FLEXURES OF THE PALM AND SOLE 



171 



muscles moving the joints which underlie them, and are often 

 called " flexion -lines." They are "folds so disposed that the 

 thick skin shall be capable of bending in grasping while it at the 

 same time requires to be tightly bound down to the skeleton of 

 the hands and feet, so as to prevent slipping of the skin which would 

 necessarily lead to insecurity of prehension, just as the quilting 

 and buttoning down of the covers of furniture by upholsterers 

 keeps them from slipping. For this purpose the skin is tied by 

 fibres of white fibrillar 

 tissue to the deep 

 layer of the dermis 

 along the lateral and 

 lower edges of the 

 palmar fascia and to 

 the sheaths of the 

 flexor tendons. The 

 folds, therefore, which 

 are disposed for the 

 purpose of making the 

 grasp secure, vary with 

 the relative lengths of 

 the metacarpal bones, 

 with the mutual rela- 

 tions of the sheaths 

 of the tendons and 

 the edge of the 

 palmar and plantar 



fascia The 



sulci are emphasised 

 because the subcu- 

 taneous fat, which is 

 copious in order to 

 pad the skin for the 

 purpose of holding, 

 being restricted to 

 the interval between 

 the lines along which 



the skin is tied down, makes these intervals project, and 

 these are the monteculi." 1 



This account of them from a leading anatomist shows that 

 not for nothing have these creases been evolved. They are 

 inherited, have an important function and are worthy of study in 



1. A. Macalister, Palmistry Encycl. Brit., 11th Edition. 



Fig. 71. — Flexures on palm of right hand. 

 Drawing made from impression. 



