Superficial Anatomy of the UL PDF

Surface Anatomy of the Upper Limb DPM Program 1. Identify the surface anatomy and palpable bony landmarks of the upper extremity. 4.0 2. Identify sites where pulses are taken in the upper extremity. 4.0 1 Bony Landmarks and Muscles of the Posterior Scapular Region The medial border, inferior angle,...

Surface Anatomy of the Upper Limb DPM Program 1. Identify the surface anatomy and palpable bony landmarks of the upper extremity. 4.0 2. Identify sites where pulses are taken in the upper extremity. 4.0 1 Bony Landmarks and Muscles of the Posterior Scapular Region The medial border, inferior angle, and part of the lateral border of the scapula can be palpated on a patient, as can the spine and acromion. The superior border and angle of the scapula are deep to soft tissue and are not readily palpable. The supraspinatus and infraspinatus muscles can be palpated above and below the spine, respectively The trapezius muscle is responsible for the smooth contour of the lateral side of the neck and over the superior aspect of the shoulder. The deltoid muscles form the muscular eminence inferior to the acromion and around the glenohumeral joint. The axillary nerve passes posteriorly around the surgical neck of the humerus deep to the deltoid muscle. The latissimus dorsi muscle forms much of the muscle mass underlying the posterior axillary skin fold extending obliquely upward from the trunk to the arm. The teres major muscle passes from the inferior angle of the scapula to the upper humerus and contributes to this posterior axillary skin fold laterally. 2 3 Brachial Artery The brachial artery is on the medial side of the arm in the cleft between the biceps brachii and triceps brachii muscles. The median nerve courses with the brachial artery, whereas the ulnar nerve deviates posteriorly from the vessel in distal regions. 4 Posterior Arm & Forearm Superficial Anatomy The triceps brachii muscle forms the soft tissue mass posterior to the humerus, and the tendon inserts onto the olecranon of the ulna, which is readily palpable and forms the bony protuberance at the “tip” of the elbow The brachioradialis muscle is also visible as a muscular bulge on the lateral aspect of the arm. It is particularly prominent when the forearm is half pronated, flexed at the elbow against resistance, and viewed anteriorly. The radial nerve in the distal arm emerges from behind the humerus to lie deep to the brachioradialis muscle. 5 Tendons, Major Vessels, and Nerves in the Distal Forearm In the anterior aspect of the distal forearm, the tendons of the flexor carpi radialis, flexor carpi ulnaris, and palmaris longus muscles can be easily located either by palpating or by asking a patient to flex the wrist against resistance. 1.The tendon of flexor carpi radialis is located approximately at the junction between the lateral and middle thirds of an imaginary line drawn transversely across the distal forearm. The radial artery is immediately lateral to this tendon and this site is used for taking a radial pulse. 2.The tendon of the flexor carpi ulnaris is easily palpated along the medial margin of the forearm and inserts on the pisiform, which can also be palpated by following the tendon to the base of the hypothenar eminence of the hand. The ulnar artery and ulnar nerve travel through the distal forearm and into the hand under the lateral lip of the flexor carpi ulnaris tendon and lateral to the pisiform. 3.The palmaris longus tendon may be absent, but when present, lies medial to the flexor carpi radialis tendon and is particularly prominent when the wrist is flexed against resistance. The median nerve is also medial to the flexor carpi radialis tendon and lies under the palmaris longus tendon. 4.The long tendons of the digits of the hand are deep to the median nerve and between the long flexors of the wrist. Their position can be visualized by rapidly and repeatedly flexing and extending the fingers from medial to lateral. 5.In the posterior distal forearm and wrist, the tendons of the extensor digitorum are in the midline and radiate into the index, middle, ring, and little fingers from the wrist. 6.The distal ends of the tendons of the extensor carpi radialis longus and brevis muscles are on the lateral side of the wrist and can be accentuated by making a tight fist and extending the wrist against resistance. 7.The tendon of the extensor carpi ulnaris can be felt on the far medial side of the wrist between the distal end of the ulna and the wrist. 8.Hyperextension and abduction of the thumb reveals the anatomical snuffbox. The medial margin of this triangular area is the tendon of the extensor pollicis longus, which swings around the dorsal tubercle of the radius and then travels into the thumb. The lateral margin is formed by the tendons of the extensor pollicis brevis and abductor pollicis longus. The radial artery passes through the anatomical snuffbox when traveling laterally around the wrist to reach the back of the hand and penetrate the base of the first dorsal interosseous muscle to access the deep aspect of the palm of the hand. The pulse of the radial artery can be felt in the floor of the anatomical snuffbox in the relaxed wrist. The cephalic vein crosses the roof of the anatomical snuffbox, and cutaneous branches of the radial nerve can be felt by moving a finger back and forth along the tendon of the extensor pollicis longus muscle. 6 7 Normal Appearance of the Hand In the resting position, the palm and digits of the hand have a characteristic appearance. The fingers form a flexed arcade, with the little finger flexed the most and the index finger flexed the least. The pad of the thumb is positioned at a 90° angle to the pads of the fingers. A thenar eminence occurs at the base of the thumb and is formed by the underlying thenar muscles. A similar hypothenar eminence occurs along the medial margin of the palm at the base of the little finger. The appearance of the thenar and hypothenar eminences, and the positions of the fingers change when the ulnar and median nerves are compromised. Major superficial veins of the upper limb begin in the hand from a dorsal venous network, which overlies the metacarpals. The basilic vein originates from the medial side of the network and the cephalic vein originates from the lateral side 8 Flexor Retinaculum The proximal margin of the flexor retinaculum can be determined using two bony landmarks. 1.The pisiform bone is readily palpable at the distal end of the flexor carpi ulnaris tendon. 2.The tubercle of the scaphoid can be palpated at the distal end of the flexor carpi radialis tendon as it enters the wrist An imaginary line between these two points marks the proximal margin of the flexor retinaculum. The distal margin of the flexor retinaculum is approximately deep to the point where the anterior margin of the thenar eminence meets the hypothenar eminence near the base of the palm. The recurrent branch of the median nerve lies deep to the skin and deep fascia overlying the anterior margin of the thenar eminence near the midline of the palm. 9 The superficial palmar arch begins as a continuation of the ulnar artery, which lies lateral to the pisiform bone at the wrist. The arch curves laterally across the palm anterior to the long flexor tendons in the hand. The arch reaches as high as the proximal transverse skin crease of the palm and terminates laterally by joining a vessel of variable size, which crosses the thenar eminence from the radial artery in the distal forearm. The deep palmar arch originates on the lateral side of the palm deep to the long flexor tendons and between the proximal ends of metacarpals I and II. It arches medially across the palm and terminates by joining the deep branch of the ulnar artery, which passes through the base of the hypothenar muscles and between the pisiform and hook of the hamate. The deep palmar arch is more proximal in the hand than the superficial palmar arch and lies approximately one-half of the distance between the distal wrist crease and the proximal transverse skin crease of the palm. 10 Peripheral pulses can be felt at six locations in the upper limb: 1.Axillary pulse: axillary artery in the axilla lateral to the apex of the dome of skin covering the floor of the axilla. 2.Brachial pulse in midarm: brachial artery on the medial side of the arm in the cleft between the biceps brachii and triceps brachii muscles. This is the position where a blood pressure cuff is placed. 3.Brachial pulse in the cubital fossa: brachial artery medial to the tendon of the biceps brachii muscle. This is the position where a stethoscope is placed to hear the pulse of the vessel when taking a blood pressure reading. 4.Radial pulse in the distal forearm: radial artery immediately lateral to the tendon of the flexor carpi radialis muscle. This is the most common site for “taking a pulse.” 5.Ulnar pulse in the distal forearm: ulnar artery immediately under the lateral margin of the flexor carpi ulnaris tendon and proximal to the pisiform. 6.Radial pulse in the anatomical snuffbox: radial artery as it crosses the lateral side of the wrist between the tendon of the extensor pollicis longus muscle and the tendons of the extensor pollicis brevis and abductor pollicis longus muscles 11 12