Primary urethral groove - Mashpedia All-in-One Encyclopedia

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Primary urethral groove
Latin	sulcus urethralis primarius
Precursor	urogenital folds
Gives rise to	urethra
Code	TE E5.6.4.2.1.7.3

The primary urethral groove or urethral groove is a temporary linear indentation on the underside (ventral side) of the male penis during embryonic development.

In humans, it typically appears around 8 weeks of gestation and becomes closed into a normal male urethra by the 12th week.

Pathology [edit]

Failure of complete closure can be associated with hypospadias.^[1]

References [edit]

^ Holland AJ, Smith GH (August 2000). "Effect of the depth and width of the urethral plate on tubularized incised plate urethroplasty". J. Urol. 164 (2): 489–91. doi:10.1016/S0022-5347(05)67408-3. PMID 10893631.

Prenatal development/mammalian embryogenesis, Development of the urinary and reproductive organs (GA 11.1204, TE E5.6-7)

Common urinary and
reproductive system

Mesoderm → Intermediate mesoderm

Mesoderm → Lateral plate mesoderm ("LPM")

Endoderm → Cloaca → Urogenital sinus ("US")

Endoderm+Ectoderm → Cloacal membrane

Urinary system
development

Nephrogenic cord → Kidney

Nephrotome → Pronephros
Mesonephros (Mesonephric tubules)

WD → Ureteric bud + Metanephrogenic blastema

US → Urinary bladder + Urethra + Primary urethral groove + Urachus

Reproductive system
development

Primarily internal	Gonadal ridge → Indifferent gonad → Gonadal cord (Cortical cords, Testis cords) Pronephric duct/Wolffian duct/mesonephric duct + Müllerian duct/paramesonephric ducts (Vaginal plate) US → Prostate or Skene's gland

Primarily external	LPM → Genital tubercle → Labioscrotal swelling → Scrotum or Labia majora LPM → Genital tubercle → Primordial phallus → Penis or Clitoris IM → Gubernaculum Peritoneum → Processus vaginalis or Canal of Nuck