Abnormal parietal bone morphology Parietal foramina The presence of symmetrical and circular openings (foramina) in the parietal bone ranging in size from a few millimeters to several centimeters wide. Persistent foramina of the parietal bones SNOMEDCT_US:11240000 Enlarged parietal foramina is an inherited condition of impaired skull development. It is characterized by enlarged openings (foramina) in the two bones (parietal bones) that form the top and sides of the skull. This condition is due to problems with bone formation (ossification) within the parietal bones. The openings are symmetrical and circular in shape, with variable size ranging from a few millimeters to several centimeters wide. Parietal foramina are a normal feature of fetal development, but they usually close by the fifth month of pregnancy. Symmetrical, oval defects in the parietal bone Symmetrical, oval parietal bone defects UMLS:C0222706 UMLS:C4280556 HP:0002695 Openings in parietal bones HP:0002697 SNOMEDCT_US:29307005 Holes in parietal bones