Anatomy
of the venous system in the limbs
Arterial blood flows through the main axial arteries to the upper and
lower limbs. It returns via the deep and superficial veins. In the upper limb
the superficial veins are more important in carrying blood back to the heart.
In the lower limb, the superficial veins carry only about 10 per cent of the
blood, while the remainder passes via the deep veins. The superficial veins lie
superficial to the muscle fascia of the limb. The principal superficial veins in
the leg are the long and short saphenous veins (Fig. 16.1). In the arm, the
cephalic and basilic veins are the principal superficial veins.
Interestingly,
venous diseases occur much more frequently in the lower limb than in the upper
limb, and most often in the superficial veins. The deep veins of the lower limb
may be
the site of life-threatening venous thrombosis or venous valvular
incompetence resulting in leg ulceration. Each major axial artery has at least
one and often a pair of accompanying veins named after the artery (Fig.
16.2).
The superficial and deep veins join at a number of points. The short saphenous
vein terminates at the saphenopopliteal junction (SPJ) and the long saphenous
vein at the saphenofemoral junction (SFJ) in the groin. Here the flow in the
superficial veins joins that in the deep veins. There is, in addition, a number
of places in the calf and thigh where flow in the superficial veins may also
join that in the deep veins. These is the ankle, calf and thigh communicating or
perforating veins (Fig. 16.3). The names
of these veins come from their course from the superficial to the deep
venous system in which they perforate the deep fascia of the leg. Near the ankle
are the Cockett perforating veins, near the knee the Boyd perforators and in the
thigh the Hunterian perforating vein. All veins in the upper and lower limbs
contain valves every few centimetres which ensure that blood flows towards the
heart.