The extensor
carpi radialis longus, extensor carpi radialis brevis and extensor carpi
ulnaris are relatively long and slender muscles situated on the back of
the forearm. The extensor carpi radialis longus muscle is just to the
rear of the brachioradialis, with the extensor carpi radialis brevis
underneath the longus.
Both are on
the thumb side of the forearm. The extensor carpi ulnaris is situated
more toward the little finger side of the forearm. Most of these muscles
mass is situated close to the elbow, while their long tendons cross the
wrist and attach to the bones on the back of the hand.