The cephalic vein is a superficial vein of the upper limb. Its name derives from ‘cephalic’ meaning head, as the vein runs up to the shoulder. The superficial venous network is the source of blood for most blood tests, and is the easiest place to access venous blood. In this article we will discuss the anatomy and clinical relevance of the cephalic vein.
The cephalic vein is a superficial vein of the hand, forearm and arm. Between the superficial and deep networks of veins, are valves that reduce the likelihood of backflow from the deep venous system.
The cephalic vein drains the dorsal venous network of the hand that crosses the anatomical snuffbox, runs superficial to the radial styloid process and then ascends in the superficial fascia of the forearm. The cephalic vein then communicates with the basilic vein at the cubital fossa, via the median cubital vein. At this point the vein lies superficially in the lateral part of the elbow joint crease.
The cephalic vein now runs along the groove between the brachioradialis (elbow flexor and forearm supinator) and biceps brachii (forearm supinator and elbow flexor) muscles. The vein continues to ascend in the superficial fascia anterolateral to biceps brachii and superficial to the lateral cutaneous nerve of the forearm, which is a sensory branch of the musculocutaneous nerve (ventral rami of C5-7) that innervates the muscles of the anterior compartment of the arm. The cephalic vein continues to ascend in a groove between the pectoralis major and deltoid muscles. The deltoid branch of the thoracoacromial trunk accompanies the cephalic vein in this region.
It crosses the clavipectoral fascia and axillary artery to drain into the axillary vein below the clavicle. The axillary vein is renamed the subclavian vein once it passes the lateral border of the first rib, and the subclavian vein unites with the internal jugular vein to form the brachiocephalic vein.
The thoracic duct drains lymph from the lower limbs, pelvis, abdomen, left thorax, left upper limb and left side of the head and neck and drains into the angle between the left jugular vein and the subclavian vein on the left hand side. The lymphatic drainage of the right upper limb, right thorax and right side of the head and neck empties into the junction between the right subclavian vein and internal jugular vein, which merge to form the right brachiocephalic vein. The two brachiocephalic veins unite to form the superior vena cava that drains into the right atrium of the heart.