Original Research
International Journal of Impotence Research (2005) 17, 191–195. doi:10.1038/sj.ijir.3901272 Published online 28 October 2004
Penile measurements in normal adult Jordanians and in patients with erectile dysfunction
1. 1Department of Urology, Jordan University Hospital, Amman, Jordan
2. 2Jordan Center for the Treatment of Erectile Dysfunction, Amman, Jordan
3. 3National Center for Diabetes, Endocrinology and Genetics, Amman, Jordan
Correspondence: Z Awwad, Urology, Jordan University Hospital, Queen Rania Street, PO Box 13046, Amman, Jordan. E-mail: zawwad@yahoo.com
Received 2 April 2004; Revised 21 September 2004; Accepted 21 September 2004; Published online 28 October 2004.
Abstract
The purpose of this work was to determine penile size in adult normal (group one, 271) and impotent (group two, 109) Jordanian patients. Heights of the patients, the flaccid and fully stretched penile lengths were measured in centimeters in both groups. Midshaft circumference in the flaccid state was recorded in group one. Penile length in the fully erect penis was measured in group two. In group one mean midshaft circumference was 8.98 1.4, mean flaccid length was mean 9.3 1.9, and mean stretched length was 13.5 2.3. In group two, mean flaccid length was 7.7 1.3, and mean stretched length was 11.6 1.4. The mean of fully erect penile length after trimex injection was 11.8 1.5. In group 1 there was no correlation between height and flaccid length or stretched length, but there was a significant correlation between height and midpoint circumference, flaccid and stretched lengths, and between stretched lengths and midpoint circumference. In group 2 there was no correlation between height and flaccid, stretched, or fully erect lengths. On the other hand, there was a significant correlation between the flaccid, stretched and fully erect lengths. Comparing group 1 and group 2, the patients in group 1 were slightly older than in group 2 (P=0.035), but there was no significant difference in their height. However, there was a significant difference regarding the mean flaccid length 9.3 vs 7.7 (P=0.001), and the mean stretched length 13.5 vs 11.6 (P=0.000). We divided both groups into those who are less than 40 y of age, and over 40 y old. There was no statistical difference in the stretched and flaccid lengths between the younger and older individuals in each group. However, when we compared the stretched and flaccid lengths in those of less than 40 y old in group 1 and 2, a significant difference was noticed. Similarly, a significant difference in the stretched and flaccid lengths in those patients over 40 y of age was also present.
Keywords:
penis, measurement, Jordan
Introduction
Penile size is often associated with much interest in different cultures including the Arab culture. Larger size is perceived to validate sexual function and fertility potential, although a recent study showed that only one-third of women attach substantial importance to the size of the male sexual organ.1 Clinicians especially urologists are confronted by questions regarding the normal penile dimensions as well as the relation to different parts of the body such as foot size.2
The knowledge of what normal penile size is has become more important in the presence of demand for penile lengthening procedures.3 Moreover, penile size might be important in the manufacturing of condoms.4
Several studies regarding phallic size have been published.3, 5, 6 The aim of this study is to report penile measurements in two groups of adult Jordanian populations. The first group is of normal individuals, while the second group is of patients with erectile dysfunction as well as to compare our results with previously published data.
Patients and methods
Individuals included in group one were patients aged 17 y and older attending urology clinic for reasons other than erectile dysfunction.
Individuals of the second group were patients attending Jordan specialized center for the treatment of erectile dysfunction. Patients in both groups were further subdivided into those who are below 40 y of age and those over 40 y.
Patients with hormonal or chromosomal abnormality as well as patients with previous history of congenital penile problems, surgery or Peronyie's disease were excluded from the study.
Verbal consent was obtained from all patients. Height of the patients in both groups was recorded. Penile measurements were taken immediately after the patient undressed to minimize the effect of temperature and touch on penile size. The measurements were taken while the patients were lying down and the legs slightly abducted. The flaccid and fully stretched penile lengths were measured in both groups. In addition, midshaft circumference in the flaccid state was measured in group one, and in the second group, penile length in the fully erect penis was measured. Full erection state was achieved using intracavernosal injection of trimex (each 1 ml of trimex is composed of papaverine 30 mg, phentolamine 1 mg, and prostaglandin 10 g). The dose of trimex ranging from 0.1 to 0.4 ml. Patients who did not achieve full nonbendable erection were excluded from the study.
A measuring tape was used to measure the length, and the midshaft circumference of the penis. The starting point was on the dorsal aspect of the penis at its base at the pubic–penile skin junction, pushing the prepubic fat pad against the pubic bone as described by Wessels et al,3 while the tip of the penis was the other reference point.
Measurements were taken by the two urologists, and endocrinologist involved in the investigation for group one and two, and each one was instructed on the same and exact method of measurement. In addition, several measurements were repeated by two investigators on different visits and found to be similar. All measurements were approximated to the nearest 0.5 cm.
Statistical analysis
Data management and statistical analysis
Data were entered and analyzed using EPI info version 6. Initially, range and logical checks were performed on the data. Defected errors were corrected by returning to original data forms.
The stretched and flaccid penile length was compared between the group with and without erectile dysfunction. Statistical significance of obscene difference was assessed using the two-sample independent t-test.
Statistical analysis by age was also performed to remove the possible effect of age on these companions correlation between height, penile length, and midpoint circumference.
Results
A total of 271 patients were included in group one (mean age 44.6 16.3) y, range (17–83). Table 1 shows the clinical characteristics and measurements of group one.
Table 1. Clinical characteristics and measurements of Group1 (271 patients)
| Variable | Mean+s.d. | Range |
| Age (y) | 44.6 | 17−83 |
| Height (cm) | 171.6 | 150−195 |
| Length stretch (cm) | 13.5 | 7.5−20 |
| Length flaccid (cm) | 9.3 | 4.0−15 |
| Circumference mid (cm) | 8.9 | 2.0−12 |
In group two, 109 patients were included (mean age 41 11.7) y (range 22–68). Table 2 shows the clinical characteristics and measurements of this group.
Table 2. Clinical characteristics and measurements of Group 2 (109 patients)
| Variable | Mean | Range |
| Age (y) | 41.0 | 22−68 |
| Height (cm) | 171.5 | 153−190 |
| Length stretch (cm) | 11.6 | 8.0−15 |
| Length flaccid (cm) | 7.7 | 4.0−10 |
| Fully erected (cm) | 11.8 | 8−16 |
| Duration ED (weeks) | 154.6 | 1−1300 |
ED: erectile dysfunction.
In group 1, there was no correlation between height and flaccid length (r=0.03, P>0.05) or stretched length (r=0.05, P>0.05). On the other hand, there was a significant correlation between height and midpoint circumference (r=0.14, P<0.05). There was also a significant correlation between flaccid and stretched lengths (r=0.60, P<0.05), and between stretched lengths and midpoint circumference (r=0.30. P<0.05) as shown in Table 3.
Table 3. Correlation between variables in Group I
| Variable | r | P-value | 95% CL |
| Height+flaccid length | 0.03 | NS | -0.15<r<0.09 |
| Height+stretch length | 0.05 | NS | -0.07<r<0.17 |
| Height+midpoint circumference | 0.14 | <0.05 | 0.01<r<0.25 |
| Stretch+midpoint circumference | 0.30 | <0.05 | 0.18<r<0.04 |
| Stretch length+flaccid length | 0.60 | <0.05 | 0.53<r<0.68 |
NS: not significant.
In group 2, there was no correlation between height and flaccid length (r=0.04, P>0.05), stretched length (r=0.04, P>0.05), or fully erect length (r=0.17, P>0.05). On the other hand, there was a significant correlation between the flaccid and stretched lengths (r=0.65, P<0.05), the flaccid and fully erect length after trimex injection (r=0.44, P<0.05), and the stretched and fully erect length (r=0.51, P<0.05) (Table 4).
Table 4. Correlation between variables in Group 2
| Variable | r | P-value | 95% CL |
| Height+flaccid length | 0.04 | NS | -0.23<r<0.15 |
| Height+stretch length | 0.04 | NS | -0.22<r<0.15 |
| Height+fully erect | 0.14 | NS | -0.32<r<0.05 |
| Flaccid+fully erected | 0.44 | <0.05 | 0.27<r<0.58 |
| Stretch+fully erected | 0.51 | <0.05 | 0.36<r<0.64 |
| Flaccid+stretch length | 0.65 | <0.05 | 0.52<r<0.74 |
NS: not significant.
Comparing group 1 and group 2, the patients in the first group were slightly older than in group 2 (P=0.035), but there was no significant difference in their height. There was a significant difference regarding the mean flaccid length 9.3 vs 7.7 (P=0.001), and the mean stretched length 13.5 vs 11.6 (P=0.000) (Table 5).
Table 5. Differences between the two groups
| Group 1 | Group 2 | P-value | |
| Mean | Mean | ||
| Age | 44.6 | 40.0 | 0.035 |
| Flaccid length | 9.3 | 7.7 | 0.001 |
| Stretch length | 13.5 | 11.6 | 0.000 |
| Height | 171.7 | 171.5 | 0.8 |
The two groups were further divided into those less than 40 and more than 40 y old. No statistical difference was reported in the stretched and flaccid lengths between the younger and older individuals in each group. However, when we compared the stretched and flaccid lengths in those less than 40 y old in group 1 and 2, there was a significant difference. Similarly, there was a significant difference in the stretched and flaccid lengths in those patients more than 40 y old (Table 6).
Table 6. Stretched and flaccid penile lengths of both groups by age
| Age group | Stretch length | Flaccid length | ||
| Mean | P-value | Mean | P-value | |
| <40 | ||||
| ED- | 13.5 (2.1) | 0.001 | 9.2 (1.7) | 0.000 |
| ED+ | 11.8 (1.5) | 7.8 (1.2) | ||
| >40 | ||||
| ED- | 13.6 (2.5) | 0.000 | 9.5 (2.1) | 0.000 |
| ED+ | 11.5 (1.3) | 7.6 (1.4) | ||
ED-: without erectile dysfunction; ED+: with erectile dysfunction.
Discussion
The definition of normal penile size is of a considerable interest in the diagnosis and treatment of sexual dysfunction. Furthermore, some patients who are otherwise physically normal seek to validate their sexual function and fertility potential through objective confirmation of normal size of their phallus. Most men who seek penile lengthening surgery overestimate normal penile length, and in one series none of 67 patients complaining of short penis were found to have severely short penis.7
Flaccid and erect length is important, because patient perception of inadequate penile size in either state could be an important factor in asking for penile length or girth enhancement.
Several studies have been published regarding measurements of penile length, but no studies are reported from Arab countries, and in this study we aim to establish normal values for penile lengths in normal Jordanian individuals as well as in patients with erectile dysfunction and to compare it with published data from different ethnic origins.
Penile length is most commonly measured, and is usually estimated from the tip of the penis to the pubic–penile skin junction. Wessells et al3 introduced the term functional penile length by adding the measured fat pad depth to the erect length.
In comparing our results with other investigators (Table 7), Bondil5 reported the longest penile length in the flaccid and stretched states, and though this might be a normal variation, measurements were obtained only after three manual stretches of the penis. The longest erect penile length was reported by Kinsey,8 data analyzed by Jamison and Gebhard,9 although the data might have been biased as the measurements were recorded by the patients. Other studies3, 4, 10, 11 reported mean flaccid length range (8.16–9.22 cm), and stretched length (12.45–12.5 cm). In this study the mean penile lengths were slightly longer at 9.3 and 13.5, respectively.
Table 7. Comparing penile measurements in centimeters by various investigators
| Authors | Date of study | Number of subjects | Age in years (range) | Flaccid length (cm) | Stretched (S), or erect (E) length (cm) | Flaccid midshaft circumference (cm) | Country |
| Kinsey | 1948 | 2770 | 20−59 | 9.7 | 15.5 (E) | NA | USA |
| Bondil | 1992 | 905 | 17−91 | 10.7 | 16.74 (S) | NA | France |
| da Ros | 1994 | 150 | NA | NA | 14.5 (E) | NA | Brazil |
| Wessells | 1996 | 80 | 21−82 | 8.85 | 12.45 (S), 12.89 (E) | USA | |
| Ponchietti | 2001 | 3300 | 17−19 | 9 | 12.5 (S) | 10.0 | Italy |
| Ajmani | 1985 | 320 | 17−23 | 8.16 | NA | 8.83 | Nigeria |
| Schneider | 2001 | 111 | 18−19 | 8.6 | 14.48 (E) | NA | Germany |
| 32 | 40−68 | 9.22 | 14.18 (E) | NA | |||
| Present study | 2003 | 271 (N) | 17−83 | 9.3 | 13.5 (S) | 8.98 | Jordan |
| 109 (ED) | 22−68 | 7.7 | 11.6 (S) | NA |
NA: not available; N: normal; ED: erectile dysfunction.
Not many studies reported on midpoint measurements; however in this study, the main midpoint circumference (8.98 cm) was less than that reported by Ponchietti et al10 at (10 cm), but similar to what was reported by Ajmani et al11 (8.83 cm).
Although some studies reported penile length in young adult males only,10, 11 we included all age groups. Aging is associated with penile tissue stiffness and abnormal corporal compliance.12 Also described in aging men, a decrease in penile extensibility because of the loss of elasticity of the tunica albuginea.5, 13 Despite this, Schneider et al4 found that the erect penile length did not differ significantly in the erect state between young and older men, although younger men had significantly wider penises. In this study, in group one, the stretched length was longer and the width narrower than that reported by Ponchietti et al10 of young Italian males. In addition, we found no significant difference in penile measurements between younger, less than 40 y and older individuals in each group, which is similar to what was reported by Wessells et al.3
Ajmani et al11 reported on penile size in men of African origin and contrary to popular believe flaccid length is shorter, and midpoint circumference is narrower than what is reported by other investigators. When comparing different races, it was found that East Asians penile measurements were statistically lower in comparison to Caucasians.14
In both groups there was no correlation between height and either flaccid or stretched lengths. On the other hand, there was a significant correlation with midpoint circumference in potent men. Ponchietti et al,10 in a subgroup of 325 males, found similar correlation between height and midpoint circumference. In addition, he found that flaccid and stretched penile lengths correlate positively with height, and inversely with weight. Other investigators found no association between somatometric measurements such as height, weight, waist/hip ratio, and BMI, with penile size, and the only positive correlation was with the length of the index finger.15 Shah and Christopher2 looked at relation of penile length to shoe size and found no correlation.
In both groups there were significant correlations between stretched and flaccid lengths. Also, in group two there was a significant correlation between stretched and erect lengths, which is similar to other reports which found that only stretched length predicted the erect length.3, 4 However, we also found significant correlation in impotent men between flaccid and erect lengths.
In this study we compared penile measurements between potent and impotent men. When we compared group two with group one, the penile length in impotent men was significantly shorter in both the flaccid and the stretched states. The mean flaccid length was 7.7 vs 9.3 (P=0.001), and the mean stretched length was 11.6 vs 13.5 (P=0.000). Penile tissue is composed of smooth muscle cells resting on collagen and elastic fibers limited by the tunica albuginea. The integrity of these structures and adequate blood flow (incoming and outgoing) associated with appropriate neurological control are required for normal penile erection. Tumescence results from arterial dilatation and relaxation of smooth muscle cells, which increase blood flow into the dilated lacunar spaces and causes engorgement of the penis.16 The tunica albuginea is nearly entirely composed of collagenous fibers, but also a few elastic fibers can be found. When the tissue is unstretched, the collagen fibers are situated in an undulating arrangement. The elastic fibers are oriented longitudinally and they connect the undulating bundles of collagen fibers. They have the function of bringing the bundles of collagen fibers back to the nondistended position after being stretched.13 Moreira et al17 defined penile extensibility as the difference between the length of the flaccid penis and the penis submitted to a maximal constant stretch. They measured penile extensibility before and after removing the skin and cavernous tissue in 17 cadavers and four patients undergoing penile implantation. They found that the penile extensibility did not correspond to a decrease in the cavernous smooth muscle fibers or to the increase in the amount of fibrous tissue of the corpora cavernosa, which they observed mainly in patients with arterial disease. They concluded that the tunica albugenia is the main determining factor for penile extensibility. The cause of impotence in our patients was mainly psychogenic, neurology, medication, and anxiety. Iacono et al reported the presence of structural disorders in the tunica albuginea of patients suffering from psychogenic, arteriogenic, and venogenic impotence with significant decrease in the elastic fibers in the tunica albuginea of impotent men compared to a control group. The decrease in length in impotent men in this study could be explained by the loss of elastic fibers, and the lack of intermittent stretching in the tunica albuginea, confirming the common saying (if you do not use it you lose it).
Organic impotence in aging men could be due to a venous leakage factor through veins that are situated normally on the distal third of the ventral penile surface.18 The impaired veno-occlusive function of the tunica albuginea is contributed to by the decrease in elastic fibers concentration found in impotent men.19
Wessells et al3 reported on 80 physically normal men evaluated for sexual dysfunction, and recorded erect length at 12.89, which is longer than our patients at 11.8, while schnider et al,4 who compared erect length in young potent and old impotent men, found potent men had longer erect penises though the difference was insignificant. On the other hand, the flaccid penis in impotent men was longer than in potent men. In this study we found that both younger and older impotent men have significantly shorter stretched penile length than potent men.
Conclusion
The average flaccid penile length in adult potent Jordanians is 9.3 1.4 cm, while the stretched length is 13.5 2.3 cm. Patients with erectile dysfunction tend to have significantly shorter penises. There was a significant correlation between height and midpoint circumference, and between flaccid, and stretched lengths in group 1, and between flaccid, stretched, and erect lengths in group 2.
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