About the penis: its size, anatomy, and how to keep it healthy and performing to the fullest
- It has more nicknames than any other body part, and some think it has its own brain
- The penis carries out two basic but important functions, and its condition is a bellwether of a man’s health and risk of disease
The male sex organ is frequently discussed by both men and women – whether with bravado, in embarrassment, competitively or amid hushed giggles.
Referred to in myriad ways, from conservative terms such as phallus, member, or family jewels, to myriad slang terms – among them knob, willy or pecker – the penis has inspired wonder, desire and mirth. It is referenced in mythology, and today mystery still surrounds it.
The size and shape of a man’s penis is a point of scrutiny and discussion. According to the UK’s National Health Service, the average penis is about 9cm (3.75 inches) long when not erect, and from 13cm to 18cm (5in to 7in) when erect.
Humans have larger penises than all other primates, but theirs in turn are dwarfed by that of the blue whale, which is 2.4 metres (7.87 feet) long.
Men’s ancestors had “spines” on their penises – small barbs of hard tissue formed of keratin which lined the outside of the organ. Some animals, such as chimpanzees and domestic cats, still have them, and they aid in the competition to fertilise females.
The organ has two primary functions: disposing of waste (urine) and transferring semen. It reaches its full size during puberty, and has several parts: the glans (or head) which is covered by the foreskin, corpus cavernosum (two columns of tissue along the sides of the penis that fill with blood to cause an erection), corpus spongiosum (a body of tissue which runs from the body to the top of the penis) and the urethra (the pipeline for semen and urine).