can only be palpated with difficulty, except in lean subjects, as it gives attachment to levator scapulae above and rhomboid major and minor below, as well as being mostly covered by trapezius muscle.


The superior angle of the scapula. This is buried in muscle and is tender on deep palpation.


The inferior angle of the scapula. This can be identified lying on the posterolateral parts of the seventh and eighth ribs. Ask the model to raise the arm above the head. You will now be able to see and feel the inferior angle of the scapula moving laterally around the chest wall as far as the mid-axillary line.


The lateral border of the scapula. This is very difficult to palpate as it is embedded in thick muscle (teres major and minor).


Note. The lateral border of the scapula is by far the thickest of the borders and acts as a lever for its strong muscles to pull it laterally in scapula rotation.


The coracoid process of the scapula. This process can be palpated where it lies anteriorly, in the infraclavicular fossa, 3 cm below the junction of the lateral and middle thirds of the clavicle. This is in spite of the fact that it gives attachment to three muscles: the short head of the biceps, coracobrachialis and pectoralis minor. Care should be taken not to apply very deep pressure as this may elicit tenderness in some subjects.


The anterior rim of the glenoid cavity. The concave anterior rim of the glenoid cavity can be palpated just lateral to the coracoid process, running downwards and laterally for approximately 3 cm, with the head of the humerus lying on its lateral side.



Palpation on movement


Once you have been able to recognize the boundaries of the scapula by palpation of its various features, it is important to be able to follow its movements around the chest wall during activities of the shoulder girdle and upper limb.


For palpation in this area, the model should be in the standing or sitting position.



Protrusion. Place your right hand on the point of the model’s right shoulder. Now place your left hand on the inferior angle and the lower part of the medial border of the scapula. Ask the model to pull the shoulder girdles forward as in hunching the shoulders (protrusion). You will be able to see and palpate the scapula moving forwards around the chest wall whilst remaining in its vertical position.


Retraction. Ask the model to brace back the shoulder girdles. You will be able to see and palpate the scapula moving backwards, again not changing its vertical position.


Elevation and depression. Keep your hands in the same position. Ask the model to raise (elevation) and lower (depression) the shoulder girdles as in shrugging. You will be able to see and palpate the scapula rising and lowering but still holding its vertical position.


Lateral rotation. Ask the model to raise the right arm above the head. When the upper limb reaches 20°, you will be able to see and palpate the scapula rotating around an axis just below the spine nearer to its medial end. The superior angle will rise, moving medially, and the inferior angle will be observed, moving laterally and slightly upwards around the chest wall (lateral rotation). In fact, the inferior angle will reach as far as the mid-axillary line on full elevation of the humerus.


Medial rotation. Ask the model to lower the right arm from above the head. As the arm is lowered, you will be able to see and palpate the scapula returning to its original position (medial rotation). If, however, the arm is taken behind the back, medial rotation continues and the inferior angle will come close to the spines of the vertebrae.



Anatomy


Viewed from above and slightly laterally with the upper limb in about 45° of abduction, the shoulder girdle forms a ‘V’ shape with the clavicle being the anterior and the spine of the scapula the posterior stem. They form an angle with each other of approximately 70° and are joined at the acromioclavicular joint. The greater tuberosity of the humerus is now tucked underneath the arch of the acromion. Below the junction of the middle with the lateral third of the clavicle lies the coracoid process and below the lateral third of the clavicle lies the head of the humerus. The acromion appears quadrilateral from above and continues medially and backwards as the spine of the scapula. The upper third of the scapula lies above and anterior to the spine with the superior angle being most medial and the superior border passing laterally, presenting the suprascapular notch and continuing to the base of the coracoid process.


The anterior border of the lateral third of the clavicle continues laterally with the short anterior border of the acromion process. It continues as the lateral and posterior borders, becoming the inferior border of the spine.




Palpation on movement




Protraction. Place the fingers and thumb of your right hand on the medial end of the right clavicle. Now place the fingers and thumb of your left hand on the lateral end of the right clavicle. Ask the model to draw the shoulder girdle forward (protrusion). Palpate the lateral end of the clavicle as it moves forward, accompanied by the gliding of the scapula around the chest wall. Now palpate the medial end of the clavicle and note that it glides backwards in the clavicular notch of the sternum.


Note. The axis around which this movement occurs is approximately 3 cm from the medial end of the clavicle, where the costoclavicular ligament attaches to the undersurface of the bone.


Retraction. Ask the model to draw the shoulders backwards (retraction). Palpate the lateral end of the clavicle which will move backwards. Now palpate the medial end of the bone which will move forwards and become proud of the sternum.


Elevation. Ask the model to raise the shoulder girdle (elevation). Now palpate the lateral end of the clavicle which will rise. Palpate the medial end of the bone which will move down, rolling into the clavicular notch of the sternum using the same fulcrum as above.


Depression. Ask the model to lower the shoulder girdle. Now palpate the lateral end of the clavicle which will drop. If you palpate its medial end, you will feel this end of the bone rising to its original position. If you now ask the model to depress the shoulder girdle further, you will feel the medial end of the clavicle protruding upwards.


Elevation of the upper limb. Ask the model to raise the arm above the head. Now palpate the clavicle as, initially, it will move as in the movement of elevation. In the final stage of the movement, however, you will be able to feel the entire bone rotating with its anterior surface moving upwards. You will also be able to palpate the lateral rotation of the scapula which accompanies this movement. If the model now lowers the arm, the shoulder girdle will return to its original position.


Note. Movements of the clavicle, scapula and humerus and the joints between them are highly complex and should be studied in Anatomy and Human Movement (Palastanga et al 2002).




The elbow region (Fig. 2.3)


This region comprises the lower end of the humerus and the upper ends of the radius and ulna.






The lower end of the humerus is composed of a medial and lateral condyle, having two articular surfaces: the trochlea and the capitulum, respectively. Above these surfaces anteriorly are two fossae: the coronoid medially and radial laterally. Posteriorly, there is a larger depression: the olecranon fossa. On the lateral side of the lateral condyle is a prominence: the lateral epicondyle. This lies at the lower end of the lateral supracondylar ridge. The upper end of the radius is composed of a head which is button-shaped and articular on its upper surface, and the medial third of its rim. There is a neck, which is cylindrical, joining the head to the upper end of the shaft. There is also a large tuberosity (bicipital tuberosity), which projects from its medial side at the base of the neck. It is roughened on its posterior aspect for the attachment of the tendon of biceps brachii.



Palpation


For palpation in this area, the model should be in the sitting position.



The humerus. Find the lower attachment of deltoid muscle which is halfway down the lateral side of the arm. Just below this, you will be able to palpate the humerus.


Note. The humerus is crossed laterally by the radial nerve running downwards and forwards. Trauma in this area can cause pain, tingling and, sometimes, numbness of the posterolateral aspect of the hand.


The lateral supracondylar ridge of the humerus. Inferiorly, you will palpate a sharp border on the bone. This is the lateral supracondylar ridge which terminates at the large lateral epicondyle.


The lateral epicondyle of the humerus. You will be able to palpate the posterior surface of this epicondyle which is subcutaneous.


The olecranon fossa of the humerus. Ask the model to flex the elbow. Now you can trace the ridge medially across the back of the humerus to the commencement of the olecranon [olekranon (Gk) = the point of the elbow] fossa.


The head of the radius [radius (L) = spoke of a wheel]. Ask the model to extend the elbow. Now you will be able to palpate the lateral side of the button-shaped head of the radius situated immediately below the humeral epicondyle. The narrow groove running horizontally between the two is the radiohumeral part of the elbow joint.


The neck of the humerus. Palpate around the lateral half of the radial head, posteriorly, as far as the posterior aspect of the superior radioulnar joint. Just below the head, laterally, palpate the narrowed radial neck which is hidden by muscles anteriorly and posteriorly.


The olecranon process of the ulna (Fig. 2.3a, b). Ask the model to extend and then to flex the elbow. Now palpate the large bony formation of the olecranon, particularly when the elbow is flexed. Its superior surface is more difficult to feel because it is covered by the tendon of triceps as the tendon inserts into its posterior aspect.


The olecranon bursa. Now place your fingers on the posterior triangular surface of the olecranon. You will find that the skin and superficial fascia can easily be moved owing to the presence of the subcutaneous olecranon bursa.


Note. If pressure is applied for some time to this area, as in leaning on the elbows, the bursa can become inflamed and swollen (bursitis).


The medial and lateral surfaces of the olecranon process. Palpate the narrow triangular surface which has its apex downwards and is continuous with the posterior border of the ulna. Palpate this border which is subcutaneous as far as its head. Whilst you will be able to palpate the medial and lateral surfaces of the olecranon relatively easily, they are covered by muscle lower down and are more difficult to identify. The olecranon is much more difficult to palpate when the elbow is extended, as it moves into the olecranon fossa of the posterior surface of the distal end of the humerus.



On the medial surface of the medial condyle of the humerus there is a large projection: the medial epicondyle. This is slightly hollowed posteriorly. Above this is the medial supracondylar ridge which passes up to the medial side of the shaft.


The pulley-shaped trochlea is articular and covers the anterior, inferior and posterior aspect of the bone. Its medial flange is lower than the lateral and accounts for the angle at the elbow joint.


The upper end of the ulna, lying below the trochlea of the humerus, is composed mainly of a hook-shaped process: the olecranon. There is a shelf-like process projecting forwards from the upper end of the shaft: the coronoid process. The two form a socket shape facing forwards: the trochlear notch. This articulates with the trochlea of the humerus in the elbow joint.



Palpation




The medial supracondylar ridge of the humerus. On the medial side of the elbow, you will be able to palpate the sharp medial supracondylar ridge. Trace this ridge upwards for approximately the lower quarter of the humerus.


The medial epicondyle of the humerus. At the lower end of the medial supracondylar ridge, palpate a large, bony prominence 2 cm above the elbow joint and approximately 1 cm below the level of the lateral epicondyle. This is the medial epicondyle of the humerus, behind which there is a deep groove for the ulnar nerve.


Note. Palpation of this area may be quite tender and could cause tingling or even numbness on the medial side of the hand due to pressure on the ulnar nerve. This is often erroneously referred to as the ‘funny bone’, owing to the strange sensation when the nerve is compressed.


The olecranon fossa. Ask the model to flex the elbow joint fully. It is just possible to feel the depression of the olecranon fossa through the tendon of triceps.


The medial and lateral epicondyles of the humerus. From the posterior aspect, locate the medial and lateral epicondyles.


The olecranon process of the ulna. At a point midway between the two epicondyles, press your thumb onto the back of the triceps tendon. You will observe that the tendon will sink slightly into the olecranon fossa. Just below your thumb you will palpate the bony olecranon.


The coronoid process of the ulna (coronoid [corone (Gk) = crown; also the name given to the pointed front of a ship or plough]). Ask the model to extend the right elbow joint and and fully supinate the forearm. With the forearm in this fully extended position, examine the anterior aspect of this region. Place the flat surface of your right hand 2.5 cm below and 2.5 cm lateral to the medial epicondyle of the humerus. You will feel a hard bony projection deep to the mass of the flexor muscles. This is the coronoid process of the ulna.




The wrist and hand


The lower ends of the radius and ulna form a shallow mortice into which three of the four bones of the proximal row of carpals – scaphoid, lunate and triquetral – fit. The fourth bone in the proximal row, the pisiform, lies anterior to the triquetral. Distally, the proximal row of carpal bones form another concavity for the reception of the second row of carpal bones: the trapezium, trapezoid, capitate [capitate (L) = head-shaped] and hamate. The capitate is the largest of the four and fits snugly into the deepest part of the concavity, being in contact with all the carpal bones except the pisiform, triquetral and trapezium (Fig. 2.4b).


The metacarpals are miniature long bones lying distal to the carpals. The metacarpal of the thumb articulates with the trapezium; the second mainly articulates with the trapezoid; that for the middle finger mainly articulates with the capitate and the fourth and fifth articulate with the hamate.


Each metacarpal head articulates with a proximal phalanx. Each finger has a middle and a distal phalanx, the thumb has only a distal phalanx.



Anterior, medial and lateral aspects




Palpation


The bones of the wrist and hand are more difficult to locate on the anterior surface as they tend to be hidden by the muscles which arise and insert in the hand.


For palpation in this region, the model should be in the sitting position with the forearm resting on a pillow or an alternative support.



The triquetral bone [triquetrus (L) = having three corners]. Return to the wrist joint. Locate the head of the ulna on its medial side (Fig. 2.4). Immediately distal to this, palpate the medial and posterior surfaces of the triquetral bone.


The pisiform bone [pisum (L) = a pea]. On the anterior surface of the triquetral bone, palpate the pea-shaped pisiform bone. This bone is easily recognizable owing to its prominence and by the attachment of the tendon of flexor carpi ulnaris to its proximal side.


Note. Application of deep pressure on the pisiform bone may elicit tenderness.


The hook of the hamate bone [hamatus (L) = hooked]. If you now apply relatively deep pressure with the tip of your thumb 1 cm distal and slightly lateral to the pisiform bone, you will be able to feel a small but distinct bony prominence. This is the hook of the hamate bone. Now move your thumb from side to side and palpate two small nerves: the superficial terminal branches of the ulnar nerve. These can be compressed against the prominent hook of the hamate.


The tip of the radial styloid process. On the lateral side of the wrist, locate the tip of the radial styloid process. It lies within a space termed the ‘anatomical snuff box’.


The anterior border of the radius. From the styloid process, trace upwards for a short distance and palpate the sharp anterior border of the radial shaft. The radial artery lies just medial to the crest of the anterior border.


The scaphoid bone [skaphe (Gk) = a skiff] and the trapezium [trapezion (Gk) = an irregular four-sided figure]. Distal to the styloid process of the radius, palpate the lateral surfaces of the scaphoid and trapezium bones.


The first metacarpal bone and its proximal and distal phalanges. The first metacarpal bone is identified by a small tubercle. Its shaft leads distally to its head. You should find the base, shaft and the head of the proximal phalanx easy to palpate. The base and shaft as far as the nail of the distal phalanx [phalanx (Gk) = a band of soldiers] are equally identifiable.


Note. The posterior surface of the bones of the thumb face laterally due to the thumb lying at right angles to the palm. Medially, the anterior surfaces are difficult to palpate due to the presence of muscle and tendon.


The tubercle of the scaphoid bone. To facilitate palpation of the tubercle of the scaphoid bone, ask the model to extend the wrist. The tubercle should then be palpable at the proximal end of the thenar eminence, on the front of the carpal region, 1 cm medial to the tip of the radial styloid process.


The vertical edge of the trapezium bone. If you apply deep pressure, the vertical ridge of the trapezium is just palpable 1 cm distal to the scaphoid tubercle.


Note 1. This can often be a painful area for deep palpation so it is advisable to limit the number of times this technique is performed.


Note 2. The scaphoid tubercle is prominent enough to be damaged by falls on the outstretched hand leading to a fracture. This is likely to cause pain and dysfunction of the hand for many months due to its poor blood supply leading to a long healing time.


The second–fifth metacarpal and phalangeal bones. The anterior surfaces of these remaining bones are difficult to palpate as they lie deep to the muscle and fascia. To facilitate palpation, ask the model to extend the fingers fully. The anterior surfaces of the heads of the metacarpals can be felt in line with each finger, 2 cm proximal to the web between the fingers. Ask the model to extend/hyperextend the metacarpophalangeal joints. Now palpate the heads of each phalanx, just proximal to the creases of the interphalangeal joints. If you now grip the lateral sides of the heads between your finger and thumb, you should be able to palpate a small tubercle situated on each side.





Posterior aspect (Fig. 2.5)






Palpation




The styloid process of the ulna. Place your finger on the button-shaped head of the ulna. This is clearly palpable posteromedially, but is hidden by the tendon of flexor carpi ulnaris anteriorly. Palpate the ulna styloid process as a small projection on its posteromedial aspect, although this may be difficult as the bone is partially hidden by the tendon of extensor carpi ulnaris muscle. To facilitate palpation, ask the model to deviate the wrist radially. You will find that the head of the ulna and its styloid process become much easier to identify.


The styloid process of the radius. Palpate the radial styloid process situated on the lateral side of the wrist, having tendons running in front and behind.


The lateral side of the lower half of the radius. From the styloid process, trace upwards and palpate the lower half of the lateral side of the radius. From here, palpation becomes more difficult because the bone is covered by the bulk of brachioradialis muscle.


Note. This region may be quite tender to palpate as it is often crossed by the superficial terminal branch(es) of the radial nerve.


The dorsal tubercle of the radius. On the posterior aspect of the distal end of the radius, just above the level of the styloid process, the dorsal tubercle of the radius can be palpated. The tendon of extensor pollicis longus muscle grooves its medial side and uses it as a pulley.


The posterior surfaces of the scaphoid, lunate [luna (L) = the moon] and triquetral bones. Find the dorsal tubercle of the radius. Below the level of this tubercle and the head of the ulna, locate a hollow; this is limited 2 cm below by the bases of the metacarpal bones. Ask the model to flex the wrist joint. Now palpate the posterior surfaces of the scaphoid, lunate and triquetral bones. They form a line distal to the tips of the radial and ulnar styloid processes.


The trapezoid, capitate and hamate bones. Move your fingers just distal to the previous line of bones. Grip the bones between your fingers posteriorly and your thumb anteriorly. Just beyond them, palpate the trapezoid bone, which is situated at the base of the second metacarpal. Now palpate the capitate bone, situated at the base of the third metacarpal. Lastly, palpate the hamate, situated at the base of the fourth and fifth metacarpal bones.


The second–fifth metacarpal and phalangeal bones. The lower limit of this area is marked by the bases of the metacarpal bones with their shafts running distally to end in rounded heads, all of which are easily palpable. To facilitate palpation, ask the model to flex the fingers. The base, shaft and head of each phalanx are now equally easy to palpate posteriorly. Anteriorly, they are hidden by tendons and the pulp of the fingers.





Joints



Joints of the pectoral girdle



The sternoclavicular joint (Fig. 2.6)


At its medial end the clavicle articulates with the clavicular notch of the manubrium sterni. The joint is synovial, being surrounded by a capsule lined with synovial membrane, except where it is attached to the edges of a fibrous disc which divides the joint space into two separate cavities. It is a modified saddle (sellar) joint and its capsule is supported by ligaments, the intercostal above and medially, the costoclavicular laterally below the clavicle and the anterior and posterior across the front and back of the joint. It is subcutaneous, allowing easy palpation of the joint line and a reasonable examination of joint movement.






Palpation on movement




Jun 11, 2016 | Posted by in ANATOMY | Comments Off on The upper limb
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