Low-frequency filter was 8 Hz, high-frequency filter was 3.2 kHz, duration of pulse was 0.1 ms, and rate of pulse was 1/s. Sensitivity, sweep speed, and the machine used were not specified.

This study was performed in the supine position.

Following the orthodromic method [1], the median and ulnar sensory nerve conduction studies were performed. Finger to wrist sensory nerve conduction study (Fig. 1) and palm to wrist sensory conduction study (Fig. 2) were done orthodromically at the wrist. The active electrode (A) was placed proximal to the distal crease at the wrist; the reference (R) was placed proximally. The authors used a standard plastic bar electrode (interelectrode distance was 3 cm) placed over the nerve at the wrist with the orientation of the two recording electrodes along the line of the nerve. For the median nerve (R1), electrodes were placed between the tendons of the flexor carpi radialis and the palmaris longus muscles (ideally proximal to the distal wrist crease). For the ulnar nerve (R2), electrodes were placed just lateral to the tendon of the flexor carpi ulnaris (ideally proximal to the distal wrist crease). The electrodes for the median and ulnar recordings at the wrist were placed at an identical distance from the stimulating sites for the median and ulnar nerves at the fingers (digit II, digit III, and digit V) and in the palm (fixed distance was not specified). Ground (G) electrode position was not specified in the report; the figure shows the ground electrode placed on the palm. Median (R1) and ulnar (R2) nerve recordings were made separately.

The finger to wrist sensory nerve conduction studies were done orthodromically with stimulation by the ring electrodes on a single digit with the cathode electrode (−) around the proximal phalanx and the anode electrode (+) 2–3 cm distally around the same digit. The median nerve was stimulated to digit II (S1) and digit III (S2); the ulnar nerve was stimulated to digit V (S3). The palm to wrist sensory conduction studies were done orthodromically with the stimulator placed, cathode (−) proximally, in midpalm over the digital nerves in the intermetacarpal spaces (2–3 for the median nerve, 3–4 for the ulnar nerve). The fixed distance was not specified. Nerves were stimulated by 0.1 ms duration supramaximal stimuli at a rate of 1/s.

Onset latency (ms) was measured from the onset of the stimulus to the onset of the negative deflection of the evoked sensory nerve action potential (SNAP). The average finger-to-wrist distance (cm) was 13.2 ± 1.1 (from digit II and digit III) and 11.2 ± 1.22 (from digit V). The median and ulnar palm-to-wrist distances (cm) both averaged 7.5 ± 0.79 and were generally chosen as to be identical. Onset latency was converted in sensory nerve conduction velocity (SNCV) by dividing the latency into the distance. All examinations were performed in thermostatically controlled rooms, and extremities that appeared to be cool were soaked in warm water until felt to be of normal temperature. A comparison between fingers of the same hand was made for finger to wrist and palm to wrist nerve conduction velocities. The author performed 268 median and ulnar sensory nerve conductions (Table 1) in 268 subjects (184 women and 82 men; in 2 cases, sex was not recorded; age range 13–90 years; average age 43.7 years).