Lab 13 Pre-Lab Exercise:
1. Visualizing the positions of the arteries
Peripheral pulses can be felt at six locations in the upper limb:
Axillary pulse: axillary artery in the axilla lateral to the apex of the dome of skin covering the floor of the axilla.
Brachial pulse (mid-arm): 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.
Brachial pulse (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 blood pressure reading. The biceps brachii should be relaxed; otherwise the bicipital apeoneurosis will prevent easy palpation.
Radial pulse (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.
Radial pulse (anatomical snuffbox): radial artery as it crosses the lateral side of the wrist between the tendon to the extensor pollicis longus muscle and the tendons of the extensor pollicis brevis and abductor pollicis longus muscles.
Ulnar pulse: ulnar artery immediately under the lateral margin of the flexor carpi ulnaris tendon and proximal to the pisiform.
The positions of the superficial and deep palmar arches in the hand can be visualized using bony landmarks, muscle eminences, and skin ceases. The superficial palmar arch begins as a continuation of the ulnar artery, which lies lateral to the pisiform bone. 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 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 the metacarpals 1 and 2. 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 ½ of the distance between the distal wrist crease and the proximal transverse crease of the palm.
2. Visualizing the positions of the veins
Deep veins lie internal to the deep fascia and occur as paired, continually anastomosing accompanying veins surrounding and sharing the name of the artery they accompany. Perforating veins penetrate the deep fascia and blood is continuously shunted from superficial veins in the subcutaneous tissue to the deep veins via these perforating veins.
Because of the prominence and accessibility of the superficial veins, they are commonly used for venipuncture (puncture of a vein to draw blood or inject a solution). The median cubital vein the most commonly used. The veins forming the dorsal venous network of the hand and the cephalic and basilic veins arising from it are commonly used for long-term introduction of fluids (intravenous feeding).