Size of external genital organs and somatometric parameters among physically normal men younger than 40 years old

To estimate the sizes of the external genital organs in physically normal adult males younger than 40 years old, as well as to correlate the resulting values with age and a number of somatometric parameters, to provide data that could be clinically applicable by the practicing urologist.

Fifty-two physically normal men, 19 to 38 years old, underwent tape measurements of penile dimensions in the flaccid-stretched state (total, shaft, glanular lengths), penile shaft volume calculation, and ultrasonographic testicular volume estimation. The resultant values were correlated with age, height, weight, body mass index, waist/hip ratio, and index finger length.

The mean testicular volume was 16.9 +/- 4.7 cm(3), with the right testis (17.5 +/- 5.8 cm(3)) measuring slightly larger than the left (15.85 +/- 4.9 cm(3); P = not significant). The mean total penile length was 12.18 +/- 1.7 cm, the mean penile shaft length was 7.76 +/- 1.3 cm, the mean glanular length was 4.4 +/- 0.4 cm, and the mean penile shaft volume was 46.5 +/- 17.2 cm(3). Among the various correlations performed, the penile lengths (total, shaft, glanular) to index finger length (P <0.05) and to penile shaft volume (P <0.001) were statistically significant.

Data on the size of the external genital organs among physically normal young adult men were provided and a novel formula for penile shaft volume calculation was proposed. Age and somatometric parameters were not associated with the size of the genitalia, excluding the index finger length, which correlated significantly with the dimensions of the flaccid, maximally stretched, penis.