Figure 2. US section at the junction of the upper and middle thirds of the anterior side of the forearm with (panel B) and without delineation of muscles (panel A).

The FCRM is located in the middle of the superficial part of the anterior compartment of the forearm. The EMG needle (white arrowheads) is entirely viewed and inserted in the FCRM. This muscle has a characteristic central septum (yellow arrowheads). 

BR: Brachioradialis muscle; FDS: Flexor digitorum superficialis muscle; FDP: Flexor digitorum profundus muscle; FPL: Flexor pollicis longus muscle; PT: Pronator teres muscle; N: Median nerve; A: Radial artery; R: Radius; FCRM: Flexor carpi radialis muscle; EMG: Electromyography.

Note: These ultrasound images were taken from a voluntary medical resident who consented to the procedure.