A morphometrical study of human fetal thymus.

A morphometrical study was made of the thymus lobules in the cortical and medullary layers of male and female fetuses, 16 to 31 weeks old, divided into the age groups 16 to 19, 20 to 23, 24 to 27 and 28 to 31 weeks of intrauterine life. Results were correlated with body and thymus weights; the lobular, cortical and medullary volumes, as obtained using a histometrical method, were proportional to thymus, but not body weight increase. No differences were noted in the volumes and weights investigated as a function of fetal sex.