Three-dimensional reconstruction of the anal striated musculature in a human fetus.
Conflicting opinions in the recent literature indicate that the morphological organization and function of the anorectal continence organ has, up to now, not been clearly understood. But a clear imagination of the spatial arrangements of this compound muscle system is of clinical relevance for the pediatric surgeon performing reconstructive surgery. We analyzed 18-microm sections of the pelvic region of 4 human fetuses in order to describe the individual components of this muscle complex. A series of 630 Azan-stained sections was the base for the computer-assisted 3D reconstruction of the levator ani and the external sphincter complex in a male human fetus (14th week p.c.). In this context, special attention was paid to the intermediate muscle layer of the puborectalis which develops ventrally from the funnel-shaped levator ani and joins the tripartite ring system of the sphincter muscle dorsally. Our findings lead to a clear imagination of the spatial arrangement of this intermediate layer and characterize the anorectal muscle complex as an integrated ensemble in which the puborectalis holds a key position.
Fröber
R
R
Institute of Anatomy I, Friedrich Schiller University, Jena, Germany. rfro@mti-n.uni-jena.de
Krebs
U
U
Haas
A
A
Fischer
M S
MS
Schier
F
F
Linss
W
W
D001003:Anal Canal / Q000196:embryology* / Q000473:pathology*; D003198:Computer Simulation; D005260:Female; D005865:Gestational Age; D006801:Humans; D008297:Male; D008953:Models, Anatomic; D018482:Muscle, Skeletal / Q000196:embryology* / Q000473:pathology*