Human Anatomy and Physiology - N. I. Fedyukovich 2003

Cardiovascular System
Veins of the Systemic Circulation
Inferior Vena Cava System

The INFERIOR VENA CAVA system is formed by Veins that collect Blood from the lower extremities, as well as the walls and Organs of the pelvis and Abdominal cavity.

The inferior vena cava is formed by the confluence of the left and right common iliac veins. This thickest venous trunk is located retroperitoneally. It originates at the level of the IV–V lumbar vertebrae, lies to the right of the Abdominal Aorta, ascends toward the Diaphragm, and passes through the caval opening into the posterior Mediastinum. It then penetrates the pericardial cavity and empties into the right atrium. Along its course, parietal and visceral vessels drain into the inferior vena cava.

The parietal venous tributaries include the lumbar veins (three to four on each side), which collect blood from the venous plexuses of the spine, Muscles, and Skin of the back, anastomosing via the ascending lumbar vein; and the inferior phrenic veins (right and left), which drain blood from the Inferior surface of the diaphragm and empty into the inferior vena cava.

The group of visceral tributaries comprises the testicular (or ovarian) veins, which drain the Testes (or Ovaries); the renal veins from the Kidneys; the suprarenal veins from the Adrenal Glands; and the hepatic veins, which carry blood from the Liver.

Venous blood from the lower extremities, pelvic walls, and pelvic organs is collected into two major venous vessels: the internal iliac and external iliac veins. These unite at the level of the sacroiliac joint to form the common iliac vein. Both common iliac veins subsequently merge to form the inferior vena cava.

The internal iliac vein is formed by veins that drain the pelvic organs, classified as parietal and visceral tributaries.

The parietal tributaries include the superior and inferior gluteal veins, obturator veins, lateral sacral veins, and iliolumbar veins. They collect blood from the pelvic, thigh, and Abdominal muscles. All these veins possess Valves. The visceral tributaries include the internal pudendal vein, which drains the Perineum and external genitalia; the vesical veins, carrying blood from the Urinary Bladder, vas deferens, Seminal Vesicles, and prostate (in males) or Vagina (in females); and the inferior and middle rectal veins, which collect blood from the walls of the rectum. Interconnecting with one another, the visceral tributaries form venous plexuses around the lesser pelvis organs (such as the urinary bladder, Prostate Gland, and rectum).

The VEINS OF THE lower extremity are divided into superficial and deep sets, which interconnect via anastomoses.

In the FOOT region, the subcutaneous veins form the plantar and dorsal venous networks of the foot, into which the digital veins empty. These venous networks give rise to the dorsal metatarsal veins, which serve as the origins of the great and small saphenous veins of the leg.

The great saphenous vein of the leg is a continuation of the medial dorsal metatarsal vein; along its course, it receives numerous superficial veins from the skin and empties into the femoral vein.

The small saphenous vein of the leg originates from the lateral part of the subcutaneous venous network on the dorsum of the foot, drains into the popliteal vein, and collects blood from the subcutaneous veins of the plantar and dorsal surfaces of the foot.

The deep veins of the lower extremity originate from the digital veins, which merge to form the plantar and dorsal metatarsal veins. The latter empty into the plantar and dorsal venous arches of the foot. From the plantar venous arch, blood flows via the plantar metatarsal veins into the posterior tibial veins. From the dorsal venous arch, blood enters the anterior tibial veins, which ascend while collecting blood from the surrounding muscles and bones, and subsequently unite to form the popliteal vein.

The popliteal vein receives small genicular veins and the small saphenous vein before continuing as the femoral vein.

Ascending superiorly, the femoral vein passes beneath the inguinal ligament to become the external iliac vein.

The femoral vein receives the deep vein of the thigh, the veins circumflexing the Femur, the superficial epigastric veins, the external pudendal veins, and the great saphenous vein of the leg. These vessels collect blood from the MUSCLES AND FASCIAE of the thigh and Pelvic Girdle, the hip joint, the lower part of the abdominal wall, and the external genitalia.