refers to the rapid growth of the head region compared to the body region during fetal development in general. Specifically, the head and brain comprise around half the body mass in an embryonic fetus. By birth, the ratio is reduced to 1/4. See also cephalo-caudal development.
ANTERIOR-POSTERIOR DEVELOPMENT GRADIENT: “The anterior-posterior development gradient refers to the ratio of head to body mass as a consequence of development and growth. “