Fetal head - displaying bones, fontanelles, and average measurements at 9 months of gestation

The fontanelles (or fontanels) of the fetal skull are critical anatomical features during vaginal birth. These allow the cranial bones to move around such that the newborn often resembles a Conehead right after birth - but the look is a good thing! The funky look usually goes away within the first day or two, and this weird pointy head is the primary reason that mom could push that watermelon-sized baby through a pelvic opening that could ordinarily not even accommodate a large mango.

The mastoid, sphenoidal, and posterior fontanelle generally disappear by six months of age, while the larger anterior fontanelle can take up to two years to grow into bone. A sunken fontanelle is one of the ways to tell if an infant is dehydrated.

An American Text-Book of Obstetrics. Edited by Richard C. Norris and Robert L. Dickinson, 1895.

Normal child's skull