The Journal of Neuroscience, March 15, 2001, 21(6):2150-2158
Tension Distribution to the Five Digits of the Hand by
Neuromuscular Compartments in the Macaque Flexor Digitorum
Profundus
Marc H.
Schieber,
Jennifer
Gardinier, and
Jie
Liu
Departments of Neurology and of Neurobiology and Anatomy,
University of Rochester School of Medicine and Dentistry, Rochester,
New York 14642
The macaque flexor digitorum profundus (FDP) consists of a muscle
belly with four neuromuscular regions and a complex insertion tendon
that divides to serve all five digits of the hand. To determine the
extent to which compartments within FDP act on single versus multiple
digits, we stimulated the primary nerve branch innervating each
neuromuscular region while recording the tension in all five distal
insertion tendons. Stimulation of each primary nerve branch activated a
distinct region of the muscle belly, so that each primary nerve branch
and the muscle region innervated can be considered a neuromuscular
compartment. Although each neuromuscular compartment provided a
distinct distribution of tension across the five distal tendons, none
acted on only one digital tendon. Most of the distribution of tension
to multiple digits could be attributed to passive biomechanical interactions in the complex insertion tendon, although for the larger
compartments a wider distribution resulted from the broad insertion of
the muscle belly. Nerve ligations excluded contributions of spinal
reflexes or distal axon reflexes to the distribution of tension to
multiple digits. We conclude that the macaque FDP consists of four
neuromuscular compartments, each of which provides a distinct
distribution of tension to multiple digits.
Key words:
compartment; digits; distribution; fingers; force; hand; macaque; multitendoned; muscle; neuromuscular; tension; thumb
Copyright © 2001 Society for Neuroscience 0270-6474/01/2162150-09$05.00/0
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