ANATOMY


Anatomy of the skin with general consideration homeopathic remedies from the Diseases of the Skin by Frederick Myers Dearborn. …


GENERAL CONSIDERATIONS [General Considerations]

DISEASES OF THE SKIN INCLUDING THE EXANTHEMATA

FOR THE USE OF GENERAL PRACTITIONERS AND ADVANCED STUDENTS BY FREDRICK M. DEARBORN, A.B., M.D.

The skin is a fibroelastic membrane which may be truly called the living envelope of the human body. It is complex in structure and endowed with active and passive functions so that it affords covering and protection to the deeper tissues, and receives impressions from the external world to which it is continually exposed. It is a continuous covering merging into the mucous membranes at all mucocutaneous orifices. It is closely related to the structures beneath through its connective tissue, blood-vessels, nerves and lymphatics.

While the surface is approximately smooth, careful inspection reveals numerous ridges, furrows and pores, variously sized hairs and at the end of the terminal phalanges, hard nail formations. The ridges, just referred to, are caused by the row-like arrangement of the cutaneous papillae and may assume straight, wavy or crescentric lines. The minute depressions known as pores represent the orifices of the follicles and glands of the skin. For the purpose of giving roundness to the angles and curves of the body, and for other more practical reasons, the skin varies greatly in thickness indifferent regions. It is thickest on the buttocks, the palms of the hands and soles of the feet, and thinnest on the eyelids and prepuce. Generally where the areolar tissue is dense and considerable adipose deposit normally exists, the attachment of the skin to the parts beneath is close and firm and its mobility is limited. Where mobility is essential, as around the joints, there is little or no fat and the areolar tissue is loose. Other differences besides that of thickness may be noted as influenced by age, sex, race, health and climate. In fact, there are certain variations in different locations upon the same individual. Thus, the color may range from the fair skin of the blond to the black skin of the negro, from the rosy pink of an infant’s skin to the dark hue of the genitocrural regions of the aged. The patient, which cause the varying color in different races and individuals and under varying circumstances, is located in the deeper protoplasmic areas of the epidermis. The external epidermal layers are composed of transparent flattened epithelial cells which shrivel up into polymorphous scales as they approach the surface and are constantly, although invisibly, thrown off and as constantly renewed from below. It is by this process of continual repair that the epithelial covering of the skin is preserved in a healthy condition by the activity of its own protoplasm. The natural secretion of the skin which continually anoints its surface, making it comparatively impermeable, acts as a passive barrier to a too rapid loss of fluids from within and protects from irritants, variations in temperature and from invasions of bacteria from without.

1. Subcutaneous tissue. 2. Corium. 3. Epidermis. R. Reticular layer of the corium. P (on cut), Papillae of the corium. M, Mucous layer of the epidermis. G. Grandular layer of the epidermis. C. Corneous layer of the epidermis. S. Sebaceous Gland. T (on cut), Sweat-glands. H, Hair. N, Tactile corpuscle. A, B, F, Capillaries supplying fat lobule, sweat-gland, papillae of the hair and papillae of the corium. V, Veins from the papillae of the corium. E, Arrector pili muscles (diagrammatic).

A knowledge of the fundamentals of the anatomy and physiology of the skin is essential in order that the nature of pathological changes in the skin and the curative action of remedies may be understood. Microscopically, the skin is found to be composed of two constant organic parts, the corium and the epidermis. But for practical purposes, a third subdivision, the subcutaneous tissue, is usually described. Several less constant parts such as the sebaceous glands, sweat-glands, hair, nails, pigment, blood-vessels, lymphatics, nerves and muscles must be considered in order to appreciate the complex nature of the skin. For purposes of study, it seems wise to consider the deeper portions before describing those more superficially placed because, by so doing, their mutual relations can be made clearer.

SUBCUTANEOUS TISSUE

(Stratum subcutaneum; Hypoderm)

Most authorities agree that the division of the subcutaneous tissue (1, Fig. 1) from the corium is purely arbitrary with no sharp boundary line. Unna states a patent truth when he says that it owes its recognition as a distinct layer “only to the circumstance that, in consequence of the macroscopically appreciable deposit of fat in it, a distinct border-line is visible even to the naked eye.” The subcutaneous tissue immediately underlines the reticular layer of the corium and, like the latter, is composed of a network of interlacing and anastomosing fibrous connective tissue. These bundles are less densely arranged than in the corium and are attached more or less firmly to the periosteum or superficial fascia, and pass in oblique directions upward and outward to merge in the substance of the corium. The interspaces between these bundles are filled with fat and constitute the panniculus adiposus.

The fat globules are spherical vesicles composed of an elastic capsule with an oval nucleus at one point and a drop of oil filling the remainder of the cavity. They are found clustered in masses forming lobules of varying sizes, separated from one another by delicate fibrous connective tissue and well supplied with blood-vessels, having an afferent artery, one or two efferent veins and a capillary plexus. In some of the thicker portions of the skin, columns of fat (columnae adiposae; fat-columns of Warren) pass obliquely into the lower half of the corium and probably give increased support and elasticity to the skin, assist in the passage of blood-vessels and lymphatics and aid in the nourishment of glands. Subsequent to birth, the fat is gradually absorbed over certain surfaces where mobility or firm attachment are essential such as on the eyelids, in the auricles, on the penis, scrotum and labia minora. The subcutaneous tissue contains sweat-gland coils, the deep hair-follicles, blood and lymph-vessels, nerves, nerve-corpuscles. Under normal conditions this layer gives form and plumpness to the body and serves as a double cushion; first to the parts beneath which are liable to pressure, and second to the more delicate corium externally, as well as the appendages seated within and passing through both layers. In starvation and wasting diseases, the contents of the oil globules disappear, leaving the cell-wall intact, but these rapidly refill with the return of nutrition. An abnormal production and deposit of fat leads to obesity in which the subcutaneous tissue may become an inch or more thick.

CORIUM (Derma; Cutis; Cutis vera; True skin)

The corium (2, Fig. 1) is the most important portion of the skin and, embryonically speaking, it represents the original foundation, in that it is derived from the superficial layer of the mesoderm called the “skin-plate.” At the beginning of the second month of fetal life the cutis is composed of embryonic corpuscles which develop between the second and third months into spindle-shaped bodies of a fibromyxomatous nature. A collagenous substance replaces the tissue just mentioned about the fifth month of embryonic life. Blood-vessels are first noted about the third month.

The corium constitutes the fibroelastic envelope of the body and contains blood-and lymph-vessels, oil-and sweat-glands, hairs, muscles, fat cells and nerves with their various terminal organs. The inter-fascicular spaces are smaller than in the subcutaneous tissue and as they approach the surface, lessen in size. The thickness of the corium varies in different individuals, at different ages and on different parts of the same individual. It is thickest over the palms, soles, back and nates, and thinnest on the prepuce and eyelids. For the sake of convenience, an arbitrary division of the corium may be made into two parts or layers, the reticular and the papillary.

Pars Reticularis (R, Fig.1).- The reticular layer constitutes the bulk of the corium and is composed of white fibrous tissue which, in the deepest portion, separates in bundles without division, forming a distinct net. As the bundles proceed upward, they divide and subdivide, until they reach the upper layer and there form a network by the interlacing of single fibrillae. The larger spaces in the reticular layer are filled with fatty tissue, blood-vessels, nerves, lymphatics, hairs and outwardly opening sweat-ducts. The smaller spaces contain connective tissue corpuscles and wandering cells.

Pars Papillaris. The papillary layer of the corium touches the lowest layer of the epidermis above and extends to just below the basal portion of the papillae. It may be distinguished from the lower or reticular layer by its more intricate structure, the interfasicular spaces being so minute in places that the general aspect is decidedly homogeneous. The innumerable projections or prolongations of the corium into the rete, so-called papillae (P, Fig. 1), give the upper surface of the papillary layer a wavy or zigzag appearance. The gaps in this surface are filled by downward prolongations of the rete which fill up the intervening spaces. A hyalin substance is interposed between the rete and papillae and is supposed to be identical with the cement-like material surrounding and separating the fibrillae of the corium. The papillae may spring each from a single or several from a common base and their apices may be conical, club- shaped or square. They vary greatly in number and size in different regions. There is also much differences as to their disposition, some being arranged in linear series, others in concentric or crescentric shapes causing furrows which apparently cross, often visible to the naked eye as markings upon the surface of the epidermis. They are most highly developed and numerous upon the tips of the fingers, palms, soles, nipples, clitoris, glans penis, and labia minora. It has been estimated that nearly a hundred are developed within each square millimeter of the body surface, and that the whole skin contains from 150 to 200 millions. The importance of the papillae is due to their being the residence of the terminal expansions of the cutaneous nerves and vessels. The vascular papillae are supplied with terminal loops of a minute artery and vein. The nervous papillae contain medullated nerve fibres and one or more tactile corpuscles. Occasionally a papilla is provided with both blood-vessels and nerves.

Frederick Dearborn
Dr Frederick Myers DEARBORN (1876-1960)
American homeopath, he directed several hospitals in New York.
Professor of dermatology.
Served as Lieut. Colonel during the 1st World War.
See his book online: American homeopathy in the world war