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Embryology, Anatomy, and Physiology of the Male Reproductive System
Published in Karl H. Pang, Nadir I. Osman, James W.F. Catto, Christopher R. Chapple, Basic Urological Sciences, 2021
Androgens cause the genital tubercle to lengthen.The mesoderm gives rise to the corpus cavernosa and glans.The ectoderm gives rise to the shaft skin and prepuce.
Surgical treatment of disorders of sexual development
Published in Mark Davenport, James D. Geiger, Nigel J. Hall, Steven S. Rothenberg, Operative Pediatric Surgery, 2020
Rafael V. Pieretti, Patricia K. Donahoe
Penile agenesis occurs in 1 in 30 million births. It appears to be the result of a development failure of the genital tubercle during the fourth week of embryogenesis. The scrotum appears normal and contains normal testicles (Figure 80.22). Patients can present with an imperforate anus and a rectourethral fistula, with a normal anus and a rectourethral fistula, or with the urethra located in the perineum inside a skin tag resembling a foreskin. Patients are otherwise normal 46,XY males.
The urinary and reproductive systems and the external genitalia
Published in Frank J. Dye, Human Life Before Birth, 2019
In the development of a male, the genital tubercle gives rise to the penis. As the penis forms (which involves growth of the genital tubercle and fusion of the urogenital folds), a portion of the urogenital sinus is incorporated into the penis as the penile urethra. Fusion of the labioscrotal swellings gives rise to the scrotum, into which the testes descend during the late fetal period (see Figure 18.8).
The Allantois and Urachus: Histological Study Using Human Embryo and Fetuses
Published in Fetal and Pediatric Pathology, 2022
Xuelai Liu, Xianghui Xie, Zhe-Wu Jin, Huan Wang, Yanbiao Song, Peng Zhao, Long Li
During development, the urogenital sinus is divided into three parts: a cranial part that is continuous with the allantois, a middle pelvic part that becomes the urethra in the bladder neck and the prostatic portion of the urethra in males or the entire urethra in females, and a caudal part that grows toward the genital tubercle [2]. The urinary bladder develops mainly from the cranial part of the urogenital sinus, which is called the allantois. The allantois soon becomes a thick fibrous cord known as the urachus and extends from the apex of the bladder to the umbilicus. The urinary bladder enters the pelvic cavity at about GA 6 weeks, subsequently extending posteriorly along the posterior surface of the anterior abdominal wall and becoming the fibrous remnant of the urachus. In adults, the urachus is represented by a median umbilical ligament, the fibrous remnant of the umbilical arteries [3–5]. In the clinical setting, about 50% of urachal anomalies in infants are present in the inferior part of the urachus, and its lumen is continuous with the cavity of the urinary bladder. This may give rise to urachal sinuses, urachal cysts in children with umbilical recurrent infection and moisture, and patent urachus in children with urine leakage from the urinary bladder to the umbilical orifice. However, the exact anatomical location of allantois/urachus and its correlation with the abdominal wall remain unknown, as is histological information about the allantois/urachus during early phases of normal human development.
Discussion of “Phantom Penis: Extrapolating Neuroscience and Employing Imagination for Trans Male Sexual Embodiment”
Published in Studies in Gender and Sexuality, 2020
Straayer asks us to think about the complex origins of sexual differences, which at a biological level do come from a common origin. Sexual differentiation, in human, and indeed mammalian, embryological development, begins with a “genital tubercle,” which forms in the ventral, caudal region of mammalian embryos of both sexes. In the human fetus, the genital tubercle develops around week 4 of gestation, and by week 9 becomes recognizably either a clitoris or penis. Strayer asks us to consider, even to imagine, the force of pre-embryological and/or pregenetic effects on the developing person. He asks that we think of this work not as definitive but as generative. What can we think about? What can we imagine as embodied life? What constitutes an “errand”?
A case of penile duplication with neonatal teratoma and bladder neck incompetence
Published in Scandinavian Journal of Urology, 2021
Martin Skott, Ulrik Korsgaard, Yazan F. Rawashdeh
Penile duplication is rare, and the embryologic cause is not entirely understood. However, most researchers agree that a defect of the genital tubercle occurs between 23th and 25th day of gestation. The theory holds that the caudal fetal mass of mesoderm is deeply disturbed by trauma, drugs or infection [3,8–10]. Penile duplication is therefore, often accompanied by other anomalies within the urogenital tract (hypospadias, vesicoureteral reflux, hydronephrosis, ectopic kidneys, duplex kidneys, bladder and cloacal extrophy). Additionally, extra-genitourinary abnormalities may also co-exist (colon duplication, vertebral deformities, imperforate anus, ventricular septal defect, polydactyly) [3,7,8].