Flaccid Mechanics: From Penis-Size Statistics to Penis-Size Physics

As recently discussed in this blog and elsewhere, a team of UK researchers have published a new study with the scintillating title of Am I normal? A systematic review and construction of nomograms for flaccid and erect penis length and circumference in up to 15521 men.

The first sentence of the paper’s introduction sums things up rather nicely: “The measurement of penis size may be important either in the assessment of men complaining of a small penis or for academic interest.”

In the authors’ own words, their objective was “To systematically review and create nomograms of flaccid and erect penile size measurements.”

The authors of the paper conducted a statistical study of penis sizes in “up to” 15521 men. I found that to be an odd thing about which to be uncertain—were some people too embarrassed by the result to admit being in the study?—but then it turns out to have a simple explanation: there were actually multiple studies and the 15521 men is the number in the largest one. Their methods included a simulation of 20000 observations of penis size from a normal distribution, though it may also have been interesting to consider a heavy-tailed distribution in case of extreme events.

Importantly, one can also go beyond the statistics of penis sizes to consider the physical properties. A penis could be modeled as a continuum, where the properties such as an elastic constant (to measure stiffness, under the assumption that the object is elastic) and other Lamé parameters are different depending on the state of the penis.

The fluid mechanics of urinating has been studied before, so it seems rather natural to also study the solid mechanics of the penis (aka: “flaccid mechanics”).