Henry Gray (18251861). Anatomy of the Human Body. 1918.
The Corium, Cutis Vera, Dermis, or True Skin is tough, flexible, and highly elastic. It varies in thickness in different parts of the body. Thus it is very thick in the palms of the hands and soles of the feet; thicker on the posterior aspect of the body than on the front, and on the lateral than on the medial sides of the limbs. In the eyelids, scrotum, and penis it is exceedingly thin and delicate.
It consists of felted connective tissue, with a varying amount of elastic fibers and numerous bloodvessels, lymphatics, and nerves. The connective tissue is arranged in two layers: a deeper or reticular, and a superficial or papillary. Unstriped muscular fibers are found in the superficial layers of the corium, wherever hairs are present, and in the subcutaneous areolar tissue of the scrotum, penis, labia majora, and nipples. In the nipples the fibers are disposed in bands, closely reticulated and arranged in superimposed laminæ.
FIG. 942 The distribution of the bloodvessels in the skin of the sole of the foot. (Spalteholz.) (See enlarged image)
The reticular layer (stratum reticulare; deep layer) consists of strong interlacing bands, composed chiefly of white fibrous tissue, but containing some fibers of yellow elastic tissue, which vary in number in different parts; and connective-tissue corpuscles, which are often to be found flattened against the white fibrous tissue bundles. Toward the attached surface the fasciculi are large and coarse, and the areolæ left by their interlacement are large, and occupied by adipose tissue and sweat glands. Below the reticular layer is the subcutaneous areolar tissue, which, except in a few situations, contains fat.
The papillary layer (stratum papillare; superficial layer; corpus papillare of the corium) consists of numerous small, highly sensitive, and vascular eminences, the papillæ, which rise perpendicularly from its surface. The papillæ are minute conical eminences, having rounded or blunted extremities, occasionally divided into two or more parts, and are received into corresponding pits on the under surface of the cuticle. On the general surface of the body, more especially in parts endowed with slight sensibility, they are few in number, and exceedingly minute; but in some situations, as upon the palmar surfaces of the hands and fingers, and upon the plantar surfaces of the feet and toes, they are long, of large size, closely aggregated together, and arranged in parallel curved lines, forming the elevated ridges