Fig. 2
From: A database of upper limb surface electromyogram signals from demographically diverse individuals

Sensors are named with a prefix S followed by the sensor number. 4 sensors are placed equally spaced around the wrist joint (S1, S3, S4 are shown. S2 is on the underside, below S1). Sensors S5 to S12 are placed equally spaced around the belly of the forearm. Sensors S5 and S6 are shown. The rest of the sensors are equally spaced around the forearm in the clockwise direction so that S12 is adjacent to S5 as shown.