Human penis
In human anatomy, the penis (/ˈpiːnɪs/; pl.: penises or penes; from the Latin pēnis, initially "tail"[1]) is an external male sex organ (intromittent organ) that additionally serves as the urinary duct. The main parts are the root, body, the epithelium of the penis including the shaft skin, and the foreskin covering the glans. The body of the penis is made up of three columns of tissue: two corpora cavernosa on the dorsal side and corpus spongiosum between them on the ventral side. The urethra passes through the prostate gland, where it is joined by the ejaculatory duct, and then through the penis. The urethra goes across the corpus spongiosum and ends at the tip of the glans as the opening, the urinary meatus. It is a passage both for excretion of urine and the ejaculation of semen.
This article is about the human organ. For the organ of male animals in general, see Penis.Human penis
penis, pudendum virile, membrum virile
An erection is the stiffening expansion and orthogonal reorientation of the penis, which occurs during sexual arousal. Erections can occur in non-sexual situations; spontaneous non-sexual erections frequently occur during adolescence and sleep. In its flaccid state, the penis is smaller, gives to pressure, and the glans is covered by the foreskin. In its fully erect state, the shaft becomes rigid and the glans becomes engorged but not rigid. An erect penis may be straight or curved and may point at an upward angle, a downward angle, or straight ahead. As of 2015, the average erect human penis is 13.12 cm (5.17 in) long and has a circumference of 11.66 cm (4.59 in).[2][3] Neither age nor size of the flaccid penis accurately predicts erectile length. There are several common body modifications to the penis, including circumcision and piercings.
The penis is homologous to the clitoris in females.[4]
Potential regeneration
There are efforts by scientists to partially or fully regenerate the structures of the human penis.[75][76][77] Patients who can benefit most from this field are those who have congenital defects, cancer, and injuries that have excised parts of their genitalia.[78][79][80] Some organizations which perform research into, or conduct regeneration procedures, include the Wake Forest Institute for Regenerative Medicine and the United States Department of Defense.[79][80] The first successful penis allotransplant surgery was done in September 2005 in a military hospital in Guangzhou, China.[81] A man at 44 sustained an injury after an accident and his penis was severed; urination became difficult as his urethra was partly blocked. A recently brain-dead man, aged 23, was selected for the transplant. Despite atrophy of blood vessels and nerves, the arteries, veins, nerves and the corpora spongiosa were successfully matched. But, on 19 September (after two weeks), the surgery was reversed because of a severe psychological problem (rejection) by the recipient and his wife.[82]
In 2009, researchers Chen, Eberli, Yoo and Atala have produced bioengineered penises and implanted them on rabbits.[83] They were able to obtain erection and copulate, with 10 of 12 rabbits achieving ejaculation. This study shows that in the future it could be possible to produce artificial penises for replacement surgeries or phalloplasties. In 2015, the world's first successful penis transplant took place in Cape Town, South Africa in a nine-hour operation performed by surgeons from Stellenbosch University and Tygerberg Hospital. The 21-year-old recipient, who had been sexually active, had lost his penis in a botched circumcision at 18.[84]