Urogenital sinus

The fetal testis induces a male type of phenotypic sex development by virtue of producing two sorts of hormones. The first of these is the androgen testosterone, which triggers the formation of male structures from the Wolffian duct, the urogenital sinus, and the external genital primordia, via mechanisms considered below. The second type of fetal testicular hormone is a macromolecule, apparently a glycoprotein, that evokes involution of the Mullerian duct during normal male sex differentiation. 

In the absence of cortisone, the negative feedback on the anterior hypophysis does not operate. Consequently, the hypophysis is induced to secrete ACTH. The high level of ACTH stimulates proliferation of the adrenal cortex, and androgens are secreted in excess. In the female, cortical hyperplasia at birth leads to enlargement of the clitoris, and possibly to a urogenital sinus and an imperforated vagina. Thus, the newborn female is often taken for a male. The victim is a pseudohermaphrodite. Precocious growth of sexual hair, irreducible amenorrhea, and ovarian atrophy will occur in these patients. 

The bladder develops mainly from the vesical part of the urogenital sinus. The trigone region is derived from the caudal end of the mesonephric ducts. 

The epithelium of most of the male urethra and the entire female urethra is derived from endoderm of the urogenital sinus. The distal part of the male urethra is derived from the glandular-urethral-plate. This ectodermal plate grows, becomes canalized, and joins the rest of the spongy urethra. Therefore, the epithelium of the terminal part of the urethra is derived from surface ectoderm. The connective tissue and smooth muscle of the urethra in both sexes is derived from the adjacent splanchnic mesenchyme (Moore and Persaud 1998). 

The epithelium of most of the male urethra and the entire female urethra is derived from the endoderm of the urogenital sinus. The distal part of the male urethra is derived from an ectodermal plate, called the urethral plate. 

Kaufmann-McKusick syndrome Hydrometrocolpos, transverse vaginal membrane, vaginal septum, postaxial polydactyly, cardiac anomalies, hypospadias Hydroureter, ureteral duplication, ectopic urethra, urogenital sinus, posterior urethral valves AR (236700), mutations in Bardet-Biedl type 6 BBS6 gene... 

Lower Urinary Tract Anomalies of Urogenital Sinus 152... 

The process of partitioning then spreads cau-dally into the external cloaca. The perineal mound (i.e., the tip of the urorectal septum) separates the urogenital sinus from the anus. The inner genital folds proliferate to form the perineum and the labia minora, whereas the outer genital folds develop into the labia majora. 

Pediatric radiologists will commonly come across mUllerian duct anomalies at two different stages of a girl s life. In neonates diagnostic requests encompass evaluation of a palpable abdominal mass and delineation of associated genital malformation in urogenital sinus anomalies. In adolescent girls delay in puberty or primary amenorrhea as well as pelvic... 

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