Central course of digital axons within the median nerve of Macaca mulatta

Research output: Contribution to journalArticle

Abstract

The traditional view that axons are not functionally grouped within proximal human nerve is based on the interfascicular dissections of Sunderland ('45). However, microstimulation and microneurography (Schady et al., '83a; Hallin, '90) reveal proximal grouping of cutaneous sensory axons from small areas of skin. In the present studies, conjugates of horseradish peroxidase with wheat germ agglutinin (HRP-WGA) were used to trace the course of digital nerve axons within the median nerve of Macaca mulatta. The electrophysiologic findings were confirmed, suggesting the potential for precise surgical realignment of functionally related axons even after proximal nerve transection. Radial digital nerves were labeled in the thumb (bilateral, 1 animal), the index finger (unilateral, 2 animals), and the middle finger (bilateral, 1 animal). Median nerve cross sections were cut at 1-cm intervals, treated with tetramethyl benzidine to demonstrate HRP-WGA within axons, and compiled to form maps of each digital nerve 'territory' within the median nerve. These territories were limited to a single, densely labeled fascicle at the wrist level. They expanded somewhat in the forearm to encompass clusters of labeled axons within a matrix of unlabeled axon profiles. The clusters were more loosely packed in the arm, occupying 1/3 to 1/6 of the nerve cross section at the entrance to the brachial plexus. The three digital nerve territories studied were widely separated at the wrist level. In the proximal arm, there was moderate intermingling of axons from adjacent digits, but those to the middle finger and thumb remained segregated. Territory configuration differed widely overall, but was moderately constant for each digit. The location of territories within the nerve was often strikingly similar from right to left and from animal to animal, with occasional prominent variations reflecting isolated rotation of one nerve.

Original languageEnglish (US)
Pages (from-to)197-209
Number of pages13
JournalJournal of Comparative Neurology
Volume311
Issue number2
StatePublished - 1991

Fingerprint

Median Nerve
Macaca mulatta
Axons
Fingers
Thumb
Wrist
Arm
Wheat Germ Agglutinin-Horseradish Peroxidase Conjugate
Radial Nerve
Skin
Wheat Germ Agglutinins
Brachial Plexus
Horseradish Peroxidase
Forearm
Dissection

Keywords

  • axon tracing
  • HRP-WGA
  • peripheral nerve
  • sensory system
  • somatotopy

ASJC Scopus subject areas

  • Neuroscience(all)

Cite this

Central course of digital axons within the median nerve of Macaca mulatta. / Brushart, Thomas.

In: Journal of Comparative Neurology, Vol. 311, No. 2, 1991, p. 197-209.

Research output: Contribution to journalArticle

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