536 



LABORATORY MANUAL OF HUMAN ANATOMY 



PELVIC VISCERA. 



Rectum (Intestinum rectum). 



Dissect the rectum away from the bladder and the prostate. 

 Open the rectum along its anterior wall, pin it down upon a 

 cork dissecting-tray, and study its coats. (Cf. Fig. 288.) 



(a) Mucous membrane (tunica mucosa). (Vide Spalteholz, Fig. 576.) 



(aa) Transverse rectal folds (plicae transversales recti) (0. T. 

 valves of Houston). 



How many do you find? Where is each situated? What 

 is the relation of the folds to the tela submucosa and the 

 muscular wall of the rectum? 

 Lymphatic nodules (noduli lympliatici}. 



(ab) 



Plica transversalis rectU. 



M. sphincter ani tertius 



Tunica mucosa -: 



(Stratum longi-.___ 

 tudinale 

 Stratum circu- 

 lare 



Columnae rectales (Morgagnii).^ 



Sinus rectales.,, 



M. sphincter ani externus<:I 

 M. sphincter ani mternus 



FlG. 288. 



Noduli lym- 



phatici soli- 



tarii 



Plicae mu- 

 cosae 



-'Pars analis recti 



. Annulus haem- 

 orrhoidalis 



~~Integumentum com- 



The tunica mucosa of the lower part of the intestinum rectum and its transition into the integu- 

 mentum commune. (After Toldt, Anat. Atlas, Wien, 1900, 2 Aufl., p. 429, Fig. 712.) 



In the anal part of the rectum (pars analis recti) study 



(ac) Rectal columns of Morgagni (columnae rectales [Mor- 



gagnii]). 



(ad) Rectal sinuses (sinus rectales). 



(ae) Hemorrhoidal ring (annulus haemorrhoidalis) . 



(b) Submucous tela (tela submucosa). 



(c) Muscular coat (tunica muscularis). 



(ca) Longitudinal layer (stratum longitudinale) . 



(caa) Rectococcygeus muscle (M. rectococcygeus). 



(cb) Circular layer (stratum circulare). 



Note that the fibres of the circular layer are in- 

 creased in number in the base of each of the 

 transverse rectal plicae. 



(cba) Internal sphincter muscle of anus (M. sphincter ani 

 internus}. 



