Volume 1

The microscopic anatomy of the human body, in health and disease. Illustrated with numerous drawings in colour / By Arthur Hill Hassall, M.B.

  • Hassall, Arthur Hill, 1817-1894.
Date:
1849
Catalogue details

Licence: Public Domain Mark

Credit: The microscopic anatomy of the human body, in health and disease. Illustrated with numerous drawings in colour / By Arthur Hill Hassall, M.B. Source: Wellcome Collection.

Provider: This material has been provided by King’s College London. The original may be consulted at King’s College London.

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    Structure of the Nails. “ If a thin vertical section be made lengthways through a finger-nail from its posterior to its anterior or free margin, the external or dorsal surface of that portion of it which was lodged in the groove between the matrix and the semilunar fold of skin projecting from the dorsum of the finger, is seen covered by a thin layer of cuticle, which extends backwards as far as its posterior border, which is generally jagged and uneven, and forwards upon its dorsum. This portion of cuticle is im- mediately continuous with that overhanging the root of the nail, and although it is not inseparably blended with its horny substance, yet it is sufficiently adherent to be carried forward with it during its growth and to remain intimately attached to its dorsal surface until it is worn off by friction or some other mechanical cause. The palmer surface, near to its free border, is also seen covered by cuticle, which in like manner divides into two parts, the one becoming continuous with the cuticle covering the end of the finger; the other passing backwards along the palmer surface of the nail as far as the lunula, where it imperceptibly terminates. This portion of cuticle gradually diminishes in thickness as it extends backwards, and is more intimately connected with the horny part of the nail than was the cuticle on its dorsal surface. Between these layers of cuticle the proper or horny matter of the nail can be distinguished, pre- senting fine, nearly parallel, and generally semi-elliptical lines, with their concavity looking in different directions in different parts of the same section, and also a multitude of darkish-looking corpuscles, when viewed by transmitted light, of various forms and sizes. These compose the substance of the horn of the nail, and the lines are the cut edges of the lamina; of which it is made up. The horny part of the nail does not increase in thickness after it has extended beyond the lunula, the ap- parent increase of the nail anterior to this point being derived from the cuticle formed upon the anterior part of the matrix. The Matrix of the Nail. “ A mere inspection, even in the living subject, of the parts situated beneath the nail, is, in consequence of its transparency, sufficient to give a general idea of the relative vascularity of the various parts of its matrix. The upper part of the matrix is seen to present a pale, semi- lunar space, called the lunula. The greater part of the lunula is con- cealed by the semilunar fold of integument which projects over it; but extending a little below this fold the lower portion of the lunula is visible, presenting a curved border, with its convexity looking down- wards. Immediately below the lunula, and circumscribing its inferior