An orchidometer (or orchiometer) is a medical instrument used to measure the

volume Volume is a measure of regions in three-dimensional space. It is often quantified numerically using SI derived units (such as the cubic metre and litre) or by various imperial or US customary units (such as the gallon, quart, cubic inch) ...

of the

testicle A testicle or testis ( testes) is the gonad in all male bilaterians, including humans, and is Homology (biology), homologous to the ovary in females. Its primary functions are the production of sperm and the secretion of Androgen, androgens, p ...

Instrument

The orchidometer was introduced in 1966 by Swiss pediatric

endocrinologist Endocrinology (from ''endocrine'' + '' -ology'') is a branch of biology and medicine dealing with the endocrine system, its diseases, and its specific secretions known as hormones. It is also concerned with the integration of developmental events ...

Andrea Prader of the

University of Zurich The University of Zurich (UZH, ) is a public university, public research university in Zurich, Switzerland. It is the largest university in Switzerland, with its 28,000 enrolled students. It was founded in 1833 from the existing colleges of the ...

. Page 16in: It consists of a string of twelve numbered wooden or plastic beads of increasing size from about 1 to 25

millilitre The litre ( Commonwealth spelling) or liter ( American spelling) (SI symbols L and l, other symbol used: ℓ) is a metric unit of volume. It is equal to 1 cubic decimetre (dm3), 1000 cubic centimetres (cm3) or 0.001 cubic metres (m3). A cu ...

Doctor Doctor, Doctors, The Doctor or The Doctors may refer to: Titles and occupations * Physician, a medical practitioner * Doctor (title), an academic title for the holder of a doctoral-level degree ** Doctorate ** List of doctoral degrees awarded b ...

s sometimes informally refer to them as "Prader's balls", "the medical worry beads", or the "endocrine

rosary The Rosary (; , in the sense of "crown of roses" or "garland of roses"), formally known as the Psalter of Jesus and Mary (Latin: Psalterium Jesu et Mariae), also known as the Dominican Rosary (as distinct from other forms of rosary such as the ...

". Page 86in: The beads are compared with the testicles of the patient, and the volume is read off the bead which matches most closely in size. Prepubertal sizes are 1–3 ml, pubertal sizes are considered 4 ml and up and adult sizes are 15-25 ml. The orchidometer can be used to accurately determine size of testes. Discrepancy of testicular size with other parameters of maturation can be an important clue to various diseases. Small testes can indicate either primary or secondary

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 ...

. Testicular size can help distinguish between different types of

precocious puberty In medicine, precocious puberty is puberty occurring at an unusually early age. In most cases, the process is normal in every aspect except the unusually early age and simply represents a variation of normal development. There is early developm ...

. Since testicular growth is typically the first physical sign of true puberty, one of the most common uses is as confirmation that puberty is beginning in a boy with

delayed puberty Delayed puberty is when a person lacks or has incomplete development of specific sexual characteristics past the usual age of onset of puberty. The person may have no physical or hormone, hormonal signs that puberty has begun. In the United States ...

. Large testes (

macroorchidism Macroorchidism is a Genetic disorder, disorder found in males, specifically in children, where a subject has abnormally large testes. The Medical condition, condition is commonly genetics, inherited in connection with fragile X syndrome, fragile X ...

) can be a clue to one of the most common causes of inherited generalised learning disability,

fragile X syndrome Fragile X syndrome (FXS) is a genetic neurodevelopmental disorder. The average IQ in males with FXS is under 55, while affected females tend to be in the borderline to normal range, typically around 70–85. Physical features may include a lo ...

. Stephen Shalet, a leading endocrinologist who works for the

Christie Hospital The Christie, formerly known as Christie Hospital and The Christie Hospital and Holt Radium Institute, is a specialist National Health Service, National Health Service (NHS) single site cancer centre in Manchester, United Kingdom. The hospital is ...

Manchester Manchester () is a city and the metropolitan borough of Greater Manchester, England. It had an estimated population of in . Greater Manchester is the third-most populous metropolitan area in the United Kingdom, with a population of 2.92&nbs ...

, is reported to have told ''

The Observer ''The Observer'' is a British newspaper published on Sundays. First published in 1791, it is the world's oldest Sunday newspaper. In 1993 it was acquired by Guardian Media Group Limited, and operated as a sister paper to ''The Guardian'' ...

'': "Every endocrinologist should have an orchidometer. It's his

stethoscope The stethoscope is a medicine, medical device for auscultation, or listening to internal sounds of an animal or human body. It typically has a small disc-shaped resonator that is placed against the skin, with either one or two tubes connected t ...

." Orchidometers are also commonly used to measure testicular volume of

rams In engineering, reliability, availability, maintainability and safety (RAMS)Prader scale, Quigley scale, and the satirical Phall-O-Meter.

Instrument

References

Further reading