i6 



SURGICAL APPLIED ANATOMY. [Chap. n. 



always in the middle line, and occur through one 

 or other part of the vertical fissure. Since the upper 

 part of the vertical fissure closes later than the lower 

 part, it follows that the abnormal gap is more often 

 above than below the occipital protuberance. If 

 below the protuberance, the foramen magnum may 

 be opened up, or, on the other hand, the gap may 

 involve the entire bone in the vertical direction. The 



Fig. 4. Back View of Abnormal Skulls, showing Occipital and 



Parietal Bones. 

 A, The "os epactal " ; B, parietal fissures ; c, the sagittal fontanelle. 



lateral fissures may persist, and may simulate fractures, 

 for which they have, indeed, been mistaken ; or they 

 may be so complete as to entirely separate the highest 

 part of the occipital bone from the remainder. The 

 bone so separated is the os e"pactal of the French 

 (Fig. 4 A). 



Parietal fissures. In the developing parietal 

 bone, fibres concerned in ossification radiate towards 

 the periphery from a nucleus about the centre of the 



