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MAMMALIAN ANATOMY 



VARIATIONS IN FORM AND DEVELOPMENT. 



The tibia exhibits variations in the degree of antero-posterior 

 curvature and in the amount of sigmoid twist from its longitudinal 

 axis. The upper part of the anterior border may be very prominent, 

 or it may be so far reduced that 011 transverse section that part of the 

 tibia appears more broadly triangular. The upper part of the internal 

 surface, which normally is quite flat, is sometimes decidedly concave 

 from before backward. The area of insertion of the internal lateral 

 ligament may be elevated into a ridge. Not infrequently the external 



