Sensory study One side shown; mirror the placement for the opposite limb

Superficial radial sensory

Superficial radial sensory nerve conduction study

Record over the extensor pollicis longus tendon near the anatomical snuffbox and stimulate proximally along the radius.

Placement and evidence

Select a row to focus its 3D marker

Place G1 in the anatomical snuffbox on the dorsolateral wrist, directly over the superficial radial nerve as it crosses the thumb extensor tendons. Table 2 · p.373

Place G2 on the dorsal thumb 3–4 cm distal to G1, continuing along the same line over the thumb extensor tendons. Distance · 3–4 cm distal to G1 Superficial radial sensory technique · p.19

Stimulate over the distal mid-radius, 10 cm proximal to G1 along the radial border of the forearm; orient the cathode toward G1. Distance · 10 cm proximal to G1 Table 2 · p.373

Place the ground on the dorsal radial wrist or distal forearm between S1 and G1, clear of the recording electrodes. Table 2 · p.373

Normal waveform schematic

Educational SNAP schematic. The dashed line marks this protocol's latency reference limit; this is not a patient waveform.

Adult reference values

Use only when the test method matches

SNAP onset-to-peak≥7 µV3rd percentile lower limit

SNAP peak-to-peak≥11 µV3rd percentile lower limit

Onset latency≤2.2 ms97th percentile upper limit

Peak latency≤2.8 ms97th percentile upper limit

Conduction velocity≥50 m/sPublished 3rd percentile

Technical conditions

Fixed distanceG1 to stimulation site: 10 cm

Sensitivity5–10 µV/div

Filter20 Hz–2 kHz

Sweep1 ms/div

TemperatureMaintain dorsal hand skin temperature >32°C

GroundBetween the stimulating and recording electrodes

Primary evidence

Every marker is tied to a published table

The 3D coordinates project AANEM's written anatomical landmarks onto an educational model. Clinical testing still requires palpation of the patient's anatomy, measured distances and laboratory-validated reference values.

Open the original AANEM table Table 3 · p.374 · Muscle & Nerve, 2016

3D placement model