Fig. 4.1
Median digit III orthodromic study recording over the median nerve at the wrist and stimulating digit III
Fig. 4.2
(a, b). Median palmar sensory study (orthodromic) recording over the median nerve at the wrist and stimulating at the mid-palm (a). This is located at the mid-point of a line drawn between the proximal wrist crease and the proximal interphalangeal (PIP) joint skin crease of digit III (b)
Fig. 4.3
Ulnar digit V orthodromic study recording over the ulnar nerve at the wrist and stimulating digit V with ring electrodes
Fig. 4.4
Superficial radial antidromic study. The distance between cathode and G1 is approximately the same as the distance from G1 to the tip of the thumb
Fig. 4.5
(a–c). Limb measurements (a) for antidromic recording of lateral (b) and medial (c) antebrachial cutaneous nerves of the forearm
Fig. 4.6
Sural sensory antidromic study stimulating behind the calf, the same distance above the inferior heel as the 5th metatarsophalangeal (MTP) joint is anterior to it; recording is postero-lateral to the lateral malleolus
Fig. 4.7
Superficial peroneal sensory study stimulating over the lateral leg and recording at the ankle
Fig. 4.8
Medial plantar orthodromic study stimulating at the medial arch (anode just proximal to the 1st MTP head) and recording behind the medial malleolus
Fig. 4.9
Lateral plantar orthodromic sensory study stimulating over the lateral sole (between 4th and 5th metatarsal bones) and recording behind the medial malleolus
Table 4.1 Positioning of Electrodes for Upper Limb Sensory Nerve Conduction Studies
|
Stimulation site |
Recording site | |
|---|---|---|
|
Median nerve | ||
|
Antidromic |
Stimulator placed at the wrist
Cathode at wrist: between tendons of palmaris longus (PL) and flexor carpi radialis (FCR).
Anode is located more proximally |
G1 ring or surface electrode placed on digit IIa
G2 is 3 cm distal to G1 |
|
Orthodromic |
Ring or bar electrode(s) on digit IIa
Cathode located at crease of first MCP joint. Anode is distal (between PIP and DIP joint)
Digit I can be studied, but distance must curve around thenar eminence to reflect course of nerve |
G1 surface electrode placed at the wrist (crease between tendons of PL and FCR)
G2 is 3 cm proximal to G1 |
|
Palmar study
Orthodromic |
Stimulator placed on palm.
In adults, cathode is located at the mid-palm, 7 cm from recording electrodes in a line with the webspace of digits II and III. |
G1 is placed at the middle of the proximal wrist (as above)
G2 is 3 cm proximal to G1 |
|
Ulnar nerve | ||
|
Antidromic |
Stimulator placed at the wrist
Cathode at wrist: just lateral to flexi carpi ulnaris (FCU) tendon. Anode is located more proximally |
G1 ring or surface electrode placed on digit Vb
G2 is 3 cm distal to G1 |
|
Orthodromic |
Ring or bar electrode(s) on digit Vb
Cathode located at skin crease of digit V MCP joint. Anode is distal (between PIP-DIP joints) |
G1 over the medial wrist (just lateral to FCU tendon)
G2 is 3 cm proximal to G1 |
|
Palmar
Orthodromic |
Stimulator placed on palm.
In adults, cathode is located at the mid-palm, 7 cm from recording electrodes in a line with the webspace of digits IV and V. |
G1 over the medial wrist at the proximal wrist crease (just lateral to FCU tendon)
G2 is 3 cm proximal to G1 |
|
Radial nerve | ||
|
Antidromic |
Stimulator place on dorsolateral radius.
Cathode is 8-10 cm proximal to G1 in adult limb |
G1 over superficial radial nerve as it crosses extensor pollicis longus tendon (base of ‘anatomical snuffbox’).
G2 placed over dorsum of first MCP |
|
Orthodromic |
Stimulator placed at skin crease of Digit I MCP joint.
Anode is distal (at DIP joint skin crease) |
G1 over radial bone at same distance proximal to the anatomical snuffbox as the tip of thumb is distal to it.
G2 is 3 cm proximal to G1 |
|
Medial antebrachial cutaneous nerve | ||
|
Antidromic |
Stimulator placed over medial elbow at mid-point between medial epicondyle and biceps tendon. |
G1 surface electrode place in adults, 12 cm distal to cathode (along line between cathode and medial wrist).
G2 is 3 cm distal to G1 |
|
Lateral antebrachial cutaneous nerve | ||
|
Antidromic |
Stimulator place in antecubital fossa, just lateral to biceps tendon.
Note: low stimulation intensity < 15 mA is required. Cathode must be manipulated to reduce concomitant stimulation of the median nerve which causes a motor twitch |
G1 surface electrode place in adults, 12 cm distal to cathode (along line between cathode and radial styloid / lateral wrist)
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