|
the primate hand
Versatility is the hallmark of the primate hand.
With minor variations between species, thirty-five joints accommodate
the palm and fingers to branches and objects of all sizes, shapes, and
orientations.
Six layers of muscles produce movements that propel the
animals and effect gripping patterns used in maintaining feeding and resting
positions, securing an infant's hold on its mother, removing parasites from the
fur, catching insects, plucking fruits, extracting foods from their
source, and positioning objects for
tactile,
olfactory, and visual scrutiny.
Multiple structural constraints on mobility stabilize joints in regions
that are habitually exposed to stresses during these positional and
manipulatory activities.
The locations and configurations of these
constraints vary considerably among species, as do the relative proportions of
hand segments, reflecting the diversity of their locomotor and feeding
patterns.
The key to the
versatility of primate hands is to be found in the nature of the thumb and the
fingertips.
The thumb is structurally and functionally differentiated
from the rest of the fingers.
The tips of all five digits are
relatively broad, with moist, ridged, sensitive palmar pads that are supported
by nails.
The advantages of a
grasping hand are most apparent in the levels of the
forest where vines, bushes, and
the slender upper and outer branches of the canopy offer the least purchase to
a paw with claws on the fingertips.
Differentiation of the thumb
provides the ability for prehension of objects by
one hand.
The variety
and skill of prehensile activities depend upon the
details of joint structure, the
relative length of the thumb and fingers, the sensory nerve supply to the
distal digital pads, and the motor control of
hand movements by the
brain.
Pounding with
hand-held hammer stones has been the tool using and making activity with the
greatest frequency and antiquity in hominid evolution.
This activity
directs large, repetitive force to the central region of the palm.
Production of forceful accurate blows with a hand-held stone requires
control of the stone with a firm precision grip assuring both retention of the
stone in the hand while still allowing for fine adjustments in
orientation.
When a
mammal is motivated to learn, the brain responds
plastically.
Repetitious hand movements actually change brain
structure.
As brain maps grow individual
neurons get more efficient in two stages.
Initially
individual neurons within the
map grow and became more efficient.
Fewer neurons are required to perform the task as
the brain responds.
Stabilization of objects that are held in the
other hand and pounded by hammer stones in the production of tools also
requires a firm precision grip and the ability to vary the orientation of the
stone.
The central region of the modern human palm is stabilized,
buttressed, and protected against intrinsic and extrinsic forces associated
with the grasp and manipulation of stones in pounding by robust bones and a
fat-pad.
A secure grasp and controlled maneuvering of stones by the
thumb, fingers, and palm are facilitated by a unique pattern of hand
proportions and joint-and-muscle configurations that permit cupping of the hand
and the formation of a wide variety of grips.
The proportionately long
thumb and short fingers with broad fingertip pads are able to maneuver a stone
and to hold it firmly, exploiting the leverage of the fingers while bracing the
stone against the palm.
The unique arrangement of intrinsic musculature
and orientation of joints along the second, third, and fifth rays, favoring
rotation of the fingers, allow optimal positioning of thumb and fingers for
grasping and throwing stones.
Grips found through experimentation
to control stones most comfortably and effectively involved primarily the
thumb, index, and third fingers.
These included the pad-to-side and
three-jaw-chuck thumb/finger grips and extensions of these grips that
incorporate the palm as a passive buttress.
The three-jaw-chuck
thumb/finger grip is most effective both for wielding hammer stones and for
throwing stones.
Stones of ~ 500 grams, comparable to tennis balls, are
held by the thumb, index, and third fingers, frequently against the side of the
flexed fourth finger which in turn is buttressed by the flexed fifth finger as
a support.
The tip of the thumb and index and third fingertips control
the orientation of the stone and keep it away from the palm, so that the
leverage of these rays is exploited in propelling the stone.
The
pressure and leverage of these rays are important factors in controlling the
rotation and speed of an object thrown by the hand.
The modern human
hand structure of the joints along the fifth ray probably contributes to the
effectiveness of the finger/active-palm squeeze grip.
The
finger/active-palm squeeze grip employs all the fingers in convergence of the
palm around a cylindrical tool, such as an antler hammer, to secure it, so that
the tool functions
as an extension of the hand and/or arm.
The use of small modern
tools such as needles and pencils involves the rotation and
translation of objects by
the pads of the fingertips opposed to the tip of the thumb pad, exploiting
a unique human
compartmentalization. |
|
 |
This web site is not a commercial web site and
is presented for educational purposes only.
This website defines a
new perspective with which to engage reality to which its author adheres. The
author feels that the falsification of reality outside personal experience has
forged a populace unable to discern propaganda from reality and that this has
been done purposefully by an international corporate cartel through their
agents who wish to foist a corrupt version of reality on the human race.
Religious intolerance occurs when any group refuses to tolerate religious
practices, religious beliefs or persons due to their religious ideology. This
web site marks the founding of a system of philosophy named The Truth of the
Way of the Lumière Infinie - a rational gnostic mystery religion based
on reason which requires no leap of faith, accepts no tithes, has no supreme
leader, no church buildings and in which each and every individual is
encouraged to develop a personal relation with the Creator and Sustainer
through the pursuit of the knowledge of reality in the hope of curing the
spiritual corruption that has enveloped the human spirit. The tenets of the
Truth of the Way of the Lumière Infinie are spelled out in detail on
this web site by the author. Violent acts against individuals due to their
religious beliefs in America is considered a "hate crime."
This web site
in no way condones violence. To the contrary the intent here is to reduce the
violence that is already occurring due to the international corporate cartels
desire to control the human race. The international corporate cartel already
controls the world economic system, corporate media worldwide, the global
industrial military entertainment complex and is responsible for the collapse
of morals, the elevation of self-centered behavior and the destruction of
global ecosystems. Civilization is based on coöperation. Coöperation
does not occur at the point of a gun.
American social mores and values
have declined precipitously over the last century as the corrupt international
cartel has garnered more and more power. This power rests in the ability to
deceive the populace in general through corporate media by pressing emotional
buttons which have been preprogrammed into the population through prior
corporate media psychological operations. The results have been the destruction
of the family and the destruction of social structures that do not adhere to
the corrupt international elites vision of a perfect world. Through distraction
and coercion the direction of thought of the bulk of the population has been
directed toward solutions proposed by the corrupt international elite that
further consolidates their power and which further their purposes.
All
views and opinions presented on this web site are the views and opinions of
individual human men and women that, through their writings, showed the
capacity for intelligent, reasonable, rational, insightful and unpopular
thought. All factual information presented on this web site is believed to be
true and accurate and is presented as originally presented in print media which
may or may not have originally presented the facts truthfully. Opinion and
thoughts have been adapted, edited, corrected, redacted, combined, added to,
re-edited and re-corrected as nearly all opinion and thought has been
throughout time but has been done so in the spirit of the original writer with
the intent of making his or her thoughts and opinions clearer and relevant to
the reader in the present time.
Fair Use Notice
This site may contain
copyrighted material the use of which has not always been specifically
authorized by the copyright owner. We are making such material available in our
efforts to advance understanding of criminal justice, human rights, political,
economic, democratic, scientific, and social justice issues, etc. We believe
this constitutes a 'fair use' of any such copyrighted material as provided for
in section 107 of the US Copyright Law. In accordance with Title 17 U.S.C.
Section 107, the material on this site is distributed without profit to those
who have expressed a prior interest in receiving the included information for
research and educational purposes. For more information see:
www.law.cornell.edu/uscode/17/107.shtml. If you wish to use copyrighted
material from this site for purposes of your own that go beyond 'fair use', you
must obtain permission from the copyright owner. |
 Copyright
© Lawrence Turner
All Rights Reserved
|
