Sensory study Lower limb

Saphenous sensory nerve conduction study

Record between the tibialis anterior tendon and medial malleolus and stimulate 14 cm proximally in the medial calf groove.

01 · Placement

G1, G2, stimulation and ground landmarks

G1 active recording electrode

Place G1 at the medial-anterior ankle halfway between the tibialis anterior tendon and the medial malleolus.

G2 reference electrode

Place G2 3–4 cm distal to G1 toward the medial border of the foot, aligned with the distal saphenous nerve.

Distance · 3–4 cm distal to G1

Stimulation site

Stimulate 14 cm proximal to G1 in the medial calf groove between the tibia and the medial gastrocnemius.

Distance · 14 cm from G1

Ground region

Place the ground on the medial lower leg between the medial-calf stimulation site and ankle recording electrodes.

02 · Reference values

Measure	Reference limit	Basis
SNAP amplitude	≥4 µV	AANEM educational reference
Conduction velocity	≥40 m/s	14 cm antidromic technique
Distal peak latency	≤4.4 ms	14 cm antidromic technique

03 · Technique

Fixed distance G1 to stimulation site: 14 cm

Sensitivity 5–10 µV/div

Filter 20 Hz–2 kHz

Sweep 1 ms/div

Temperature Maintain dorsal foot skin temperature >31°C

Ground Place the ground between the stimulating and recording electrodes

Primary evidence

Saphenous sensory reference values for a 14 cm medial-ankle recording technique.