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DR MATTHEW YOUNG. 



A median sagittal outline tracing of the skull, previously centred and oriented in 

 the glabella-lambda horizontal plane, is obtained, and on this outline are marked care- 

 full)' the positions of the glabella, bregma, lambda, inion, basion, and prosthion. In 

 this method Klaatsch adopts the glabella-lambda line as his base line, and explains 

 at great length in his paper why he does so. This explanation I will discuss later. 

 Within the outline tracing a quadrilateral figure is devised (fig. 7) with its angles 

 situated at the glabella, bregma, lambda, and basion respectively, and this polygon 

 is divided by the two diagonals being inscribed into four triangles almost invariably 

 right-angled at the centre of the figure according to Klaatsch ; as the latter dis- 



Fig. 7. — Median sagittal tracing of skull No. 26, series K, showing the inserted quadrilateral 

 figure on the sides of which triangles are erected. The values of the various dimensions in this 

 skull are approximately equal to the mean values for the complete series. (For lettering see 

 fig. 8.) 



covered in his experimental examination of skulls, and as he first explained at the 

 Berlin Anatomical Congress, that the angle which the two lines form with one another 

 is either a right angle or shows a deviation of only a few degrees from that value. 

 The point of intersection he named the central point or zentrum. The triangles so 

 formed are known as the inner triangles, and are numbered I, II, III, and IV in fig. 8. 

 On the four sides of the quadrilateral figure as bases are erected triangles which are 

 named the frontal, the parietal, the chief occipital, and the upper facial ; the chief 

 occipital with its vertex at the inion, the upper facial with its vertex at the prosthion, 

 and the frontal and parietal with their vertices on the corresponding arcs at the points 

 on those most distant from the frontal and parietal chords respectively. On the 

 lambda-inion line as base another triangle is erected with its vertex at the point on 

 the lambda-inion arc most distant from the lambda-inion chord. This triangle is 

 named the adjacent occipital triangle. Perpendiculars are dropped from the vertices 



