214 SPECIAL ANATOMY. 



of distension), at the sides by the small intestines ; is attached, 

 behind, by mesocolon, and is very moveable. At the commence- 

 ment it rises somewhat upwards and backwards (to muse, iliac, 

 intern, sinist.}, then descends vertically ; the termination curves 

 right or left, forwards or backwards as high as the basis oss. sacri, 

 where the rectum commences. 



Structure. The external surface of the Colon presents, like that of the 

 Caecum, the ttenia and loculamenta. On the Colon descend, and Sigmoid flexure 

 there are only two rows of elevations ; these disappear lower down. 



Mucous and muscular coat (see large intest). 



Serous coat (peritonauni) covers the colon ascendens and descendens on the 

 anterior wall, only, on which account the last is little moveable. On the con- 

 trary the Colon transvers., completely enveloped (mesocolon trans.), and, like 

 sigmoid flexure, is very moveable. 



Vessels : For colon ascend, and right half of transv. branches of Art. mesente- 

 rica superior, Ven. mesent. major for the remainder of the Colon: Jlrt. mesent. 

 infer, and Ven. mesent. minor. 



Lymphatics : open into the glands on the attached border. 



Nerves : Branches of plex. mesentericus sup. et inferior. 



444. c. The Rectum, 



the most inferior part of the intestinal canal, lies on the posterior 

 wall of the lesser pelvis in the curvature before the sacrum and 

 coccyx, commencing to the left of basis oss. sacri, and terminating 

 with the anal opening, anus, under fundus vesicse (or vagina in 

 the female), surrounded and attached all round by uniting tissue. 

 Curved, in front concave and behind convex, it inclines at the 

 apex of the coccyx rather backwards, and is removed from the 

 vagina (in the female) and from the urethra (in the male). Pos- 

 terior surface : above to the left, before the Symphys. sacro-iliaca 

 sinistra, separated by m. pyramidalis, plex. sacral, and vasa 

 hypogastrica, attached by mesorectum, below to the left of os 

 coccyg., covered by m. levator ani. From its middle (on three 

 false vertebrae of the sacrum) to its termination before the middle 

 line. The anterior surface (above free) corresponds in the male : 

 1. To the posterior surface of the urinary bladder (from which it 

 is separated, when filled up, by the small intestines), below to the 

 undus vesicds (separated by the two vesicul. seminales). 2. The 

 Prostata, which projects over one of the two sides or both. 3. 

 The pars membran. urethrse (separated by a triangle, the apex 

 backwards and upwards). In the female : 1. The superior free 

 portion, the lig. latum, Ovarium, tuba Fallopian sinistra, Uterus 

 and Vagina. 2. The inferior part close behind Vagina. 



At the sides are situated, above, small intestines, below, uniting 

 tissue. 



Structure. 1. The mucous membrane is stronger and more red than in 



