DOI Seite / Zitierlink:
https://doi.org/10.11588/diglit.20658#0072
56
ANATOMY.
anatomy of the human body ; otherwise they must have failed in their delineation of its various
actions and attitudes, exclusive of the more difficult expressions of the sensations of the mind.
Several rules have been given, by lecturers on the arts, for ascertaining the depression and
obtrusion of the several muscular parts of the body : they are however perfectly superfluous to
him who has made himself acquainted with the form and situation of the muscular and solid
parts before laid down ; observing this general rule that a muscle, zchtn in a state of action and
consequently contracted in its length, is increased in bulk, and thereby increases the surrounding
parts; and zohen in a state of rest and extended to its full length, its bulk and the surrounding
parts are diminished. This is the unavoidable consequence of the effect of muscular motion,
which is performed by a dilatation in the breadth and consequent contraction in the length of the
muscle, and vice versa. A member therefore by this means acquires an additional bulk: this
appears conspicuously in the arm ; for when both parts of that member lie in the same line, it is
nearly an eighth part of its circumference less than when bent at the elbow ; for the os humeri
withdrawing from the cavity of the cubitus adds the circummensuration of an angle formed by
that motion, to the length of the arm; and this addition is greater or less as the angle made by
bending is more acute or obtuse. The knee however is an exception to this rule.
It may be necessary in this place to notice a few of the most ordinary motions of the members,
which may serve as a clue to the artist, to make his own observations on nature, and which he
should take every opportunity of doing.
The arm being of the most general use is capable, by its articulation at the shoulder, of being
moved in every direction ; the farthest extent of the arm across the stomach brings the elbow
even with the pit of the stomach, whereby the two shoulders and that elbow form an equilateral
triangle. When the two arms are extended behind the back, the elbows are distant from each
other just the length of the fore-arm, from the elbow to the fingers end ; so that the two arms
form a square. This member, when farthest removed from its natural posture, exerts the
greatest force to recover its original station. Thus in throwing a dart or stone the arm is
drawn back, to such a distance from the body as to acquire a rapid motion in returning to its
•natural posture; and the force is greater or less as the arm is drawn more or less backward.
The wrist experiences a change in its dimension from the opening or shutting of the hand.
When the hand is shut it becomes less than when the hand is open; the arm on the contrary
becomes larger when the hand is shut, and less when it is open; the reason is that in opening
the hand the muscles are extended; and when the hand is shut contracted in length, and
thereby dilate the arm. The fingers as well as the toes partake of the customary changes, of
enlarging themselves on all sides when the joints are bent; and suffering a proportionable de-
crease when extended.
The legs are more circumscribed in their motions than the arms. The chief use of these
members being either to support the body or as a mean of walking, their muscles and bones
are much stronger than those of the arms, whereby they are capable of bearing longer and
greater exercise. Their motions are more direct; and to turn the foot or leg outwards or in-
wards requires a motion from the upper part of the os femoris or thigh bone.
The knee is the only joint that is diminished in bending, and augmented in its bulk by being
straightened.
Upon
ANATOMY.
anatomy of the human body ; otherwise they must have failed in their delineation of its various
actions and attitudes, exclusive of the more difficult expressions of the sensations of the mind.
Several rules have been given, by lecturers on the arts, for ascertaining the depression and
obtrusion of the several muscular parts of the body : they are however perfectly superfluous to
him who has made himself acquainted with the form and situation of the muscular and solid
parts before laid down ; observing this general rule that a muscle, zchtn in a state of action and
consequently contracted in its length, is increased in bulk, and thereby increases the surrounding
parts; and zohen in a state of rest and extended to its full length, its bulk and the surrounding
parts are diminished. This is the unavoidable consequence of the effect of muscular motion,
which is performed by a dilatation in the breadth and consequent contraction in the length of the
muscle, and vice versa. A member therefore by this means acquires an additional bulk: this
appears conspicuously in the arm ; for when both parts of that member lie in the same line, it is
nearly an eighth part of its circumference less than when bent at the elbow ; for the os humeri
withdrawing from the cavity of the cubitus adds the circummensuration of an angle formed by
that motion, to the length of the arm; and this addition is greater or less as the angle made by
bending is more acute or obtuse. The knee however is an exception to this rule.
It may be necessary in this place to notice a few of the most ordinary motions of the members,
which may serve as a clue to the artist, to make his own observations on nature, and which he
should take every opportunity of doing.
The arm being of the most general use is capable, by its articulation at the shoulder, of being
moved in every direction ; the farthest extent of the arm across the stomach brings the elbow
even with the pit of the stomach, whereby the two shoulders and that elbow form an equilateral
triangle. When the two arms are extended behind the back, the elbows are distant from each
other just the length of the fore-arm, from the elbow to the fingers end ; so that the two arms
form a square. This member, when farthest removed from its natural posture, exerts the
greatest force to recover its original station. Thus in throwing a dart or stone the arm is
drawn back, to such a distance from the body as to acquire a rapid motion in returning to its
•natural posture; and the force is greater or less as the arm is drawn more or less backward.
The wrist experiences a change in its dimension from the opening or shutting of the hand.
When the hand is shut it becomes less than when the hand is open; the arm on the contrary
becomes larger when the hand is shut, and less when it is open; the reason is that in opening
the hand the muscles are extended; and when the hand is shut contracted in length, and
thereby dilate the arm. The fingers as well as the toes partake of the customary changes, of
enlarging themselves on all sides when the joints are bent; and suffering a proportionable de-
crease when extended.
The legs are more circumscribed in their motions than the arms. The chief use of these
members being either to support the body or as a mean of walking, their muscles and bones
are much stronger than those of the arms, whereby they are capable of bearing longer and
greater exercise. Their motions are more direct; and to turn the foot or leg outwards or in-
wards requires a motion from the upper part of the os femoris or thigh bone.
The knee is the only joint that is diminished in bending, and augmented in its bulk by being
straightened.
Upon