Veins return blood to the heart under low pressure, with thin walls and one-way valves in the limbs. Many lie just under the skin, which makes them the usual route for IVs and blood samples.
Return to the heart
Blood from the head and arms drains into the superior vena cava, and blood from the abdomen and legs drains into the inferior vena cava. Both empty into the right atrium.
Arm veins
The cephalic vein runs up the thumb side of the forearm and the basilic vein up the little-finger side. The median cubital vein crosses the front of the elbow between them and is the usual site for blood draws.
Choosing an IV site
A straight forearm vein away from a joint is comfortable and less likely to kink or dislodge. Hand veins also work, and the large veins at the front of the elbow are common in emergencies.
Deep and central veins
The internal jugular, subclavian and femoral veins are large deep veins used for central lines, usually placed with ultrasound. The internal jugular also reflects right atrial pressure as the jugular venous pulse.
| Vein | Location | Common use |
|---|---|---|
| Median cubital | Front of the elbow | Blood draws, large IV in emergencies |
| Cephalic | Thumb side of the forearm and arm | Peripheral IV |
| Basilic | Little-finger side of the forearm | Peripheral IV, PICC line |
| Dorsal hand veins | Back of the hand | Peripheral IV |
| Internal jugular | Side of the neck, under the sternocleidomastoid | Central line, jugular venous pressure |
At the bedside
Before an IV, look and feel for a straight, springy vein and avoid joints, injured limbs and an arm with a dialysis fistula or past lymph node removal. Feel for a pulse nearby so you do not puncture an artery.
Related guides
Written by Making Synapses. Topic reference: OpenStax, Anatomy and Physiology 2e (no text adapted).