TIE

SKULL FROM ABOVE (norma verticalis)  . When looked at from above the frontal bone is seen forming the anterior part of the vertex and articulating with the two parietals posteriorly by a nearly transverse serrated suture (coronal suture) . Running back from the middle of this is the median sagittal suture extending as far as the lambda on the norma occipitalis . The point where the sagittal and coronal sutures join is the bregma, the site of the lozenge-shaped anterior fontanelle in the infant's skull, but this closes during the second year of life . Small ossicles called Wormian bones are often found in the cranial sutures, and one of these (the interfrontal or os anti-epilepticum) is sometimes found at the bregma . About two-thirds of the way back the sagittal suture becomes less serrated and on each side of it the, small parietal foramen may be seen . This only transmits a small emissary vein (see VEINS) in the adult, but, as will be seen later, is of considerable morphological interest . As middle life is reached the cranial sutures tend to become obliterated and the bones can no longer be separated; this fusion begins at the places where the sutures are least deeply serrated, and as a rule the sagittal suture disappears between the two parietal foramina between thirty and forty years of age .