G1 active recording electrode
G1: medial forearm
Place G1 on the medial forearm, 10 cm distal to S1 on a straight line from the medial antecubital fossa toward the ulnar aspect of the wrist.
Table 2 · p.373 ↗
Sensory study
Upper limb
Medial antebrachial cutaneous sensory nerve conduction study
Record from the medial forearm and stimulate at the elbow between the medial epicondyle and distal biceps tendon.
01 · Placement
G1, G2, stimulation and ground landmarks
G2 reference electrode
G2: 3 cm distal bar electrode
Place G2 3 cm distal to G1 along the same medial-forearm line toward the ulnar wrist.
Distance · 3 cm distal to G1
Table 2 · p.373 ↗Stimulation site
Stimulation: between medial epicondyle and biceps tendon
Stimulate in the medial antecubital fossa midway between the medial epicondyle and the distal biceps tendon.
Distance · 10 cm from G1
Table 2 · p.373 ↗Ground region
Ground electrode region
Place the ground on the medial forearm between the antecubital stimulation site and G1.
Table 2 · p.373 ↗02 · Reference values
Adult normal limits
| Measure | Reference limit | Basis |
|---|---|---|
| SNAP onset-to-peak | ≥4 µV | 3rd percentile lower limit |
| SNAP peak-to-peak | ≥3 µV | 3rd percentile lower limit |
| Onset latency | ≤2.6 ms | 97th percentile upper limit |
03 · Technique
Acquisition conditions
Fixed distance
G1 to stimulation site: 10 cm
Sensitivity
10 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 medial antebrachial cutaneous sensory reference values.