The primary ossification center for the pubic bone usually appears in the superior ramus between the fourth and sixth fetal lunar months (1, 3, 5, 10). It was detected roentgenographically in all fetuses of 340 mm. length (full term) in the series of 640 specimens reported by Francis (3). Obata (7) and Rambaud and Renault (8) described the early center as bean-shaped and usually situated near the margin of the obturator foramen. One gains the impression from the literature that the pubic cartilage is progressively ossified evenly in a single mass (Fig. 1), until the entire pubic bone is mineralized and becomes fused with the ilium above and the ischium below. Hess (5), however, describes a single instance in which two ossification centers were found in one pubic bone, early. In a study of roentgenograms of the pelves of 1,286 randomly selected newborn infants, we have found a variety of patterns of ossification of the pubic bone, with considerable differences in shape and size. We have arbitrarily classif...