Klmn M Morphology and histology of the large

Kálmán M: Morphology and histology of the large intestine and rectum To the lectures for EM 1 -8 and 9 -17 on March 21 and 22, 2019. Mainly the parts not emphasized in the textbook.

The main points: The rectum is not ’rectus’ i. e. straight, but S-shaped, the opening directed posteriorly rather than downward! The lower curvature contacts the prostate or the vaginal fornix. The anal canal has 3 parts intestinal (columnar: columnae and sinuses) – intestinal epithalium below it: the pectinate line – epi-ectodermal border hemorrhoidal (venous plexus) stratified squamous epithelium. below it: white line, and a shellow groove (note: at the border of the 2 subdivisions of ext. sphinter, see later) cutaneous keratinized stratified squamous epithelium The anal canal is below the floor of the pelvis (not yet lectured) The external voluntary sphincter onsists of 3 parts: deep, supeficial and subcutaneous. Tha last one is most important. The longitud. smooth has tendon-like elongations, which form connective tissue slings (conjoint fibromuscular layer) around the fascicles of the subcutaneous ext. sphincter) The territories of arteries correspond to the developmental origins: superior rectal (most part) – hindgut derivative middle rectal (small, approx. the sinuses) - cloacal derivative inferior rectal - proctodeum derivative, ectodermal, below the pectinate line.

The Riolan arcades The term ‚small’ or ‚first’ Riolan arch (the anastomosis between the sup. and inf. Pancreaticoduodenal arteries is in use actually only in our institute; it is not applied in the textbooks. The mame ‚arch of Riolan’ is most probably incorrectly applied on the marginal artery; it is the anastomosis – or arch – of Drummond. Which artery was described by Riolan it is already not clear; most probably it was the so-called meandering mesenteric artery, which also interconnects the middle and left colic arteries but in a more proximal and sinuous line. For literature, see the next page. Note: these and similar names of authors (eponymes) are not to be learned by students; we use them only as a homage to the elders.

Papers helping clarify thr ‚Riolan’ question. Only for enthusianistic volunteers! Note: the first one was written by dr. Ágnes Nemeskéri and her co-workers from our institute. Szuák, András; Halász, Vanda; Gáti, Endre; Harsányi, László; Nemeskéri, Ágnes (2016) First Report on Arterial Anastomosis Between Transverse Pancreatic and Left Colic Arteries. Case Studies Journal Vol 5, Issue 2, Page 1 Lange, J. F. , Komen, N. , Akkerman, G. , Nout, E. , Horstmanshoff, H. , Schlesinger, F. , Bonjer, J. , Kleinrensink, G. J. , 2007. Riolan’s arch: confusing, misnomer, and obsolete. A literature survey of the connection(s) between the superior and inferior mesenteric arteries. The American Journal of Surgery. 193, 742 -748. Walter, T. G. , 2009. Mesenteric Vasculature and Collateral Pathways. Semin. Intervent. Radiol. 26(3), 167 -174. Fisher Df, Fry WJ. Collateral Mesenteric Circulation " Surgery, Gyencology and Obstetrics. 1987, 164(5): 487 -492 Gourley EJ, Gering SA. "The Meandering Mesenteric Artery: A Historic Review and Surgical Implications. " Disease of the Colon & Rectum. Vol 48: 5 (2005) pp 9961000 (the figure is taken from this paper). Douard R, Chevallier JM, Delmas V, Cugnenc PH Clinical interest of digestive arterial trunk anastomoses. Surg Radiol Anat. 2006 Jun; 28(3): 219 -27.