OF THE SKIN. 



129 



37. Nerves. The skin, in those parts of it which border upon the 

 epidermis, particularly in some localities, is one of the structures most 

 richly provided with nerves in the human organism, whilst in its deeper 

 parts it is remarkable for their scantiness. In the panniculus adiposus, 

 and in the fascia superficialis, as yet, no nerves are known besides those, 

 which, giving off a succession of branches, traverse those parts to reach 

 the corium, or to supply the hair-glands, smooth muscles, and Pacinian 

 corpuscles, of which we shall speak further on. In the corium itself, 

 the trunks which enter through the meshes of the deeper layers ascend 

 by degrees, continually ramify- Fig. 54. 



ing, but without actually form- 

 ing, terminal expansions, to- 

 wards the pars papillaris. Here 

 they anastomose frequently, and 

 form rich terminal plexuses, in 

 which deeper and more superfi- 

 cial portions may be clearly dis- 

 tinguished, the former consist- 

 ing of fine branches still con- 

 taining many primitive tubules, 

 with wide meshes ; the second 

 of fibres single or united in pairs, 

 with narrow meshes. In this last or the fine terminal plexus, there also 

 occur (whether in all the fibres is as yet undecided) in man and in ani- 

 mals actual divisions of the primitive tubules, so that they divide, gene- 

 rally at an acute angle, into two ; and from the plexus itself, the tubules 

 finally enter the base of the papilla? in pairs, in order to run to their 

 extremities, and there unite in a loop. 



The elements of the nerves of the skin exhibit no striking peculi- 

 arities ; the diameter of some, in the trunks in the subcutaneous cellular 

 tissue, is still as much as 0-005-0-006 of a line, and also in the deepest 

 part of the corium, whilst they become finer and finer outwards. In 

 the terminal plexus I find they vary according to the locality, from 

 0-003 to 0-0016, in the papilla from 0-0008-0-002 of a line. In the 

 hand and foot the finest tubules vary between 0-0012-0-002 of a line; 

 in the glans penis, in the lips and nose, on the other hand, only from, 

 0-0008-0-0012 of a line. 



R. Wagner has recently published some statements ("Allg. Zeitung," 

 Jan., Feb., 1852; "Getting. Nachricht," Feb., 1852), according to- 



FIG. 54. Two papilla from the extremities of the fingers, without epithelium and with 

 axile corpuscles, a, and nerves, b. A. Simple papilla, with four nerve-fibres and two termi- 

 nal loops, c. B. Compound papilla, with two vascular points with capillary loops, d; and 

 one nervous point with a terminal loop, e. 



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