Thepenile raphe is a visible line or ridge oftissue that runs on theventral (urethral) side of thehuman penis beginning from the base of theshaft and ending in theprepuce between thepenile frenulum.[1][2] The line is typically darker than the rest of the shaft skin, even though its shape andpigmentation may vary greatly among males.[1] The penile raphe is part of a broader line in themale reproductive organs, that runs from theanus through theperineum (perineal raphe) and continues to thescrotum and penis, collectively referred to asmedian raphe.[3][4] The penile raphe along with the skin between it arehomologous to the femalelabia minora.[5][6]
The line consists of a subcutaneousfibrous plate, which may vary in prominence and thickness in various areas of the genitals.[7] In the scrotum, the line is located over the internalscrotal septum that divides the two sides of the sac and is densely occupied bynerve fibers.[8] The raphe may become more prominent and darker when the scrotal sac tightens due to contractions. Behind the scrotum, it continues as the perineal raphe. The raphe results as a manifestation of the fusion of thelabioscrotal,urogenital and preputial folds during theembryonic development of the male fetus.[7]
