The urogenital folds (or urogenital ridges, or urethral folds) are an embryological structure which give rise to a portion of the external genitalia.

It differentiates into two structures: ^[1]

• gonadal ridge — medial — primarily reproductive system
• nephrogenic cord — lateral — primarily urinary system

• In the female, the urogenital folds become the labia minora. In contrast, the labia majora are formed by the labioscrotal folds ^[2]
• In the male, they form the spongy urethra and a portion of the shaft of the penis, not including the glans.

In the male, failure of the urogenital folds to fuse during development leads to a condition known as hypospadias.

Less commonly, urogenital fold refers to the fold in the mesonephros which is the precursor of e.g. the suspensory ligament of the ovary^[3]. This is the case in older versions of Gray’s anatomy. See development of the urinary and reproductive organs, particularily the “The Mesonephros, Müllerian Duct, and Genital Gland” section for this meaning.

• Fetal genitalia

• “Development of Male External Genitalia”, at mcgill.ca
• “Development of Female External Genitalia”, at mcgill.ca
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