"NORMAL" PENIS SIZE

Nomograms representing the range of "normal" penis size measurements across all ages and races may help alleviate anxiety about penis size among male patients and may also be useful for research purposes.

To this end, David Veale, MPhil, MD, FRCPsych, from the Institute of Psychiatry, Psychology and Neuroscience, King's College London Medical School, King's College London, United Kingdom, and colleagues conducted a systematic review of studies measuring penile size in various samples and constructed nomograms for flaccid and erect penis length and circumference.

In total, 17 studies with up to 15,521 males who underwent penis size measurement by health professionals were included in the analysis, and five definitive nomograms for flaccid and erect penis size measurements were developed.

On the basis of the nomograms, the average length of a flaccid penis was 9.16 cm, whereas the average lengths of a flaccid stretched penis and an erect penis, respectively, were 13.24 and 13.12 cm, the investigators report in an article published online March 3 in BJU International. In addition, the average circumference was 9.31 cm for a flaccid penis and 11.66 cm for an erect penis.

"The most consistent and strongest significant correlation was between flaccid stretched or erect length and height, which was found in four studies and ranged from r = 0.21 to 0.31 and in one study was 0.61," the authors report, noting that correlations with other somatometric parameters were either inconsistent or weak.

Penile measurement may be important either in the assessment of men complaining of a small penis or for academic interest. "Men may present to urologists or sexual medicine clinics with a concern with their penis size, despite their size falling within a normal range," the authors explain. In addition to this concern, referred to as small penis anxiety, "[s]ome men who are preoccupied and severely distressed with the size of their penis may be diagnosed with body dysmorphic disorder," they write.

Although all of the studies included in the review relied on a standardized procedure for measuring penile size, the authors acknowledge the potential risk for bias in the measurements, noting that "temperature, level of arousal, and previous ejaculation could also affect the penile dimensions."

The nomograms may be helpful both "clinically and in research to determine the discrepancy between what a man perceives to be their position on the nomogram and their actual position," the authors write.

"A nomogram may also be used to investigate the tendency for humans to view themselves as better than average (self-enhancement) and to hold a positive bias for socially valued dimensions."

The authors have disclosed no relevant financial relationships.

BJU Int. Published online March 3, 2015.