Moving toes
Fingers and toes are morphologically different. The function of an
animal is different from human, as human assumes an erect posture.
Animals run with four legs, in a coordinated way. But a human, even
if he assumes four leg posture cannot run, as he does with two legs.
Animals drink water by ending its neck into the surface, and to make
it easy when the forelimbs bend to lower the head, the hind limbs extend
or rise to make it easier.
This is called Tonic Assymatric reflex, by neck contraction. This
phenomenon may be seen in a newborn.
The new born cannot extend the hand, i.e. it cannot open the fingers
by itself, voluntarily.
The movement of thumb is across the palm, till the myelination
process becomes complete. As the child learns to stand, the morphology
changes entirely. Hence the movements are organised according to the
need of the human requirements.
Moreover, once the organisation of the movement is postulated by the
brain according to the evolutionary changes or functional changes, the
muscles get reorganised to the need.
For example, the different planes of origin of the muscles in the
forearm and leg control the movement of the hand and toes.
The area of their origin and insertion decides the need of movement
and nature of movement.
For example, there are two groups of muscles in the forearm,
attaching itself to the different portion of finger bones at different
sites to perform finer movement, as we play a guitar or veena.
Such finer and planned insertion is not available in the toes. Hence
individual movement cannot be performed as in fingers.
Dr. V. NAGARAJAN
Courtesy: The Hindu
|