Patient Positioning
Patient seated facing the examiner with extended arm, palm up. The arm is resting comfortably on the examination table. Placing a pillow under the elbow leads to full extension of the joint.
Probe Positioning
Place the transducer on a lateral transverse plane over the brachioradial and brachial muscle to detect the radial nerve, then follow the superficial branch distally.
The radial nerve emerges from the radial groove on the lateral aspect of the humerus. At the level proximal to the elbow, the radial nerve is easily located between the brachioradial and brachial muscle. It passes anteriorly to the lateral epicondyle and continues in the forearm, where it branches into a superficial branch (primarily sensory) and a deep branch (primarily motor). The superficial branch nerve descends in the forearm under the brachioradialis. It crosses brachioradialis to enter posterior of forearm near the back of the wrist and supply dorsum of hand. The deep branch of the radial nerve pierces the supinator muscle, winds around the radius under the cover of supinator to reach posterior of the forearm.