Air embolism and veins is greater than atmospheric pressure, an air embolus does not often happen when a blood vessel is injured. In the veins above the heart, such as in the head and neck, the venous pressure may be less than atmospheric and an injury may let air in. This is one reason why surgeons must be particularly careful when operating on the brain, and why the head of the bed is tilted down when inserting or removing a central venous catheter from the jugular or subclavian veins. When air enters the veins, it travels to the right side of the
Lumbar veins lumbar veins on the left pass behind the abdominal aorta to reach the inferior vena cava and "all" lie behind the sympathetic trunks. The iliolumbar veins join the common iliac veins. Lumbar veins The lumbar veins are veins running along the inside of the posterior abdominal wall. They are the lumbar equivalent of the posterior intercostal veins. They are four in number and accompany the four lumbar arteries, with the vein lying superior to the artery (the same arrangement as in the intercostal neurovascular bundles). The first and second lumbar veins usually join the ascending lumbar vein rather than the