Friday, March 1, 2013

The Cephalic Vein: You're Sooo Superficial

I haven't written much about veins on this blog, and I don't know why. Veins are awesome. Veins are your friends. Their pals arteries aren't too shabby either. And in figure drawing, it's not a bad thing to know how to draw them in the right places. While some vein placement is quite variable from person to person, there are certain veins that we can always count on to peek out at us in the same places. These include the external jugular vein on the neck (which I briefly mentioned in The Anterior Neck: Theme and Variations,) the great saphenous vein on the inner leg, and the basilic, median cubital, and cephalic veins on the arm.

Veins are different from arteries in that they typically carry deoxygenated blood (as opposed to oxygenated blood, which is typically carried by arteries.) There is an exception to this in the case of the pulmonary arteries and veins, which I'd love to explain now but would rather save for a future, general blood vessel post. Who can resist a good general blood vessel post?

For now I just want to show you a nice example I found of a prominent cephalic vein showing on the radial side of the wrist. This is one of two places we may typically see the cephalic vein. (The other is on the upper arm, running over the lateral side of the biceps brachii muscle, just before the vein enters the deltoid furrow, the crease between the deltoid and pectoralis major muscles. I will save that view for another compelling blood vessel post.)

Let's just take a look at this view today:



The cephalic vein, because its superficial location over the radial side of the wrist and its easy access, is often used as a site for I.V. placement. Its course may be fairly straight, or more jagged like the one seen here. It will continue upward on the ventral side of the forearm, run over the lateral side of the biceps brachii muscle, and enter the deltoid furrow, where is often disappears from surface view. If it doesn't disappear there, it will disappear when it runs deep to the clavicle and merges with the subclavian vein.

As a bonus, there are four tendons clearly visible here as well. Let's take a look.


On the radial side of the wrist, just at the base of the thumb, we can see the tendons of extensor pollucis longus and extensor pollucis brevis muscles. The muscles, as their names tell us, extend the thumb, and one is longer than the other. (Just slightly so: The tendon of extensor pollucus longus extends all the way to the first distal phalanx of the thumb, and the tendon of extensor pollucus brevis extends only to the first proximal phalanx, so both can be extended independently of one another. You can read more about these thumb tendons in The Dorsal Hand: The Dorsal Foot's Better Looking Sibling.

On the ventral side of the wrist, we can see the tendons of two ventral compartment muscles, palmaris longus and flexor carpi radialis. Don't be alarmed if you can't find your own palmaris longus tendon; it's missing in 12 to 15 percent of the human population. You can read more about these tendons in The Ventral Forearm: What are those Tendons? 

That's it for now. Thanks for stopping by. More to come soon. Perhaps anterior torso? More superficial veins? Ooh, how about more terminology? It's so hard to decide. We'll see.

2 comments:

  1. I am a reborn doll artist and find your blog to be a tremendous help in achieving realism. I struggle quite frequently with vein placement on my dolls so thank you very much!

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    1. I am very happy to hear this. Thank you!

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