Micropenis Erect With Ruler
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A micropenis or microphallus is an unusually small
penis A penis (; : penises or penes) is a sex organ through which male and hermaphrodite animals expel semen during copulation (zoology), copulation, and through which male placental mammals and marsupials also Urination, urinate. The term ''pen ...
. A common criterion is a dorsal (measured on top) penile length of at least 2.5
standard deviation In statistics, the standard deviation is a measure of the amount of variation of the values of a variable about its Expected value, mean. A low standard Deviation (statistics), deviation indicates that the values tend to be close to the mean ( ...
s smaller than the
mean A mean is a quantity representing the "center" of a collection of numbers and is intermediate to the extreme values of the set of numbers. There are several kinds of means (or "measures of central tendency") in mathematics, especially in statist ...
human penis size Human penis size varies on a number of measures, including length and circumference when flaccid and erect. Besides the natural variability of human penises in general, there are factors that lead to minor variations in a particular male ...
for age. A micropenis is stretched penile length equal to or less than 1.9 cm (0.75 in) in term
infants In common terminology, a baby is the very young offspring of adult human beings, while infant (from the Latin word ''infans'', meaning 'baby' or 'child') is a formal or specialised synonym. The terms may also be used to refer to juveniles of ...
, and 9.3 cm (3.67 in) in adults. The condition is usually recognized shortly after
birth Birth is the act or process of bearing or bringing forth offspring, also referred to in technical contexts as parturition. In mammals, the process is initiated by hormones which cause the muscular walls of the uterus to contract, expelling the f ...
. The term is most often used medically when the rest of the penis,
scrotum In most terrestrial mammals, the scrotum (: scrotums or scrota; possibly from Latin ''scortum'', meaning "hide" or "skin") or scrotal sac is a part of the external male genitalia located at the base of the penis. It consists of a sac of skin ...
, and
perineum The perineum (: perineums or perinea) in placentalia, placental mammals is the space between the anus and the genitals. The human perineum is between the anus and scrotum in the male or between the anus and vulva in the female. The perineum is ...
are without
ambiguity Ambiguity is the type of meaning (linguistics), meaning in which a phrase, statement, or resolution is not explicitly defined, making for several interpretations; others describe it as a concept or statement that has no real reference. A com ...
, such as
hypospadias Hypospadias is a common malformation in fetal development of the penis in which the urethra does not open from its usual location on the head of the penis. It is the second-most common birth defect of the male reproductive system, affecting about ...
. Traditionally, a microphallus describes a micropenis with
hypospadias Hypospadias is a common malformation in fetal development of the penis in which the urethra does not open from its usual location on the head of the penis. It is the second-most common birth defect of the male reproductive system, affecting about ...
. Micropenis incidence is about 1.5 in 10,000 male
newborns In common terminology, a baby is the very young offspring of adult human beings, while infant (from the Latin word ''infans'', meaning 'baby' or 'child') is a formal or specialised synonym. The terms may also be used to refer to juveniles of ...
in
North America North America is a continent in the Northern Hemisphere, Northern and Western Hemisphere, Western hemispheres. North America is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South Ameri ...
.ScienceDaily.com (2004).
Surgeons Pinch More Than An Inch From The Arm To Rebuild A Micropenis
" 6 Dec. 2004, retrieved 2 April 2012.


Causes

Of the abnormal conditions associated with micropenis, most are conditions of reduced prenatal
androgen An androgen (from Greek ''andr-'', the stem of the word meaning ) is any natural or synthetic steroid hormone that regulates the development and maintenance of male characteristics in vertebrates by binding to androgen receptors. This includes ...
production or effect, such as abnormal testicular development (testicular dysgenesis),
Klinefelter syndrome Klinefelter syndrome (KS), also known as 47,XXY, is a chromosome anomaly where a male has an extra X chromosome. These complications commonly include infertility and small, poorly functioning testicles (if present). These symptoms are often n ...
,
Leydig cell hypoplasia Leydig cell hypoplasia (or aplasia) (LCH), also known as Leydig cell agenesis, is a rare autosomal recessive genetic and endocrine syndrome affecting an estimated 1 in 1,000,000 individuals with XY chromosomes. It is characterized by an inability ...
, specific defects of
testosterone Testosterone is the primary male sex hormone and androgen in Male, males. In humans, testosterone plays a key role in the development of Male reproductive system, male reproductive tissues such as testicles and prostate, as well as promoting se ...
or dihydrotestosterone synthesis (
17,20-lyase deficiency Isolated 17,20-lyase deficiency (ILD), also called isolated 17,20-desmolase deficiency, is a rare endocrine and autosomal recessive genetic disorder which is characterized by a complete or partial loss of 17,20-lyase activity and, in turn, impaire ...
, 5α-reductase deficiency),
androgen insensitivity syndrome Androgen insensitivity syndrome (AIS) is a condition involving the inability to respond to androgens, typically due to androgen receptor dysfunction. It affects 1 in 20,000 to 64,000 XY (karyotype, karyotypically male) births. The condition result ...
s, inadequate
pituitary The pituitary gland or hypophysis is an endocrine gland in vertebrates. In humans, the pituitary gland is located at the base of the brain, protruding off the bottom of the hypothalamus. The pituitary gland and the hypothalamus control much of th ...
stimulation (
gonadotropin Gonadotropins are glycoprotein hormones secreted by gonadotropic cells of the anterior pituitary of vertebrates. They are central to the complex endocrine system that regulates normal growth, sexual development, and reproductive function. T ...
deficiency), and other forms of congenital
hypogonadism Hypogonadism means diminished functional activity of the human gonad, gonads—the testicles or the ovary, ovaries—that may result in diminished biosynthesis, production of sex hormones. Low androgen (e.g., testosterone) levels are referred t ...
. Micropenis can also occur as part of many genetic malformation syndromes that do not involve the sex chromosomes. It is sometimes a sign of congenital
growth hormone deficiency Growth hormone deficiency (GHD), or hyposomatotropism, is a medical condition resulting from not enough growth hormone (GH). Generally the most noticeable symptom is that an individual attains a short height. Newborns may also present low blood ...
or congenital
hypopituitarism Hypopituitarism is the decreased (''hypo'') secretion of one or more of the eight hormones normally produced by the pituitary gland at the base of the brain. If there is decreased secretion of one specific pituitary hormone, the condition is know ...
. Several
homeobox A homeobox is a Nucleic acid sequence, DNA sequence, around 180 base pairs long, that regulates large-scale anatomical features in the early stages of embryonic development. Mutations in a homeobox may change large-scale anatomical features of ...
genes affect penis and digit size without detectable hormone abnormalities. In addition,
in utero The uterus (from Latin ''uterus'', : uteri or uteruses) or womb () is the organ in the reproductive system of most female mammals, including humans, that accommodates the embryonic and fetal development of one or more fertilized eggs until bir ...
exposure to some estrogen-based fertility drugs like
diethylstilbestrol Diethylstilbestrol (DES), also known as stilbestrol or stilboestrol, is a nonsteroidal estrogen medication, which is presently rarely used. In the past, it was widely used for a variety of indications, including pregnancy support for those with ...
(DES) has been linked to genital abnormalities or a smaller than normal penis. After evaluation to detect any of the conditions described above, micropenis can often be treated in infancy with injections of various
hormone A hormone (from the Ancient Greek, Greek participle , "setting in motion") is a class of cell signaling, signaling molecules in multicellular organisms that are sent to distant organs or tissues by complex biological processes to regulate physio ...
s, such as
human chorionic gonadotropin Human chorionic gonadotropin (hCG) is a hormone for the maternal recognition of pregnancy produced by trophoblast cells that are surrounding a growing embryo (syncytiotrophoblast initially), which eventually forms the placenta after implantat ...
and
testosterone Testosterone is the primary male sex hormone and androgen in Male, males. In humans, testosterone plays a key role in the development of Male reproductive system, male reproductive tissues such as testicles and prostate, as well as promoting se ...
.


Treatment


Hormone treatment

Growth of the penis both before birth and during childhood and puberty is strongly influenced by
testosterone Testosterone is the primary male sex hormone and androgen in Male, males. In humans, testosterone plays a key role in the development of Male reproductive system, male reproductive tissues such as testicles and prostate, as well as promoting se ...
and, to a lesser degree, the
growth hormone Growth hormone (GH) or somatotropin, also known as human growth hormone (hGH or HGH) in its human form, is a peptide hormone that stimulates growth, cell reproduction, and cell regeneration in humans and other animals. It is thus important in ...
. However, later endogenous hormones mainly have value in the treatment of micropenis caused by hormone deficiencies, such as
hypopituitarism Hypopituitarism is the decreased (''hypo'') secretion of one or more of the eight hormones normally produced by the pituitary gland at the base of the brain. If there is decreased secretion of one specific pituitary hormone, the condition is know ...
or
hypogonadism Hypogonadism means diminished functional activity of the human gonad, gonads—the testicles or the ovary, ovaries—that may result in diminished biosynthesis, production of sex hormones. Low androgen (e.g., testosterone) levels are referred t ...
. Regardless of the cause of micropenis, if it is recognized in infancy, a brief course of testosterone is often prescribed (usually no more than three months). This usually induces a small amount of growth, confirming the likelihood of further growth at puberty, but rarely achieves normal size. No additional testosterone is given during childhood, to avoid unwanted
virilization Virilization or masculinization is the biological development of adult male characteristics in young males or females. Most of the changes of virilization are produced by androgens. Virilization is a medical term commonly used in three medical a ...
and
bone maturation Bone age is the degree of a person's skeletal development. In children, bone age serves as a measure of physiological maturity and aids in the diagnosis of growth abnormalities, endocrine disorders, and other medical conditions. As a person grows ...
. There is also some evidence that premature administration of testosterone can lead to reduced penis size in the adult. Testosterone treatment is resumed in adolescence only for boys with hypogonadism. Penile growth is completed at the end of puberty, similar to the completion of height growth, and provision of extra testosterone to post-pubertal adults produces little or no further growth.


Surgery

Because hormone treatment rarely achieves average size, several surgical techniques similar to
phalloplasty Phalloplasty (also called penoplasty) is the construction or reconstruction of a penis or the artificial modification of the penis by surgery. The term is also occasionally used to refer to penis enlargement. History Russian surgeon Nikolaj B ...
for
penis enlargement Penis enlargement, or male enhancement, is any technique aimed to increase the size of a human penis. Some methods aim to increase total length, others the shaft's girth, and yet others the glans and foreskin size. Techniques include surgery, ...
have been devised and performed, but they are not generally considered successful enough to be widely adopted and are rarely performed in childhood. In extreme cases of micropenis, there is barely any shaft, and the glans appears to sit almost on the pubic skin. From the 1960s until the late 1970s, it was common for sex reassignment and
surgery Surgery is a medical specialty that uses manual and instrumental techniques to diagnose or treat pathological conditions (e.g., trauma, disease, injury, malignancy), to alter bodily functions (e.g., malabsorption created by bariatric surgery s ...
to be recommended. This was especially likely if evidence suggested that response to additional testosterone and pubertal testosterone would be poor. With parental acceptance, the boy would be reassigned and renamed as a girl, and surgery performed to remove the testes and construct an artificial vagina (
vaginoplasty Vaginoplasty is any surgical procedure that results in the construction or reconstruction of the vagina. It is a type of genitoplasty. Pelvic organ prolapse is often treated with one or more surgeries to repair the vagina. Sometimes a vaginoplas ...
). This was based on the now-questioned idea that gender identity was shaped entirely from socialization, and that a man with a small penis can find no acceptable place in society.
Johns Hopkins Hospital Johns Hopkins Hospital (JHH) is the teaching hospital and biomedical research facility of Johns Hopkins School of Medicine in Baltimore, Maryland. Founded in 1889, Johns Hopkins Hospital and its school of medicine are considered to be the foundin ...
, the center most known for this approach, performed twelve such reassignments from 1960 to 1980, most notably that of
David Reimer David Reimer (born Bruce Peter Reimer; 22 August 1965 – 4 May 2004) was a Canadian man raised as a girl following medical advice and intervention after his penis was severely injured during a botched circumcision in infancy. The psychologis ...
(whose penis was destroyed by a circumcision accident), overseen by
John Money John William Money (8 July 1921 – 7 July 2006) was a New Zealand American psychologist, sexologist and professor at Johns Hopkins University known for his research on human sexual behavior and gender. Money advanced the use of more accur ...
. By the mid-1990s, reassignment was less often offered, and all three premises had been challenged. Former subjects of such surgery, vocal about their dissatisfaction with the adult outcome, played a large part in discouraging this practice. Sexual reassignment is rarely performed today for severe micropenis (although the question of raising the boy as a girl is sometimes still discussed).


See also

*
Buried penis Buried penis, also called hidden penis or retractile penis, is a Birth defect, congenital or acquired condition in which the human penis, penis is partially or completely hidden below the surface of the skin. A buried penis can lead to urinary d ...
*
Clitoromegaly Clitoromegaly (or macroclitoris) is an abnormal enlargement of the clitoris that is mostly congenital; it is otherwise acquired through deliberately induced clitoral enlargement, a form of body modification, by use of anabolic steroids, in parti ...
*
Hard flaccid syndrome Hard flaccid syndrome (HFS), also known as hard flaccid (HF), is a rare acquired dysautonomic condition characterized by a flaccid penis that remains in a firm, semi-rigid state in the absence of sexual arousal. Patients often describe their flac ...
*
Intersex Intersex people are those born with any of several sex characteristics, including chromosome patterns, gonads, or genitals that, according to the Office of the United Nations High Commissioner for Human Rights, "do not fit typical binar ...
* Penis size *
Webbed penis Webbed penis also known as buried or concealed penis is an acquired or congenital condition in which the scrotal skin extends onto the ventral penile shaft. The penile shaft is buried in the scrotum or tethered to the scrotal midline by a fold or w ...


References


External links


Into the Hands of Babes
by Melissa Hendricks, '' Johns Hopkins Magazine''
"Effect of penile size on nocturnal erections: evaluation with NPTR testing with men having micropenis"
from the ''
International Journal of Impotence Research ''IJIR: Your Sexual Medicine Journal'' is a bimonthly peer-reviewed medical journal covering the study of sexual dysfunction. It was established in 1989 and is published by Springer Nature. The editor-in-chief is Ege Can Serefoglu. According to th ...
'' {{Male congenital malformations of genital organs, indeterminate sex and pseudohermaphroditism Congenital disorders of male genital organs Intersex variations Penis disorders