NERVE-TERMINATIONS. 



loiy 



Fig. 870. 



Fig. 871. 



Genital corpuscle from integument 

 of penis ; nerve divides before piercing 

 capsule and terminates in intricate end- 

 windings. (Dogiel.) 



Genital corpuscle from integ- 

 ument of human clitoris. X 350. 

 ( IVorihmann. ) 



Fig. 872. 



The Genital Corpuscles. — These endings, most numerous (from one to four 

 to the square miUimeter) in the deeper strata of the corium covering the glans penis 

 and clitoridis, but occurring also in the neighboring parts of the genitaha, are of 

 irregular oval or lobulated 

 outline and from .02 to .35 

 mm. in diameter. They 

 present the same general 

 architecture as the end- 

 bulbs, but are of larger size, 

 possess a somewhat thicker 

 capsule, and contain a more 

 intricate interlacement of 

 the terminal nerve-fibrillae. 

 The latter are derived from 

 the subdivision of two or 

 three meduUated fibres that 

 enter near the base of the 

 corpuscle and are beset with 

 varicosities and club-shaped 

 terminal enlargements. 

 The fibrous capsule, consisting of several connective tissue lamellae possessing flat- 

 tened fusiform nuclei, encloses the semifluid or granular interfibrillar substance in 

 which the end-arborizations are embedded. 



The Corpuscles of Meissner. — In man these 'are most numerous in the 

 corium of the skin covering the flexor surface of the fingers and toes. They are also 

 found in other regions possessing sensibility in a high degree, such as the lips, 

 margin of the eyelid, nipple, penis and clitoris, as well as on the dorsum of the hand 



and foot and the radial surface of the forearm. 

 On the volar surface of the distal phalanx of the 

 fingers, where they occur in greatest numbers, 

 some twenty are found to the square millimeter 

 (Meissner). The corpuscles occupy the summit 

 of the papillae and ridges of the connective tissue 

 stratum of the skin, and lie close beneath the 

 cuticle, with their long axes perpendicular to the 

 latter. In shape they are elongated irregular 

 ellipsoids, often somewhat sinuous in outline, 

 and in the larger papillae may be joined at the 

 deeper end with others to form a compound 

 corpuscle. They are relatively large, being from 

 .12-. 18 mm. long and about one-third as wide. 

 Depending upon the size, each corpuscle is sup- 

 plied by one or more nerve-fibres which enter in 

 the vicinity of the base, as the deeper end is 

 called, and, on piercing the capsule and losing 

 the medullary sheath, divide into a number of 

 naked axis-cylinders. These pass across the 

 corpuscle in parallel or spiral windings and are 

 beset with fusiform and pyriform varicosities, 

 similar enlargements marking the ends of the 

 terminal threads. The entire fibrillar interlace- 

 ment is embedded within a semifluid substance 

 and enclosed by a thin nucleated fibrous capsule. 

 The Corpuscles of Ruffini. — These end- 

 ings are also found within the skin, but at deeper levels, near and sometimes within 

 the subcorium. They are of large size, sometimes measuring as much as 1.35 mm. 

 in length, and of an elongated fusiform contour. The nerve-fibres, often two or 

 more, which usually join the capsule on the side, less frequently near one end, retain 

 the medullary sheath for some distance after penetrating the capsule and throughout 





>^ 



V ;ji 



Corpuscle of Meissner lying within papilla 

 of corium of skin from finger; only deeper 

 layers of overlying epidermis are shown; n, 

 entering nerve-fibre. X 270. 



