Veins of the Upper Limb
Veins of the upper limb extremities are grouped into deep veins which are accompanying veins of arteries from which they derive their names (Latin: vena comitantes), and superficial veins. Both groups of veins interconnect with one another and return blood from all parts of the upper limb to other veins of the thorax which finally drains into the heart. In the following paragraphs, each of these groups of veins is described in relation to parts of the upper limb they drain, as well as any of their clinical relevance. It is also important to note that in describing the veins of the upper limb, an opposite fashion to discussing the arterial supply of the upper limbs is employed. Thus while arteries are described based on how they course from the heart to the upper limbs, veins re described from their anastomoses in the digits of the hand up through the forearm, axilla to the heart.
There are two prominent superficial veins of the upper limb; they are the cephalic and basilic veins, and these two extensive veins originate from the venous networks of the dorsum of the hand.
The hand is drained by superficial and deep veins. In the palm, these veins form “arches” and they are associated with the superficial and deep palmar (arterial) arches, hence they are called superficial and deep venous palmar arches. In the dorsum of the hand are digital (phalangeal) and metarcarpal veins which anastomose with each other to form networks. The dorsal digital veins drain into three dorsal metarcarpal veins, which unite to form a dorsal venous network. Superficial to the metarcarpus, this network unites to give rise to two extensive superficial veins, the cephalic and basilic veins. On the lateral side of the carpus in a region called the anatomical snuffbox, the dorsal venous network is prolonged proximally as the cephalic vein, while the basilica vein arises from the medial side.
Relatively, little amount of blood is drained from the hand into the deep veins of the forearm. Most of the blood from the palm of the hand passes through to the venous network on the dorsum. All of the superficial veins of the hand drain into the cephalic and basilic veins.
ForearmThe forearm is drained by numerous deep veins which form double venae comitantes with arteries of the forearm. These deep veins of the forearm anatomoses freely with each other and return blood from the forearm with little contribution (little blood volume) from the hand.
The cephalic and basilic veins are major superficial veins of the forearm. From the radial side (lateral side) of the forearm, the cephalic vein runs up, from the anatomical snuffbox, along the preaxial border of the upper limb. It runs in the upper arm lateral to the biceps, in the deltopectoral groove, and perforates the clavipectoral fascia to drain into the axillary vein. From the ulnar side (medial side of forearm) the basilica vein runs up the postaxial border of the upper limb, pierces the deep fascia halfway between the elbow and axilla, and joins the brachial veins to form the axillary veins.
A third important superficial vein of the forearm is the median forearm vein (or median antebrachial vein). It drains subcutaneous tissue of the anterior part of the wrist and forearm. It bifurcates at the elbow (approximately within the cubital fossa) into the median cephalic and median basilic veins (producing an “M” formation of cubital veins). The latter receives a deep vein of the forearm. These two branches of the median forearm vein open into the cephalic and basilic veins respectively. The deep vein which communicates with the median basilic vein makes it a larger vessel than the median cephalic. The median cephalic is much less movable in the subcutaneous tissue than the median basilica, and is therefore is often more convenient to use in intravenous therapy in spite of its smaller size, although variations exist among individuals.
Like in the forearm, the arm is drained by the brachial veins (deep veins that accompany the brachial artery) and all its branches. In addition, the basilic and cephalic veins course upwards through the subcutaneous tissue and drain the superficial regions of the arm. The basilic veins perforate the deep fascia in the middle of the arm, while the cephalic lies in the groove between the deltoid and pectoralis major muscles, and ends by piercing the clavipectoral fascia to enter the axillary vein.
This is the space between the upper arm and the side of the thorax, bounded in front and behind by the axillary folds, communicating above with the posterior triangle of the neck and containing neurovascular structures, including lymph nodes, for the upper limb and the side wall of the thorax.
The vein formed in this space, the axillary vein ultimately returns blood from the upper limb through the superficial and deep veins of the arm. The venae comitantes of the brachial artery (i.e., the deep veins of the arm or brachial veins) are joined by the basilica vein above the lower border of the posterior wall of the axilla to form the axillary vein. There are three parts of the axillary vein, the first distal part into which the cephalic vein enters (at a point just superior to the pectoralis minor muscle), and the second and third parts, which give off branches corresponding to the tributaries off the axillary artery. The axillary vein courses upwards on the medial side of the axillary artery and leaves the axilla by passing through its apex anterior to the third part of the subclavian artery. Over the upper surface of the first rib, in front of scalenous anterior muscle, the axillary vein continues as the subclavian vein.
Venipuncture and Variation of Veins in the Cubital Fossa
The cubital fossa is the common site for sampling and transfusion of blood and intravenous injections because of the prominence and accessibility of veins. Usually, the median cubital vein or the basilic vein is selected. The median cubital vein lies directly on the deep fascia, crossing the bicipital aponeurosis, which separates it from the underlying brachial artery and median vein, and provides protection to the latter. Historically, during the days of bloodletting, the bicipital aponeurosis was known as the grace Deux (Fr. Grace of God) tendon, by the grace of which arterial haemorrhage was usually avoided. A tourniquet is placed around the mid-arm to distend the veins around the cubital fossa. Once the vein is punctured, the tourniquet is removed so that when the needle is removed the vein will not bleed extensively. The cubital veins are also a site for the introduction of cardiac catheters to secure blood samples from the great vessels and chambers of the heart. These veins may also be used for cardioangiography. The pattern of veins in the cubital fossa varies greatly. In approximately 20% of people, the median antebrachial vein (median vein of the forearm) divides into a median basilic vein, which joins the basilic vein, and a median cephalic vein which joins the cephalic vein. In these cases, a clear M formation is produced by the cubital veins. It is important to observe and remember that either the median cubital vein or the median basilic vein, which ever pattern is present, crosses superficial to the brachial artery, from which it is separated by the bicipital aponeurosis. These veins are good sites for drawing blood but are not ideal for injecting an irritating drug because of the danger of injecting it into the brachial artery. In obese people, a considerable amount of fatty tissue may overlie the vein.
Injuries to the Axillary Vein
Wounds in the axilla often involve the axillary vein because of its large size and exposed position. When the arm is fully abducted, the axillary vein overlaps the axillary artery anteriorly. A wound in the proximal part of the axillary vein is particularly dangerous, not only because of profuse bleeding but also because of the risk of air entering it and producing air emboli (air bubbles) in the blood.