4 Neurovascular Systems: Forms and Relations
4.1 The Arteries
A Different segments of the arteries of the lower limb
a Right leg, anterior view; b right leg, posterior view. The different arterial segments are shown in different colors.
External iliac artery arises with the internal iliac artery from the common iliac artery and descends along the medial border of the psoas major through the lacuna vasorum (see p. 555). It becomes the femoral artery at the level of the inguinal ligament.
Femoral artery, the continuation of the external iliac artery, runs down the medial side of the thigh to the adductor canal, through which it passes from the anterior to the posterior side of the limb. On leaving the adductor hiatus, it becomes the popliteal artery.
Popliteal artery runs from the adductor hiatus through the popliteal fossa to the popliteus, dividing at the inferior border of that muscle into its terminal branches, the anterior and posterior tibial arteries. Anterior tibial artery enters the extensor compartment of the leg at the upper border of the interosseous membrane and descends between the tibialis anterior and extensor hallucis longus. Distal to the extensor retinaculum, it continues onto the dorsum of the foot as the dorsal pedal artery.
Posterior tibial artery, the direct continuation of the popliteal artery, enters the flexor compartment of the leg and passes behind the medial malleolus. At that level it divides into its two terminal branches, the medial and lateral plantar arteries (the latter is shown in D), which continue onto the plantar side of the foot. The posterior tibial artery also gives rise to the fibular artery.
B Overview of the principal arteries of the lower limb
The arteries of the lower limb vary considerably in their origins and branching patterns (the main variants are reviewed in Chapter 5, Neurovascular Systems: Topographical Anatomy). The branches are listed in the order in which they arise from the parent vessels.
Branches of the external iliac artery
• Inferior epigastric artery
– Cremasteric artery
– Artery of the round ligament of the uterus
– Pubic branch
• Deep circumflex iliac artery
Branches of the femoral* artery
• Superficial epigastric artery
• Superficial circumflex iliac artery
• Superficial external pudendal artery
• Deep external pudendal artery
• Deep artery of the thigh
– Medial circumflex femoral artery
– Lateral circumflex femoral artery
– Perforating branches
• Descending genicular artery
Branches of the popliteal artery
• Posterior tibial recurrent artery (arterial network of the knee)
• Medial and lateral superior genicular arteries (arterial plexus, which runs mainly on the front of the knee)
• Sural arteries
• Middle genicular artery
• Medial and lateral inferior genicular arteries
Note that the paired superior and inferior genicular arteries form the arterial anastomotic network around the knee.
Branches of the anterior tibial artery
• Anterior tibial recurrent artery
• Anterior lateral malleolar artery
• Anterior medial malleolar artery
• Dorsal pedal artery
– Lateral tarsal artery
– Medial tarsal artery
– Arcuate artery with the dorsal metatarsal arteries (→ dorsal digital arteries)
Branches of the posterior tibial artery
• Fibular artery
– Perforating branch
– Communicating branch
– Lateral malleolar branches
– Calcaneal branches
• Medial malleolar branch
• Calcaneal branches
• Medial plantar artery
– Superficial branch
– Deep branch (→ deep plantar arch)
• Lateral plantar artery (→ deep plantar arch)
• Plantar metatarsal arteries
• Common plantar digital arteries
* Often referred to clinically as the superficial femoral artery.
→ = is continuous with
Note: In addition, the lower limb is supplied by branches of the internal iliac artery (e.g., the obturator artery).
D The arteries of the sole of the foot
Right foot, plantar view.
E The arteries of the popliteal fossa and leg
Right leg, posterior view.
4.2 The Veins
A The deep and superficial veins of the right lower limb
a Thigh, leg, and dorsum of the foot, anterior view.
b Leg, posterior view.
c Sole of the foot, plantar view.
For clarity, only the most important veins are demonstrated here.
B Overview of the principal veins of the lower limb
The veins of the lower limb are subdivided into three systems: a superficial (epifascial) system, a deep (intermuscular) system, and a perforating system that interconnects the superficial and deep veins. The upright human body posture places an exceptional load on the veins of the lower limb, which must act against the force of gravity in returning the blood to the heart (the deep venous system handles approximately 85% of the venous return, the superficial veins approximately 15%). A series of venous valves help to maintain the normal superficial-to-deep direction of blood flow (compare E). Note that, for the sake of clarity, not all of the veins in the table below have been depicted in these illustrations.
Deep veins of the lower limb
• Femoral vein
• Deep vein of thigh
• Medial and lateral circumflex femoral veins
• Popliteal vein
• Sural veins
• Genicular veins
• Anterior and posterior tibial veins
• Fibular veins
• Dorsal and plantar metatarsal veins (see Ac)
• Plantar digital veins (see Ac)
Superficial lower limb veins
• Great saphenous vein
• External pudendal veins
• Superficial circumflex iliac vein
• Superficial epigastric vein
• Accessory saphenous vein
• Posterior arch vein
• Small saphenous vein (see Cb)
• Femoropopliteal vein (see Cb)
• Dorsal venous network (see Ca)
• Dorsal venous arch
• Plantar venous network
• Plantar venous arch
Of the many perforating veins in the leg, three groups have the greatest clinical importance (see E):
• The Dodd group
(medial side of the thigh, middle third)
• The Boyd group
(medial side of the leg below the knee)
• The Cockett group
(medial side of the distal leg)
C Superficial (epifascial) veins of the right lower limb
a Thigh, leg, and dorsum of the foot, anterior view.
b Leg, posterior view.
D Varices of the superficial leg veins
a Spider veins (tiny intradermal varices).
b Reticular varices (weblike dilations of small subcutaneous veins).
c Great saphenous varicosity.
d Small saphenous varicosity.
Varicose disease of the superficial leg veins is the most common chronic venous disease, affecting 15% of the adult population. Varicose veins can be classified as primary idiopathic varices (75%) or as secondary symptomatic varices. Primary varices generally result from degeneration of the vein wall leading to incompetence of the venous valves. Secondary varices result from chronic occlusion of the deep venous system with incompetence of the perforator veins and a reversal in the direction of venous flow. Besides chronic conditions, there are also important acute diseases that may affect the superficial venous system (e.g., thrombophlebitis) and deep venous system (e.g., venous thrombosis).
E Clinically important perforating veins
Right leg, medial view. Numerous perforating veins interconnect the deep and superficial venous systems of the leg. Their venous valves normally prevent blood flow from the deep veins to the superficial cutaneous veins. The clinically important members of this system are located between the deep veins and the tributary region of the great saphenous vein:
• Dodd veins: located between the great saphenous vein and femoral vein at the level of the adductor canal.
• Boyd veins: located between the great saphenous vein and posterior tibial veins on the medial side of the proximal leg.
• Cockett veins (I–III): located between a curved branch of the great saphenous vein behind the medial malleolus (the posterior arch vein) and the posterior tibial veins. The Cockett veins on the medial side of the distal leg are of special clinical importance because of this region’s susceptibility to ulceration.
4.3 The Lymphatic Vessels and Lymph Nodes
A The superficial lymphatic system of the right lower limb
a Anterior view, b posterior view. (The arrows indicate the main directions of lymphatic drainage.)
The lymph in the lower limb is drained by a superficial (epifascial) system and a deep (subfascial) system, similar to the arrangement in the arm. The largest lymph vessels, called collectors, basically follow the course of the superficial veins (great and small saphenous veins) and deep veins (popliteal vein, femoral vein) and are interconnected by anastomoses located mostly in the popliteal and inguinal regions. While the superficial lymph vessels primarily drain the skin and subcutaneous tissue, the deep system drains lymph from the muscles, joints, and nerves. The superficial lymphatics consist of an anteromedial bundle and a posterolateral bundle. The anteromedial bundle runs along the great saphenous vein to the superficial inguinal lymph nodes. It drains all of the skin and subcutaneous tissue of the lower limb except for the lateral border of the foot and a narrow strip on the calf. Those areas are drained by the posterolateral bundle (see b), which thus receives drainage from a considerably smaller region. The lymph in the posterolateral bundle first passes along the small saphenous vein to the superficial popliteal lymph nodes and then drains through the deep popliteal lymph nodes to the deep inguinal lymph nodes.
B The deep lymph nodes of the inguinal region
Right inguinal region after removal of the cribriform fascia about the saphenous opening, anterior view. The veins and lymphatic system above the inguinal ligament are shown in light shading. The deep inguinal lymph nodes are located near the termination of the great saphenous vein, medial to the femoral vein. They are important because all the lymph from the limb filters through them before reaching the iliac lymph nodes. The largest lymph node of this group (Rosenmüller’s lymph node) is also the highest, placed at the level of the femoral canal. The group of pelvic lymph nodes, which includes the external iliac nodes, begins just above the inguinal ligament.