Sensory Studies



Fig. 4.1
Median digit III orthodromic study recording over the median nerve at the wrist and stimulating digit III



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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)


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Fig. 4.3
Ulnar digit V orthodromic study recording over the ulnar nerve at the wrist and stimulating digit V with ring electrodes


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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


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Fig. 4.5
(ac). Limb measurements (a) for antidromic recording of lateral (b) and medial (c) antebrachial cutaneous nerves of the forearm


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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


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Fig. 4.7
Superficial peroneal sensory study stimulating over the lateral leg and recording at the ankle


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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


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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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Nov 18, 2017 | Posted by in PEDIATRICS | Comments Off on Sensory Studies

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