G1 active recording electrode
G1: fifth digit
Record from digit V with G1.
Table 2 · p.373 ↗
Sensory study
Upper limb
Ulnar sensory nerve conduction study
Place G1 on the fifth digit and stimulate at the wrist just radial to the flexor carpi ulnaris tendon.
01 · Placement
G1, G2, stimulation and ground landmarks
G2 reference electrode
G2: 4 cm distal to G1
Place G2 4 cm distal to G1.
Table 2 · p.373 ↗Stimulation site
Wrist stimulation: just radial to the FCU tendon
Stimulate at the wrist just radial to the flexor carpi ulnaris tendon, 14 cm from G1.
Table 2 · p.373 ↗Ground region
Ground electrode region
AANEM places the ground between the stimulating and recording electrodes. The model shows a usable ulnar wrist region, not a single mandatory point.
Table 2 · p.373 ↗02 · Reference values
Adult normal limits
| Measure | Reference limit | Basis |
|---|---|---|
| SNAP onset-to-peak | ≥10 µV | 3rd percentile lower limit |
| SNAP peak-to-peak | ≥9 µV | 3rd percentile lower limit |
| Onset latency | ≤3.1 ms | 97th percentile upper limit |
| Peak latency | ≤4.0 ms | 97th percentile upper limit |
| Conduction velocity | ≥45 m/s | Published 3rd percentile |
03 · Technique
Acquisition conditions
Fixed distance
G1 to wrist stimulation: 14 cm
Sensitivity
20 µV/div
Filter
20 Hz–2 kHz
Sweep
1 ms/div
Temperature
Maintain dorsal hand skin temperature >32°C
Ground
Place the ground between the stimulating and recording electrodes
Primary evidence
Method-matched AANEM reference data
Adult antidromic ulnar sensory reference values for digit V; amplitude is also affected by age and BMI.