414 THE SKIK 



parts loose and moveable, in others close and firm, as on the palmar surface of 

 the hand and the sole of the foot, where the skin is fixed to the subjacent 

 fascia by numerous stout fibrous bands, the space between being filled with a firm 

 padding of fat. In some regions of the body the skin is moved by striated muscular 

 fibres, which may be unconnected with fixed parts, as in the case of the orbicular 

 muscle of the mouth, or may be attached beneath to bones or fasciae, like the other 

 cutaneous muscles of the face and neck, and the short palmar muscle of the hand. 



Structure. The cutis vera is made up of an extremely strong and tough 

 framework of interlaced connective tissue fibres. The fibres are chiefly of the white 

 variety, such as constitute the main part of the fibrous and areolar tissues, and are 

 arranged in scout interlacing bundles, except at and near the surface, where the 

 texture of the coriuru becomes finer and closer. "With these are mixed elastic fibres, 

 which vary in amount in different parts, and connective tissue corpuscles, which 

 are often flattened up against the bundles of white fibres. Towards the attached 

 surface the texture becomes much more open, with larger meshes, in which lumps 

 of fat and the sweat-glands are lodged ; and thus the fibrous part of the skin, 

 becoming more and more lax and more mixed with fat, blends gradually with the 

 subcutaneous areolar tissue. 



In consequence of this gradual transition of the corium into the subjacent 

 tissue, its thickness cannot be assigned with perfect precision. As a general rule, it 

 is thicker on the posterior aspect of the head, neck, and trunk, than in front ; and 

 thicker on the outer than on the inner side of the limbs, and as well as the cuticle, 

 it is remarkably thick on the soles of the feet and palms of the hands. The skin of 

 the female is thinner than that of the male. 



The skin is generally said to measure from ^th of an inch to nearly ^th of an inch 

 (5 to 3 millimeters) ; but it has been pointed out by Warren that, on the back and shoulders, 

 it may be as thick as 5 or 6 mm. ; and here it is almost entirely formed of dense anastomosing' 

 bundles of connective tissue, sending down on the one hand fibrous prolongations through 

 the subjacent panniculus adiposus, and being penetrated obliquely on the other hand by 

 columns of fat cells, which extend from that layer to the bases of the small hair-follicles, and 

 conduct blood-vessels to these and to the surface of the skin. 



Bundles of plain muscular tissue are distributed in the substance of the corium 

 wherever hairs occur ; their connection with the latter will be afterwards explained. 

 Muscular bundles of the same kind are found in the subcutaneous tissue of the 

 scrotum, penis, perineum, and areola of the nipple, as well as in the nipple itself. 

 They join to form reticular layers, attached to the under-surface of the corium. 

 In the areola they are disposed circularly. 



For convenience of description it is not unusual to speak of the corium as 

 consisting of two layers, the "reticular" and the "papillary." The former, the 

 more deeply seated, takes no part in the construction of the papillae, but contains in 

 its meshes hair-follicles, cutaneous glands, and fat. The latter is extended into 

 papillae, and receives only the upper portion of the hair-follicles and glands, together 

 with the terminal expansion of the blood-vessels. 



The free surface of the cutis vera is marked in various places with larger or 

 smaller furrows, which also affect the superjacent cuticle. The larger of them are 

 seen opposite the flexures of the joints, as those so well known in the palm of the 

 hand and at the joints of the fingers. The finer furrows intersect each other at 

 various angles, and may be seen almost all over the surface ; they are very 

 conspicuous on the back of the hands. Fine curvilinear ridges, with intervening 

 furrows, mark the skin of the palm and sole ; these are produced by the ranges of 

 papillae, to be immediately described : they form definite patterns, characteristic 

 of each individual, but at the same time capable of being classified under a rela- 

 tively small number of heads. Moreover, these patterns are permanent and do 



