Penile Size and Penile Enlargement Surgery: A Review

B.E. Dillon; N.B. Chama; S.C. Honig


Int J Impot Res. 2008;20(5):519-529. 

In This Article

Penile Size

Paintings and writings by the ancient Greeks, as early as 200 BC suggest that they believed that a smaller penis was superior.[1] However, over the course of time, with the various sexual revolutions this belief has changed and for most men, larger is better and comparisons to the rest of the general population matter. This is evident in the terms 'phallic identity' and 'phallocentrism'. 'Phallic identity', as described by Vardi, is the concept of a man seeking identity in his penis, which a focus on bigger is better. Similarly, 'phallocentrism' is the concept that the penis is central to a man's identity.[3]

Penile size has been suggested to correlate to certain physical characteristics. There has been some data suggesting no correlation between shoe size and penile length by Shah and Christopher in a small 2002 study. They studied 104 men from 54 to 87 years of age. All penises were measured on full stretch and the foot size of each patient was recorded. After linear regression analysis, there was no statistical correlation between stretched penile length and shoe size.[4]

Specifics of measurement of penile size is important in comparing data in different papers. Although there is no standard technique for measuring penile size, there appears to be a consensus among researchers that penile length should be measured on the dorsum of the penis beginning from the pubopenile junction to the tip of the glans (Figure 1).[5] This measurement applies to the flaccid, stretched and erect states. In addition, measurements of penile girth should be obtained from the middle of the penile shaft, in all three states. For the purpose of clarity of nomenclature, a flaccid penis is one that is unstimulated or not aroused, and would be seen when the man is in the normal anatomical position. Flaccid stretched is when the flaccid penis is pulled to its maximal distance. Lastly an erect penis is one that is maximally stimulated, either through visual, tactile or pharmaceutical manipulation.

Penile length from pubopenile skin to meatus and fat pad depth from pubic bone to pubopenile skin. Reprinted with permission from Journal of Urology.

To date, there have been few studies published on penile size. The first reported study was conducted by Loeb in 1899, where he examined 50 subjects, age ranging from 17 to 35 years. He measured the penis only in the flaccid state and found the average size to be 9.41 cm.[6] It was not clearly stated how measurements were made. In 1942, Schonfeld and Bebe looked at the normal variability of penile size, both length and girth of the penis from birth to maturity. With respect to penile length, measurements were recorded only in the stretched state, however they looked at penile girth in both the erect and flaccid conditions. They found that the average stretched length was approximately 13.1 cm (13.26 for 61 men aged 17 years, 13.11 for 71 men aged 18-19 years and 13.02 for 54 men aged 20-25 years). In addition they found the average girth of the flaccid penis (location of measurement not mentioned) to be 8.5 cm, and the average girth of the erect penis to be 15.8 cm.[7]

In 1948, Kinsey published his hallmark paper on penile length, which until 2001 was the largest published series. Kinsey examined men between the ages of 20 and 59 and measured subjects in both the flaccid and the stretched flaccid states. He found that the average flaccid length was 9.7 cm and the average stretched length was 16.74 cm.[8]

Nearly 50 years later in 1992, Bondil et al.[9] studied 905 men from age 17 to 91 years, to examine the 'extensibility' of the penis. Penile length was recorded in three conditions; flaccid, maximal flaccid stretched and flaccid after stretch. The maximal flaccid stretched length was achieved by pulling on the glans three times, allowing for 'tissue viscoelasticity.' After the penis was measured at its maximal flaccid stretched length, it was then remeasured in its flaccid length, which they defined as 'flaccid after stretch'. Lengths were found to be 10.7 and 16.74 cm in the flaccid and stretched states, respectively.[9] They concluded that extensibility decreases with age.

In 1992, da Ros and colleagues published the first series examining the length of the erect penis. The study was conducted in a group of Caucasian men who were interested in penile lengthening. 150 men were enrolled in the study and were given an intracavernosal injection of papaverine and prostaglandin to achieve erection, after which measurements were obtained. Measurements of girth were taken both proximally and distally. The authors found that the average erect length in their 150 subjects was 14.5 cm, proximal girth 11.92 cm and distal girth 11.05 cm.[10] After data were collected, and information was shared about the 'normal' ranges of penile length, men were no longer interested in penile lengthening surgery.

In 1999, Bogaert and Hershberger[11] investigated the relationship between sexual orientation and penile size. The authors had two cohorts, of 935 homosexual men and 4187 heterosexual men with a mean age of 30 in both groups. Self-reported penile length was performed in five measurements; estimated erect size, flaccid penile length, erect penile length, flaccid girth and erect girth. The authors reported that there was a significant difference in both penile length and girth in this self-reported mailed questionnaire population. The average flaccid homosexual penis was 10.41 cm as compared to 9.83 cm for heterosexual men. The average erect penis was 16.40 and 15.60 cm for homosexual men and heterosexual men, respectively. Furthermore, flaccid penile girth measurements were 9.75 cm for homosexuals and 9.40 cm for heterosexuals. Lastly, erect girths measured 12.57 and 12.19 cm in homosexual men and heterosexual men, respectively.[11] The validity of self reported measurements needs to be considered when evaluating these data.

Wessells et al.[5] published their data regarding penile length and indications for penile augmentation. They examined penile lengths in 80 men with a mean age of 54 years. Patients were excluded if they had any penile abnormalities (that is, disease, history of urethroplasty or congenital deformities). Measurements were taken in the flaccid, stretched and erect conditions. Measurements of the erect penis were obtained by injections with prostaglandin E1, and in some cases of incomplete erection phentolamine/papaverine were added to achieve full erection. The average flaccid length was 8.85 cm (s.d.=2.38); average stretched length 12.45 cm (s.d.=2.71) and the average erect length 12.89 cm (s.d.=1.31). Girth was recorded midshaft in the flaccid condition and erect conditions at 9.71 cm (s.d.=1.17) and 12.30 cm (s.d.=1.31), respectfully.[5]

The largest study on penile length was published in 2001 by Ponchietti et al.,[12] with a sample size of 3000 Italian men. The goal of their study was solely to determine the variability in penile size. Subjects ranged from age 17 to 19 years and measurements were recorded in the flaccid and flaccid stretched states. Flaccid circumference was recorded in the middle of the shaft. Mean flaccid length was 9.0 cm (s.d.=2.0), mean stretched length was 12.5 cm (s.d.=2.5) and mean circumference was 10.0 cm (s.d.=0.75).

Schneider et al.[13] looked at the relationship between penile size and problems associated with condom use. Their experimental population consisted of 111 men aged 18-19 years. Measurements were carried out in the flaccid length, and subjects were given calipers to measure penile width, not circumference. The average self reported flaccid penis measured 8.60 cm (s.d.=1.50), whereas the average erect penis was 14.48 cm (s.d.=1.99).[13]

In 2005, Awwad et al.[14] published his series of patients examining penile size in Jordanian men with and without erectile dysfunction. In the 271 'normal' subjects aged 17-83 years, they found that flaccid length was 9.3 cm (s.d.=1.9), stretched length 13.5 cm (s.d.=2.3) and penile girth 8.9 cm (s.d.=1.5). Table 1 summarizes all the aforementioned studies[12] ( Table 1 ).

After reviewing these data, some conclusions can be drawn regarding penile length and girth. With respect to penile length, average penile size is ~9.0-9.5 cm in the flaccid state, whereas the maximally stretched flaccid length is ~14.5-15 cm. Average erect penile length ranges from 12.8 to 14.5 cm and the average penile girth is ~10.0-10.5 cm. What is the significance of these findings? Most of the papers had standard deviations of ~2 with respect to penile length and standard deviations of ~1 when looking at penile girth. By applying these findings, one might be able to assess the patients who are 2 s.d. below the average size. This appears to be the patients who have a flaccid penile length <5 cm, or mid shaft penile girth <8.0 cm.

These data give reconstructive surgeons a starting point as to when penile augmentation might be deemed medically necessary or appropriate.


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