CHAPTER VII 



THE DISEASES OF THE EPIPHYSIS (GLANDULA PINEALIS, 

 "ZIKBELDRUSE") [CONARIUM] 



Anatomy and Embryology. The epiphysis originates from an extrusion 

 from the roof of the third ventricle. About the fifth month of fetal life there 

 develops between the posterior commissure and the habenular commissure 

 a thin epithelial extrusion that later thickens and penetrates the mesodermal 

 tissue. The epiphysis in many of the animal classes, for instance the reptiles, 

 is very well developed, and in the developed human being it constitutes a 



.. 

 %,- -* ^- '^-v-i. *-_ : /: 



: - \'\ . ./" \- f > >;:*..;:: v :;; ; -^: 



r - -- : - -*' - " 



. ., 



'..' -:OVv- : ^'; !*.-.:.. . '*V::.!.'v:?. 



; . .' '.-:.- '..'.. X V^- /"v.-'-- 



*'. ..." "".'..*';'*. -.' ','.''-"".:': 



v* .*. .*'.'*. -.'*.*"/.';. '.''"."' 



FIG. 63. Epiphysis of rrtan. 



flat body that arches forward, about i cm. long and 0.5 cm. broad, which by 

 the dorsal lip comes into connection with the habenular commissure and by 

 the ventral with the posterior commissure. Between the two lips the recessus 

 pinealis extends from the third ventricle into the gland. In the new-born it 

 is more spherical, and contains regular follicles with polygonal cells, and, 

 toward the recess, glial tissue. Commencing with the seventeenth year there 

 begin signs of involution, increase of the connective tissue and glia; the fol- 

 licles sometimes form cysts or contain concrements, the so-called brain sand. 



329 



