Question

Why do the fingers and hands have a large number of motor units? What capability does it give our digits?

What can be said about control of the neck? Does it have more motor units or less? What does that mean for fine motor control there?

Answer 1

Thw combination of individual motor neuron and all muscle fibresbthat innervates it is called motor unit.The number of fibres innervated by a motor unit is called innervarion ratio.

If a muscle is required is required for finer or delicate control its innervation ratio tends to be low,that is each motor neuron will innervate a small number of muscle fibres enabling nuances of movement of entire muscle.

This is the case for fingers and hands and why they have large number of motor units

Coming to muscles of neck,they need onky coarse movements,its motor units tends to have higher innervation ratio as no need of highly ccordinated movement,differential contraction to produce fine movement.