36
SKIN DISEASES OF CHILDREN.
ration is slight even in warm weather. Upon the extensor aspect of the extremities the epidermis presents often a peculiar serpentine appearance, resulting from the cracking of the horny layer into polygonal plates, which in time assume a dirty gray or greenish tint. These plates adhere by the central portion,
![](http://upload.wikimedia.org/wikipedia/commons/thumb/6/64/Skin_Diseases_of_Children_Fig_17_%28page_60_crop%29.jpg/350px-Skin_Diseases_of_Children_Fig_17_%28page_60_crop%29.jpg)
Fig. 17.—Ichthyosis.
while the margin tends to separate from the underlying skin. Around the elbows and knees the natural wrinkles are greatly intensified, and the breaking of the horny epidermis occasions a large number of concentric, whitish lines separating rows of warty elevations. As a rule the flexures of the joints, axillæ, groins, genitals, palms, and soles are but slightly if at all