I 



AND THEIR FUNCTIONS. 119 



of the face.* According to Aristotle, the front part of the 

 cranium, the sinciput, is developed after birth and is the 

 last bone of the body to harden.! He erroneously believed 

 that the back part of the head, the occiput, was full of air.l 

 This statement v^^ill be briefly discussed in Chapter xii. 



Aristotle says that the cranium of Man has six bones, 

 and that two of these are situated about the ears, and are 

 small compared with the others. § He also says that they 

 are connected by sutures, three usually running into one 

 another in triquetrous manner, in men, and one running 

 round the skull, in women, but that a man's skull had been 

 seen without sutures. || 



The six bones referred to above are the occipital, the 

 parietals, the temporals, and part of the frontal. Aristotle's 

 description of the sutures is incomplete and incorrect. 

 Generally the number and arrangement of the cranial 

 sutures is the same both in men and women. Looking 

 down on the top of a normally developed adult skull, the 

 sagittal suture and the right and left halves of the coronal 

 suture are seen to converge to a point. The description 

 may refer to these, or, assuming the skull to be viewed in 

 back elevation, it may refer, in a similar way, to the sagittal 

 and lambdoid sutures. The chief variations of the sutures 

 are due to their partial obliteration and the presence of a 

 frontal suture continuous with the sagittal. 



Of the few ancient writers who have described the 

 cranial sutures, not one seems to have correctly explained 

 their arrangement. Hippocrates says that it depends on 

 the relative development of prominences at the front and 

 back of the head, and compares the various arrangements 

 to the letters or symbols T, i, I, and X ^. Galen's descrip- 

 tion, in his On the Use of Parts, ix. 7, is similar to that 

 given by Hippocrates. 



Aristotle's statement that a man's skull without sutures 

 had been seen was probably taken from Herodotus, ix. 83, 

 where it is said that, after the battle of Plataea, a skull 

 without sutures and all of one bone was found. The 

 sutures become indistinct in the skulls of old people, but a 

 cranium without sutures is very rarely seen. Instances of 

 obliteration of cranial sutures seem to be most common 



- H. A. i.e. 7 and c. 8, s. 1. f Ibid. i. c. 7. 



I Ibid. i. c. 7, i. c. 13, s. 2 ; P. A. ii. c. 10, 6566. 

 § H. A. iii. c. 7, s, 2. |1 Ibid. i. c. 7, iii. c. 7, p. 2, 



fl Oil Wounds in the Head, c. 1. 



