The human foot and the human handHumphry, George Murray, Sir
Science
The human foot and the human hand
Humphry, George Murray, Sir
Foot; Hand
I come now to speak more particularly of the movements that take
place in the Hand. I have already said that the mobility of the thumb
is the chief characteristic of the hand as distinguished from the
foot. Another important distinction between the hand and the foot is
the greater length and mobility of the fingers as compared with the
toes. The toes are short; and our power of moving them is, under any
circumstances, slight. They constitute a small, and, comparatively,
unimportant, part of the foot. The fingers, on the contrary, are long;
they form a half, and, including the thumb, the more important half,
of the hand. Without them the rest of the hand, indeed the rest of the
limb, would be comparatively useless. Their movements are varied and
free, and take place with singular facility and rapidity. We can bend
them quite down upon the palm, and can extend them beyond the straight
line; we can separate them from one another to a considerable extent;
and we can bring them together with some force, as a waiter does when
he carries a number of wine-glasses between his fingers; and persons
who have lost the thumb contrive to hold a pen, a knife or fork, or
other things, between the fingers.
[Illustration: Fig. 65.
Muscles of forearm and hand.]
Let me endeavour to give you an idea of some of the muscles which are
concerned in executing these movements.
The wrist and hand are bent forwards upon the forearm by means of
three muscles (A, B, C, fig. 65). These all pass downwards from
the inner side of the lower end of the armbone. The outer and inner
ones (A and C) are connected, by tendons, with the wrist-bones; and the
tendon of the middle one (B) runs over the wrist and becomes spread
out in the palm like a fan, so as to support the skin of the palm and
to protect the nerves and blood-vessels, which lie beneath it, from
injurious pressure, when we grasp any substance firmly in the hand. The
fan-like expansion of this tendon in the palm is called the “palmar
fascia.” It is very strong, and is connected, below, with the ends of
the metacarpal bones, and with the sheaths of the fingers. The bundle
of muscles near D forms what is called the “ball of the thumb,” and
serves to move the thumb in various directions.
[Illustration: Fig. 66.
Muscles and tendons of hand.]
Beneath these three muscles which bend the wrist and strengthen the
palm lies another set of muscles (A, B, fig. 66) which bend the
thumb and fingers. They pass from the bones of the forearm, and end in
long tendons or “leaders” which run over the wrist and palm and along
the fingers and are firmly connected with the last phalanges of the
fingers. They lie close to the bones in their whole course, and are
held in their places by sinewy cross bands and sheaths which are seen,
both at the wrist and in the fingers, in fig. 65.
[Illustration: Fig. 67.
Muscles and tendons on back of forearm and hand.]
Public-domain text, read in full here on John Shaqi.
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