Studies in functional and analytical craniology. 10. The density of the bony tissue in Nodes and tracts.

Abstract

The skulls of the dog, cat, foetal horse, and Echidna were investigated by means of X-rays with regard to the bone density in various regions. The marked increase in the density of the bony tissue around the nodes and along the tracts was observed. The tracts and nodes were analysed and described in previous papers (cf. Parts I-IX of this series (Tucker 1954a-f, 1955a-c)). As the nodes and tracts are the paths of stresses, the increased density of the bony tissue in them is interpreted functionally; it increases, namely, the resistance of the whole structure to the stresses which originate from mastication. Other areas of high density of bony tissue are located around the foramen magnum and in the petrosal bone. The first is connected with the stresses which originate from the vertebral column and the mass of the whole head as well; the second is related to the development of the internal ear.