The role of cartilage canals in the ossification of the talus.

Interrupted serial sections of the foot region from 14 human fetuses, crown-rump (CR) lengths between 32 and 240 mm, were studied, using HE, PAS, Alcian blue, Gomori's trichrome and von Kossa stains. Cartilage canals carrying vascular connective tissue from the perichondrium entered the talus by 68-mm. The centre of ossification developed in the neck region of the talus cartilage by 240 mm CR length, but early stages of chondrocyte proliferation and hypertrophy were noted by 108-mm CR length. The latter is marked by 170 mm CR length. A number of cartilage canals were observed around the developing centre. Branches from these cartilage canals appeared to supply vascular osteogenic tissue to its marrow spaces.