Archive image from page 472 of The cyclopædia of anatomy and. The cyclopædia of anatomy and physiology cyclopdiaofana03todd Year: 1847 MOTION. 459 they may form the greatest base of support, has been mathematically investigated by Parent and Barthez. According to the latter, the tra- pezium which forms the base of support will be a maximum when the prolongations of the lines drawn through the central line of each foot and passing through the centre of each heel form an angle of 38° 56'. The calculation of Parent is defective, from its being based upon the hypothesis that the foot turns as upo
Archive image from page 472 of The cyclopædia of anatomy and. The cyclopædia of anatomy and physiology cyclopdiaofana03todd Year: 1847 MOTION. 459 they may form the greatest base of support, has been mathematically investigated by Parent and Barthez. According to the latter, the tra- pezium which forms the base of support will be a maximum when the prolongations of the lines drawn through the central line of each foot and passing through the centre of each heel form an angle of 38° 56'. The calculation of Parent is defective, from its being based upon the hypothesis that the foot turns as upon a pivot about its articula- tion with the leg, instead of around the heel. When the body stands erect upon both legs, and presses equally on each, the legs will form equal angles with the vertical line passing through the centre of gravity; but if the two legs form different angles with that line, the pressure upon the legs will be unequal, and will vary with the angles of inclination, for example, in jig. 249, a d is perpendicular and g i parallel to the horizon; if a b Fig. 249. e -— and a g represent the entire force exerted by the legs to support the whole body, a d and a i will be the corresponding portion of these forces necessary to sustain the weight of the body, and will also together represent that weight; and if a d and a i be found by experiment, the absolute forces, a b, a g, will be found. In standing, the limbs serve merely to support the body, and to preserve the centre of gravity at a certain height above the plane of position, within the base of support, which is a necessary condition to prevent it from falling. In addi- tion to these functions they translate the trunk, during progression, from point to point, and keep it in equilibrium, in all the varied move- ments and under the action of all the extra- neous forces incidental to See Borelli de motu animal, prop. 138, p. 173. t When a man stands with his centre of gravity at a vertica
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