THE COCCYGEAL BODY. 



i8n 



rior surface the little organ is attached, its long axis lying transverse to that of the 

 blood-vessel. Approached from the posterior surface, the body is found just beneath 

 or within a small opening in the tendinous insertion of the levator ani muscle into the 

 last coccygeal segment, covered by the origin of the external sphincter muscle 

 (Luschka). The dimensions of the organ are small, its transverse and greatest 

 diameter being from 2.5-3mm. and its thickness less than 2 mm. It sometimes is 

 divided into two or even more tiny lobes. The body thus described is, however, 

 only the largest of a series of nodules which includes a variable number of structures, 

 for the most part of minute size, irregularly grouped around the chief mass 

 (Walker). The additional nodules are in many cases connected with the principal 

 body by means of delicate pedicles, in others entirely free, but in all instances they are 

 grouped around the middle sacral artery or its branches. In opposition to the pre- 

 vailing belief, Walker found neither an unusually rich nerve-supply nor intimate 

 connection between the coccygeal body and the sympathetic. 



FIG. 1536. 



Coccygeal gland 



Connective tissue 



r>t-*-sxvm"v ~V*Ji; . \ 





A Capillaries 



Cells 

 Blood-vessels 



Section of human adult coccygeal body. X 220. 



The structure of the body, as seen in transverse sections (Fig. 1536), includes 

 an irregularly oval field of connective tissue, fairly well defined from the surrounding 

 fatty areolar tissue, in which are enclosed numerous aggregations of epithelial cells 

 and, sometimes, a thick-walled artery. The proportion of cell-masses to the connec- 

 tive tissue stroma varies, in some cases the cellular constituents predominating, but 

 commonly the fibrous stroma being the more bulky. The individual cell-groups are 

 uncertainly circumscribed by a slight condensation of the surrounding fibrous stroma. 

 Each aggregation of cells contains a central blood-space, limited by an endothelial 

 wall similar to that of a capillary. Against this wall the epithelial cells lie without 

 the intervention of connective tissue; likewise the cells themselves are closely packed 

 in direct apposition with one another and in consequence present a polygonal con- 

 tour. They are disposed around the central vessel in from two to five layers, the 

 individual cells being indistinctly outlined and composed of clear protoplasm con- 

 taining a relatively large and deeply staining nucleus. Concerning the mooted ques- 

 tion as to the presence of chromaffine cells within the coccygeal body, the testimony 

 of Walker, Schumacher and especially of Stoerk * as to their absence seems convin- 

 cing. The last-named investigator concludes that these cells at no period exhibit the 

 chrome- reaction, and, further and in opposition to JakobssQn, that they have no his- 

 togenetic relation to the sympathetic system. On the other hand, the epithelial 

 character of the cells, their intimate relation to the blood-vessels, and the absence of 



1 Archiv f. mikros. Anatomic, Bd. 69, 1906. 



