. Human physiology (Volume 1) . responding sideof the body. As yet, only one limb has advanced. The base ofsustentation has been modified, but there has been no limb, remaining behind, has now to be raised and brought for-ward, so as to pass the other, or to be on the same line with it, asthe case may be ; and this finishes the step. In order to bring upthe limb, which is behind, the foot must be successively detachedfrom the soil, from the heel to the toe. In this way, an elongationof the limb is produced, which assists in advancing the correspond-ing side of the trunk, and ex
. Human physiology (Volume 1) . responding sideof the body. As yet, only one limb has advanced. The base ofsustentation has been modified, but there has been no limb, remaining behind, has now to be raised and brought for-ward, so as to pass the other, or to be on the same line with it, asthe case may be ; and this finishes the step. In order to bring upthe limb, which is behind, the foot must be successively detachedfrom the soil, from the heel to the toe. In this way, an elongationof the limb is produced, which assists in advancing the correspond-ing side of the trunk, and excites the rotation of the pelvis on thehead of the thigh bone first carried forward. A succession of thesemovements constitutes walking; the essence of which consists inthe heads of the thigh bones forming fixed points, on which thepelvis turns alternately, as upon a pivot, describing arcs of circles,which are more extensive in proportion to the size of the in a straight line requires, that the arcs of circles de-. WALKING. 405 scribed by the pelvis, and the extension of the limbs when carriedforward, shall be equal; otherwise, the body will be directed to-wards the side opposite to that of the limb, whose movements aremore extensive. Without the aid of vision, it would be imprac-ticable for us to make the arcs equal; or, in other words, to walkstraight forward. Walking backwards differs somewhat from this. The step iscommenced by bending the thigh upon the pelvis, and, at thesame time, the leg upon the thigh. The extension of the thigh onthe pelvis succeeds, and the whole limb is carried backwards, theleg is afterwards extended upon the thigh, the point of the foot isbrought to the ground, and the remainder of its under surface insuccession. The other foot is then raised on its point, by whichthe corresponding limb is elongated; the pelvis, being pushedbackwards, makes a rotation on the limb which is behind, and is,by the action of appropriate muscles, carried on
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Keywords: ., bookcentury1800, bookdecade1840, booksubjectphysiology, bookyear1
