Abstract
With the exception of certain viscera, such as the heart and the liver, all corresponding structures in the body are repeated and reversed symmetrically, i. e., they express the condition of antitropy. Although any two homologous structures, such as the feet, the hands and the cerebral hemispheres, are of comparable constitution, they differ structurally in that one is the mirrored counterpart of the other. Orton1 has held that this antitropic condition exists for function as well as for structure. For example, innervation of certain muscles of the left hand results in an activity which is exactly opposite, in respect to the midline, to that which results from the innervation of corresponding muscles of the right hand. This principle is recognized in the assumption that mirror writing with the left hand is the normal sinistral expression. In the coarser movements of the primary muscles, e. g., those of the extremities,

This publication has 0 references indexed in Scilit: