Talk:Cloaca Development

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Cite this page: Hill, M.A. (2021, July 31) Embryology Cloaca Development. Retrieved from


The development of the cloaca in the human embryo

J Anat. 2018 Dec;233(6):724-739. doi: 10.1111/joa.12882. Epub 2018 Oct 7.

Kruepunga N1,2, Hikspoors JPJM1, Mekonen HK1, Mommen GMC1, Meemon K2, Weerachatyanukul W2, Asuvapongpatana S2, Eleonore Köhler S1, Lamers WH1,3.


Subdivision of cloaca into urogenital and anorectal passages has remained controversial because of disagreements about the identity and role of the septum developing between both passages. This study aimed to clarify the development of the cloaca using a quantitative 3D morphological approach in human embryos of 4-10 post-fertilisation weeks. Embryos were visualised with Amira 3D-reconstruction and Cinema 4D-remodelling software. Distances between landmarks were computed with Amira3D software. Our main finding was a pronounced difference in growth between rapidly expanding central and ventral parts, and slowly or non-growing cranial and dorsal parts. The entrance of the Wolffian duct into the cloaca proved a stable landmark that remained linked to the position of vertebra S3. Suppressed growth in the cranial cloaca resulted in an apparent craniodorsal migration of the entrance of the Wolffian duct, while suppressed growth in the dorsal cloaca changed the entrance of the hindgut from cranial to dorsal on the cloaca. Transformation of this 'end-to-end' into an 'end-to-side' junction produced temporary 'lateral (Rathke's) folds'. The persistent difference in dorsoventral growth straightened the embryonic caudal body axis and concomitantly extended the frontally oriented 'urorectal (Tourneux's) septum' caudally between the ventral urogenital and dorsal anorectal parts of the cloaca. The dorsoventral growth difference also divided the cloacal membrane into a well-developed ventral urethral plate and a thin dorsal cloacal membrane proper, which ruptured at 6.5 weeks. The expansion of the pericloacal mesenchyme followed the dorsoventral growth difference and produced the genital tubercle. Dysregulation of dorsal cloacal development is probably an important cause of anorectal malformations: too little regressive development may result in anorectal agenesis, and too much regression in stenosis or atresia of the remaining part of the dorsal cloaca. KEYWORDS: 3D morphometry; anorectum; bladder; urogenital sinus; urorectal septum

Congenital prepubic sinus-An aborted dorsal urethral duplication or a cloacal remnant?

J Pediatr Surg. 2018 Jul 25. pii: S0022-3468(18)30451-2. doi: 10.1016/j.jpedsurg.2018.07.014. [Epub ahead of print]

Nazir Z1, Khan MAM2, Qamar J2.

Abstract BACKGROUND: Congenital Prepubic Sinus (CPS) is an uncommon urogenital anomaly characterized by a blind tract between the skin over the pubis to anterior of the urinary bladder, Urethra or umbilicus. We report four such cases to emphasize varied clinical presentation and embryological conundrum. METHODS: Following Ethical Review Committee (ERC) approval, medical records of pediatric patients (<16 years) presenting with CPS (identified through operating room records and Hospital Information Management System (HIMS) between 1994 and 2018 were reviewed for demographics, clinical presentation, investigations including histopathology, management and outcome. RESULTS: Four cases of CPS, 3 females and 1 male, age range 9 months to 13 years were managed over 25-years. Clinical presentation includes a discharging sinus and recurrent episodes of cellulitis and abscess formation in pubic area and labia majora. Urological investigations were mostly normal. Insertion of lacrimal probe or plastic sheath of intravenous cannula through the sinus opening was useful to determine the course of sinus and aid its excision. Histology of excised sinus highlights the possible embryological origin. CONCLUSIONS: CPS is a rare anomaly with varied clinical presentation. It seems CPS is an aborted urethral duplication (Stephen Type 3) or a Cloacal remnant. Complete excision of the tract in the reported cases was curative. TYPE OF STUDY: Case series. LEVEL OF EVIDENCE: IV. Copyright © 2018 Elsevier Inc. All rights reserved. KEYWORDS: Cloacal membrane; Congenital; Congenital prepubic sinus; Duplication of urethra; Infants and children; Sinus PMID: 30115449 DOI: 10.1016/j.jpedsurg.2018.07.014


Clarification of mammalian cloacal morphogenesis using high-resolution episcopic microscopy

Dev Biol. 2016 Jan 1;409(1):106-113. doi: 10.1016/j.ydbio.2015.10.018. Epub 2015 Oct 17.

Huang YC1, Chen F2, Li X3.


The developmental process through which the cloaca transforms from one hollow structure to two separated urinary and digestive outlets remains controversial and speculative. Here, we use high-resolution episcopic microscopy to examine a comprehensive series of normal and mutant mouse cloaca in which the detailed 3-dimensional (3-D) morphological features are illuminated throughout the development. We provide evidence that the dorsal peri-cloacal mesenchyme (dPCM) remains stationary while other surrounding tissues grow towards it. This causes dramatic changes of spatial relationship among caudal structures and morphological transformation of the cloaca. The 3-D characterizations of Dkk1 mutants reveal a hyperplastic defect of dPCM, which leads to a significant anterior shift of the caudal boundary of the cloaca, premature occlusion of the cloaca and, imperforate anus phenotype. Conversely, Shh knockout causes a severe hypoplastic defect of cloaca mesenchyme including dPCM and persistent cloaca. Collectively, these findings suggest that formation of the dPCM is critical for cloacal morphogenesis and furthermore, growth and movement of the mesenchymal tissues towards the dPCM lead to the cloaca occlusion and separation of the urinary and digestive outlets. KEYWORDS: Bladder; Cloaca; Dkk1; HREM; Shh PMID: 26485363 PMCID: PMC4688061 DOI: 10.1016/j.ydbio.2015.10.018


Spatiotemporal distribution of apoptosis during normal cloacal development in mice

Anat Rec A Discov Mol Cell Evol Biol. 2004 Aug;279(2):761-7.

Sasaki C1, Yamaguchi K, Akita K.


To understand normal cloacal developmental processes, serial sagittal sections of mouse embryos were made every 6 hrs from embryonic day 11.5 (E11.5) to E13.5. During cloacal development to form the urogenital sinus and anorectal canal, fusion of the urorectal septum with the cloacal membrane was not observed, and the ventral and dorsal parts of the cloaca were continuously connected by the canal until disappearance of the cloacal membrane to open the vestibule formed by the urogenital sinus and anorectal canal to the outside at E13.5. Ventral shifting of the dorsal part of the cloaca was observed until E12.5. The dorsal part was transformed in accordance with ventral shifting. In addition, apoptosis was seen to occur around the dorsal part. However, from E12.25, apoptotic cells are observed in a linear arrangement in the urorectal septum just ventral to the peritoneal cavity. Interestingly, extension of this line reaches the area of the cloacal membrane disintegrated by apoptosis. The present findings suggest that in the early stages (until E12.0), distribution of apoptosis in mesenchyme around the dorsal part of the cloaca might be strongly related to the transformation and ventral shifting of this part. Conversely, the apoptosis pattern in urorectal septum mesenchyme in later stages (from E12.0) might be involved in transformation of the urorectal septum and disintegration of the cloacal membrane. PMID: 15278947 DOI: 10.1002/ar.a.20062


O'Connor RJ. An experimental study of the development of the amphibian cloaca. (1940) J Anat. 74(3):301 - 308. PMID 17104815

Stone HB. Imperforate anus with rectovaginal cloaca. (1936) Ann Surg. 104(4): 651-61. PMID 17856859

Imlach F. Case of cloaca in a child. (1875) Trans Edinb Obstet Soc. 3:66-68. PMID 29613532