Get Elbow Anatomy Radial Nerve Pictures. In the arm, it courses posterior to the humerus in the spiral groove and pierces the intermuscular septum in the distal aspect of the arm to lie anterior to the lateral condyle. This may occur at several locations in the elbow and upper forearm.
Posterior cutaneous nerve of the arm. The radial nerve begins from the inside of the upper arm, travels diagonally across to the outer elbow and then again crosses to the thumb side of the forearm and into the back of the thumb, index and half of the middle finger. Anatomically, the radial nerve emerges from the supinator and then becomes the pin (posterior interosseous nerve).
These nerves carry signals from the brain to the muscles that move the arm.
The pin allows for extension of the wrist and fingers (straightening out). The radial nerve then curves anteriorly around the lateral epicondyle at the elbow, where it divides into a superficial and a deep branches (posterior interosseous nerve) under the margin of the brachioradialis muscle in the lateral border of the cubital fossa. A patient's guide to elbow anatomy. If the bifurcation had not yet occurred at the point of measurement, the diameter of the radial nerve was recorded.