The iliac veins are inaccessible on the surface of the body and are located deeper, between the abdominal and pelvic cavities. The iliac vein is also known as the common iliac vein. The external iliac vein and the internal iliac vein join anteriorly at the sacroiliac joint to form the common iliac vein, which is divided into two branches, the left and the right. The left common iliac vein is slightly longer and runs medial to the common iliac artery; the right common iliac vein is slightly shorter and runs deeper to the common iliac artery. The right and left common iliac veins are the largest branches of the inferior vena cava. If the common iliac vein is compressed, such as tumor compression or thrombosis, it is easy to lead to the lower limbs can not return to the normal flow of blood, resulting in blood circulation obstacles in the lower limbs, resulting in varicose veins of the lower limbs, lower limb swelling, lower limb ulcers and other conditions. Clinical examination of hip veins includes ultrasound, CTA, MRA and other examination methods. If discomfort occurs in the lower limbs, you should go to the hospital for examination and treatment in time to prevent other damages caused by delayed condition.