Sagittal Synostosis vs. Prematurity
Left picture: Here, the diagnosis is a synostosis of the sagittal suture. Right picture: The deformity of the twins is due to the prematurity, which is often combined with a scaphocephaly. The latter recovers spontaneously. However, the skull deformity cannot be differentiated from a sagittal synostosis at the beginning if only the appearance of the head is considered.
Both the young infant and the 3.5-month-old twins have an elongated skull with frontal and occipital bossing. Instead of the elongated skull of one twin (picture at the top) the face of the other twin is depicted (picture at the bottom), in which the frontal region is relatively narrow and high. Left picture: In this pathology a bony ridge is palpable over the vertex; the skull index is less than 70. Right picture: In this twin both parietal bones are mobile against each other, and no bony ridge is palpable along the sagittal suture; the history tells us that the shape has ameliorated since birth in the two twins which were born in the 34th week of gestation. However, the skull indexes of 64 and 63, respectively, still lie below the normal value of 70.