Absence of the Parietal Bone
About the first of November, I attended a lady in confinement who was delivered of a boy, perfect in every particular except that the posterior half of the left parietal bone was entirely absent.
My first impression was that it was simply an enlarged fontanelle, but careful observation showed that the margins of the surrounding bone other than those included in the region of the fontanelle were blunt and abrupt and smooth.
There was considerable bulging of the cerebral contents, but there was no evidence of either hydrocephalus, meningocele, or other abnormal conditions, and in the course of three or four weeks the protrusion subsided, and it was evident that bony tissue was forming over the vacant space.
This has continued until the bone is now intact, with no apparent harm to the child, although the new formation of bone is rough and somewhat uneven. The scalp and its covering are perfect. I report this because I have not been able to find the record of a similar case, and the first appearances were certainly not promising.