The dermis appears in Figure 1 as a nondescript region lying between the epidermis and a region of subcutaneous fat. In reality it is a complex structure held together by a meshwork of structural fibers, for example, collagen, reticulum, and elastin. Most of the space between fibers is filled with a mucopolysaccharidic gel called the ground substance (2). Approximate proportions of these phases are indicated in Table 3. The dermis ranges from about 0.3 mm (300 |im) on the eyelids to about 3 mm in thickness on the back (10). The upper one-fifth or so of the wedge of tissue, the papillary layer by name, is finely structured and provides the support for the delicate capillary plexus that nurtures the epidermis. The papillary dermis merges into a far coarser fibrous matrix, the reticular dermis. This deepest layer of the true skin is the main structural element of the skin. Of considerable importance, the microcirculation that subserves the skin is entirely located in

Table 3 Composition of the Dermis


Approximate % composition


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