human anatomy Human anatomy (gr. ἀνατομία, "dissection", from ἀνά, "up", and τέμνειν, "cut") is primarily the scientific study of the morphology of the human body. Anatomy is subdivided into gross anatomy and microscopic anatomy. Gross ...

, the common iliac veins are formed by the

external iliac vein The external iliac veins are large veins that connect the femoral veins to the common iliac veins. Their origin is at the inferior margin of the inguinal ligaments and they terminate when they join the internal iliac veins (to form the common i ...

s and

internal iliac vein The internal iliac vein (hypogastric vein) begins near the upper part of the greater sciatic foramen, passes upward behind and slightly medial to the internal iliac artery and, at the brim of the pelvis, joins with the external iliac vein to for ...

s. The left and right common iliac veins come together in the

abdomen The abdomen (colloquially called the gut, belly, tummy, midriff, tucky, or stomach) is the front part of the torso between the thorax (chest) and pelvis in humans and in other vertebrates. The area occupied by the abdomen is called the abdominal ...

at the level of the fifth lumbar vertebra, forming the

inferior vena cava The inferior vena cava is a large vein that carries the deoxygenated blood from the lower and middle body into the right atrium of the heart. It is formed by the joining of the right and the left common iliac veins, usually at the level of the ...

. They drain

blood Blood is a body fluid in the circulatory system of humans and other vertebrates that delivers necessary substances such as nutrients and oxygen to the cells, and transports metabolic waste products away from those same cells. Blood is com ...

from the

pelvis The pelvis (: pelves or pelvises) is the lower part of an Anatomy, anatomical Trunk (anatomy), trunk, between the human abdomen, abdomen and the thighs (sometimes also called pelvic region), together with its embedded skeleton (sometimes also c ...

and lower limbs. Both common iliac veins are accompanied along their course by common iliac arteries.

Structure

The

and

unite in front of the sacroiliac joint to form the common iliac veins. Both common iliac veins ascend to form the inferior vena cava behind the right common iliac artery at the level of the fifth lumbar vertebra. The vena cava is to the right of the midline and therefore the left common iliac vein is longer than the right. The left common iliac vein occasionally travels upwards to the left of the

aorta The aorta ( ; : aortas or aortae) is the main and largest artery in the human body, originating from the Ventricle (heart), left ventricle of the heart, branching upwards immediately after, and extending down to the abdomen, where it splits at ...

to the level of the

kidney In humans, the kidneys are two reddish-brown bean-shaped blood-filtering organ (anatomy), organs that are a multilobar, multipapillary form of mammalian kidneys, usually without signs of external lobulation. They are located on the left and rig ...

, where it receives the left

renal vein The renal veins in the renal circulation, are large-calibre veins that drain blood filtered by the kidneys into the inferior vena cava. There is one renal vein draining each kidney. Each renal vein is formed by the convergence of the interlobar v ...

and crosses in front of the aorta to join the inferior vena cava. The right common iliac vein is virtually vertical and lies behind and then lateral to its artery. Each common iliac vein receives iliolumbar veins, while the left also receives the median sacral vein which lies on the right of the corresponding artery.

Clinical significance

Overlying arterial structures may cause compression of the upper part of the left common iliac vein. Compression of the left common iliac vein against the fifth lumbar vertebral body by the right common iliac artery as the artery crosses in front of it traditionally happens in

May–Thurner syndrome May–Thurner syndrome (MTS), also known as the iliac vein compression syndrome, is a condition in which compression of the common venous outflow tract of the left lower extremity may cause discomfort, swelling, pain or iliofemoral deep vein thro ...

. Continuous pulsation of the common iliac artery may trigger an

inflammatory response Inflammation (from ) is part of the biological response of body tissues to harmful stimuli, such as pathogens, damaged cells, or irritants. The five cardinal signs are heat, pain, redness, swelling, and loss of function (Latin ''calor'', '' ...

within the common iliac vein. The resulting intraluminal

elastin Elastin is a protein encoded by the ''ELN'' gene in humans and several other animals. Elastin is a key component in the extracellular matrix of gnathostomes (jawed vertebrates). It is highly Elasticity (physics), elastic and present in connective ...

and

collagen Collagen () is the main structural protein in the extracellular matrix of the connective tissues of many animals. It is the most abundant protein in mammals, making up 25% to 35% of protein content. Amino acids are bound together to form a trip ...

deposition can cause intimal

fibrosis Fibrosis, also known as fibrotic scarring, is the development of fibrous connective tissue in response to an injury. Fibrosis can be a normal connective tissue deposition or excessive tissue deposition caused by a disease. Repeated injuries, ch ...

and the formation of venous spurs and webs. This can lead to narrowing of the vein and cause persistent unilateral leg swelling, contributing to

venous thromboembolism Venous thrombosis is the blockage of a vein caused by a thrombus (blood clot). A common form of venous thrombosis is deep vein thrombosis (DVT), when a blood clot forms in the deep veins. If a thrombus breaks off ( embolizes) and flows to the lun ...

References

{{Authority control Veins of the torso Angiology Anatomy Veins