Thread by @theneurolander

Autonomous Sensory Zones
(peripheral nerves)

Median nerve illustration by Guttmann (1939)

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Definition

“regions where single nerve roots supply distinct and non-overlapping areas of skin”

- small portion of dermatome
- few nerve roots have such autonomous zones
- great variability

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Sensory zones

a.maximal zone: maximal area supplied by a peripheral nerve
- maximal=intermediate+autonomous

b.intermediate zone: area of overlap of the maximal zone of different peripheral nerves

c.autonomous zone: area exclusively supplied by a particular peripheral nerve
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Autonomous zones of various nerves:

A. Radial nerve
B. Median nerve
C. Ulnar nerve
D. Common peroneal nerve
E. Sciatic nerve

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Radial nerve

area: 1st dorsal web space of hand (Anatomical snuff box)

“according to some authors, radial nerve and common peroneal do not have autonomous zones although complete transection of the nerve results in sensory loss over the mentioned regions”

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Median nerve

area: distal phalanx (tip) of index finger (2nd finger)
- tip of thumb (other possible area)

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Ulnar nerve

area: distal phalanx (tip) of little finger (5th finger)

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Common peroneal nerve

area: central strip on dorsum of foot

“according to some authors, radial nerve & common peroneal do not have autonomous zones although complete transection of the nerve results in sensory loss over the mentioned regions”

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Sciatic nerve

area: mixed pattern of common peroneal nerve and posterior tibial nerve

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Deep peroneal nerve

area: 1st dorsal web space

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Posterior tibial nerve

area: sole of foot

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Why is important to know the autonomous sensory zones?

“anesthesia in an autonomous zone indicates a complete lesion of that particular nerve”

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MRC grading of sensory recovery tested on autonomous zone

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