Cart is empty

Male Anatomy

God gave me a brain and a penis, and enough blood to run one at a time. — Robin Williams

The penis has been dubbed “the barometer of a man’s health,” and rightly so, as any abnormality in its anatomy, physiology, or functioning may reflect an underlying disease or disorder. Furthermore, the penis is considered to be the symbol of virility, power, manhood, strength, and authority. This explains the obsession of many men with the size of their penises. In an Internet-based survey of 52,031 heterosexual men, 66% rated their penises as average, 22% as large, and 12% as small (Lever J et al. 2006). Unfortunately, despite the seeming obsession with this vital organ among the majority of men (and quite a few women), most people are ignorant of even the basics of penile function and dysfunction. Here are answers to several frequently asked questions—and perhaps to some you’ve been unable to ask.

What is the Normal Length and Circumference of the Adult Penis?

No so-called normal penis size can be universally applied. Penile dimensions differ according to heredity, race, amount of suprapubic fat, age, and serum testosterone level, and even vary from one country to another.

The medical literature reports that the average length of the healthy adult penis in the United States is 3.5 inches (8.8 cm) when flaccid, about 4.9 inches (12.4 cm) when stretched, and 5.1 inches (12.9 cm) when erect; the average flaccid girth is 3.7 inches (9.4 cm) (Wessells H et al. 1996b). Other reported measurements (Chen J et al. 2000; Ponchietti R et al. 2001; Schneider T et al. 2001; Harding R, Colombok SE 2002; Son H et al. 2003; Syropoulos E et al. 2003; Awwad Z et al. 2005) from various countries follow:

  • Average flaccid length is 3.72 inches for Jordanians, 3.6 inches for Italians, and 2.76 inches for Koreans, and among Germans, 3.68 inches for ages 18-19 and 3.44 inches for ages 40–68.
  • Average stretched length is 5.4 inches for Jordanians, 4.87 inches for Greeks, 5.2–6.12 inches for Britishers, 5 inches for Italians, and 3.84 inches for Koreans.
  • Average erect length ranges from 5.76 inches for Germans to 6.12 inches for British gays.
  • Average flaccid circumference at midshaft ranges from 3.4 inches for Koreans to 4 inches for Italians.

In general, and despite some minor international variations, the normal measurements of the penis are 3.6–4 inches for the flaccid penis, 4.6–5.2 inches for the stretched penis, and 5.6–6.4 inches for the erect penis, with a girth of 3.6–4 inches for the flaccid penis and 4.6–6 inches for the erect penis (Wylie KR, Eardley I 2007).

While the penis is flaccid, the best way to estimate its erect length is to pull back the fat pad that may be covering it, stretch the penis, and measure it from the lower edge of the pubic bone to the tip of the glans.

And before you ask, there is no correlation between the size of the penis and the size of the nose, foot, fingers, or any other body part.

How Important is Penile Size to Women?

There is no shortage of controversy over this issue, especially in the lay press. Some women attribute great importance to penile size, whereas others say they do not care about it, evaluating the quality of their partners’ sexual performance rather than their physical endowments. For the majority of women, it seems that quality matters more than quantity.

In a study from the Netherlands of 170 women asked about the importance of penile size in relation to sexual functioning, performance, and satisfaction, 20% rated length as important and 1% as very important, versus 55% who rated it as unimportant and 22% as totally unimportant. A similar trend emerged for penile girth, which was rated overall as more important than length (Francken AB et al. 2002). Although these findings cannot be generalized to all women worldwide, they may indicate that penile size is important to only the minority—albeit a substantial number—of women.

Unfortunately, many men equate penis size with manhood, virility, sexual power, physical attraction, and better performance. Many even seek penile lengthening, although their organ size is actually within medical norms (see the following section). A candid discussion with his sexual partner may help to alleviate a man’s anxiety regarding his self-assessed “small” penis. Furthermore, the size of a small penis in its flaccid state is usually not really indicative of its erect size, as its dimensions will generally increase during erection more than those of a large flaccid penis will.

Do Men Seeking Penile Lengthening Truly Have a Small Penis?

Most urologists are well aware that despite the concern manifested by many men about small penile size, the organ’s size in the majority of men seeking penile augmentation is actually normal (Lee PA, Reiter EO 2002, Mondaini N et al. 2002). A two-year study at the University of Florence, involving 67 men aged 16-55 who requested surgical lengthening, recently confirmed this observation. Although all of them considered their penises “short” and in need of reconstruction, none turned out to have a penis that was very short according to established norms or to suffer any other penile abnormality. About 85% of them erroneously expected a normal flaccid penis to measure 3.9 to 6.7 inches (10-17 cm); about 15% could not estimate a normal size. The majority related their misconceptions of penis size to childhood comparisons with their fathers or friends, or to later comparisons with actors in pornographic movies (Mondaini N et al. 2002).

What About All those Magazine and Internet Ads for Penile Augmentation?

Numerous quacks advertise various pills, potions, lotions, stretching devices, and operative procedures to augment the size of any penis, taking advantage of men’s anxieties and desires to become more physically attractive or “sexual superheroes.” Unfortunately, many men fall victim to such charlatans. In general, these methods simply and plainly do not work, despite some claims of penile lengthening of 2—4 cm with some penile extenders used for several hours daily at home but which have not been confirmed by any scientific study reported in peer-reviewed medical journals, and they can cause substantial physical and emotional harm and drain a lot of money from men’s pockets without any clear benefit.

All the stretching methods are of limited efficacy because the dorsal penile nerve cannot be elongated without injury or avulsion (tearing). As mentioned previously, the advertised surgical techniques usually consist of liposuction or lipectomy of the suprapubic fat pad, cutting the sensory ligament that attaches the penis to the pubic bone, or covering the penis with skin flaps from the lower abdomen and then injecting fat to increase its girth. They produce very poor results, generally achieving a wobbling, low-hanging penis that points in any direction except the normal vertical during erection. Scarring and bumps can occur, and clumps of fat can form under the penile skin. Other potential and sometimes devastating complications include infection, ED, shortening, loss of penile sensation, persistent pain, hair growth on the penis, and urinary incontinence.

The American Urological Association, the American Society for Aesthetic Plastic Surgery, and the American Society of Plastic Surgeons have issued policy statements against cosmetic surgical augmentation of a normal-size penis. I want to emphasize as well that bigger is not always better, and that quality is truly much more important than quantity. (I have, in fact, treated several men for ED who were over-endowed with very large genitalia!)

What could cause a Penis to Shrink?

Cold water or cold weather normally shrinks the penis, whereas warm conditions can elongate it. Psychological states such as fear, anger, and anxiety can pull the external genitalia (penis, testicles, and scrotum) closer to the body and may physiologically shorten the penis temporarily.

Are There Men Who Truly do have a Micropenis?

Cases of real micropenis, although rare, merit full evaluation and management. A suggested objective definition of a penis as abnormally short is based on proposed measurements of less than 4.5 cm for flaccid length and less than 7 cm erect or stretched (Wessells H et al. 1996b)—or, more accurately, when stretched flaccid, length is more than two standard deviations below average, according to approved norms.

A thorough medical workup for a man whose penis meets the above definition of small should include karyotyping (chromosomal examination), genetic studies, and evaluation of pituitary and testicular hormones in the bloodstream as well as testosterone and dihydrotestosterone in the genital tissue.

What Are the Most Common Causes of Real Micropenis?

Micropenis is a multifactorial disorder caused by genetic, hormonal, and environmental abnormalities. It can also be associated with ambiguous genitalia or malformations such as hypospadias (an abnormal location of the urethral opening) (Mondaini N, Gontero P 2005).

The essential hormones for penile growth are the androgens (male hormones) testosterone and dihydrotestosterone, as well as luteinizing hormone (LH) from the pituitary gland. In the fetus, proper penile development depends on the conversion of testosterone into dihydrotestosterone by the enzyme 5-alpha reductase in the penis, testicles, scrotum, urethra, and prostate. This development also depends on the presence of intact, functional androgen receptors in the target cells in the internal and external genitalia.

Therefore, any event or abnormality that inhibits androgen production or the action of 5-alpha reductase may lead to male genital underdevelopment. Exposure of a pregnant woman to hormone-disrupting industrial and agricultural chemicals, for example, can interfere with normal sexual differentiation in the fetus. Penile underdevelopment may also result from genetic mutation of the androgen receptors or from any congenital, LH-inhibiting anomaly of the hypothalamus or pituitary gland, as LH normally stimulates the testicles’ Leydig cells to secrete testosterone.

Sometimes, despite normal levels of androgens, the genital tissue is insensitive to them, with the subsequent development of a micropenis that does not respond to testosterone administration. Shortening of the penis may also occur after surgeries such as radical prostatectomy (removal of the prostate and seminal vesicles) to treat prostate cancer or after insertion of penile prostheses to manage ED. And in a few cases, no evident cause for the micropenis is detected, despite a thorough workup.

How is Micropenis Managed or Treated?

In adults, especially in a case of the man’s dissatisfaction with the size of his penis and the ensuing development of severe psychological disturbances, management of the condition depends on the diagnosed causes. Treatment may involve psychiatric counseling; education; liposuction or lipectomy of the excess suprapubic fat; hormone replacement with testosterone or LH; and penile lengthening and/or widening through valid, approved microsurgical techniques performed by a team of expert urologists and plastic surgeons.

In cases of congenital or acquired micropenis—for example, complete or partial penile severance or destruction due to accident, injury, or surgical mishap—several procedures have been effective. With myocutaneous flaps (portions of muscle and skin taken from the upper arm or lower abdomen, with preservation of the nerves), it is possible to add about 2—3 inches to the penile length, or even to create a new penis. A novel procedure using bilateral flaps of the saphenous vein to increase penile girth has also yielded encouraging results (Austoni E et al. 2002).

Even in patients with amputated penises—self-inflicted by mentally disturbed men, or suffered in an accident or at the hands of a jealous or abused wife or mistress—the majority of cases can be treated successfully by microsurgical reattachment, or alternatively, by the creation or reconstruction of a new, functional penis using grafts. More than SO such cases have been reported in the medical literature. I’ve personally performed three successful microsurgical reattachments.

In cases of penile shortening post-prostatectomy, daily use of a vacuum device without the constricting ring may contribute to re-elongation. Other surgical techniques for penile lengthening include the Perovic procedure, which involves penile disassembly, with dissection of the glans penis off the corpora cavernosa and the insertion of a piece of the costal cartilage into the distal corpora (Perovic S et al. 2003); or subcutaneous bulking of the penis with fat, free dermal fat flaps, or biodegradable material. A recent study involving the use of a biodegradable scaffold seeded with fibroblasts configured into a tube and wrapped around the penile shaft yielded good results, with about a 3-centimeter increase in girth (Perovic SV et al. 2006).

What does it Mean When the Penis Bends or Curves During Erection?

Curvature or bending of the penis ventrally (down toward the thighs), laterally (toward either side), or dorsally (back toward the body) during erection, although uncommon, may be very disturbing to the patient. It may be associated with pain, difficulty of penetration, and sometimes ED.

If a bend or curve has been present since birth, it may be due to an abnormal attachment of the penile skin or the subcutaneous fascia (tissues beneath the skin) or to abnormally short corpora cavernosa, both of which can be corrected surgically with excellent results. Ventral bending could very well be congenital, and is most often linked to hypospadias (described previously). In adults, the most common cause of painful penile curvature or bending is a condition called Peyronie’s disease. Ventral bending, in particular, can also be acquired through a fracture of the penis (see the following section) or some other form of trauma to the genitalia.

How Can a Penis be Fractured If It Has No Bone?

Application of the term fracture to the penis may not be fully justified, but it is accepted and used by the medical community for lack of a better description. In most of these unfortunate cases, a man with a full erection, during intercourse or even during sleep, has hit his penis on a solid object or flexed it acutely while rolling in bed. There is usually a crackling sound accompanied by pain, loss of erection, and penile swelling, with a reddish or bluish discoloration; these are due to a rupture of the tunica albuginea, seeping of blood beneath the penile skin, and development of a hematoma (a collection of clotted blood). For most, the ideal treatment is immediate surgical intervention to evacuate the leaked blood and suture the tear in the tunica. Left untreated, a penile fracture may cause scarring at the site of the rupture, with subsequent curvature of the penis during erection.

Author: K. Anthony Hanash. M.D.
Source: New Frontiers in Men’s Sexual Health