An orchidometer (or orchiometer) is a

medical instrument A medical device is any device intended to be used for medical purposes. Significant potential for hazards are inherent when using a device for medical purposes and thus medical devices must be proved safe and effective with reasonable assura ...

used to measure the

volume Volume is a measure of occupied 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). Th ...

of the

testicle A testicle or testis (plural testes) is the male reproductive gland or gonad in all bilaterians, including humans. It is homologous to the female ovary. The functions of the testes are to produce both sperm and androgens, primarily testostero ...

s. 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 Andrea is a given name which is common worldwide for both males and females, cognate to Andreas, Andrej and Andrew. Origin of the name The name derives from the Greek word ἀνήρ (''anēr''), genitive ἀνδρός (''andrós''), that re ...

of the

University of Zurich The University of Zürich (UZH, german: Universität Zürich) is a public research university located in the city of Zürich, Switzerland. It is the largest university in Switzerland, with its 28,000 enrolled students. It was founded in 1833 f ...

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

millilitre The litre (international spelling) or liter (American English 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 metre (m3) ...

Doctor Doctor or The Doctor may refer to: Personal titles * Doctor (title), the holder of an accredited academic degree * A medical practitioner, including: ** Physician ** Surgeon ** Dentist ** Veterinary physician ** Optometrist *Other roles ** ...

s sometimes informally refer to them as "Prader's balls", "the medical

worry beads Worry beads or kombolói, kompoloi ( el, κομπολόι, , ''bead collection''; plural: , ) is a string of beads manipulated with one or two hands and used to pass time in Greek and Cypriot culture. Unlike the similar prayer beads used in man ...

", or the "endocrine

rosary The Rosary (; la, , in the sense of "crown of roses" or "garland of roses"), also known as the Dominican Rosary, or simply the Rosary, refers to a set of prayers used primarily in the Catholic Church, and to the physical string of knots or b ...

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 gonads—the testes or the ovaries—that may result in diminished production of sex hormones. Low androgen (e.g., testosterone) levels are referred to as hypoandrogenism and low estrogen ...

. 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. In a minority of childr ...

. 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 hormonal signs that puberty has begun. In the United States, girls ...

. Large testes (

macroorchidism Macroorchidism is a disorder found in males, specifically in children, where a subject has abnormally large testes. The condition is commonly inherited in connection with fragile X syndrome (FXS), which is also the second most common genetic ca ...

) can be a clue to one of the most common causes of inherited generalised learning disability, fragile X syndrome. Stephen Shalet, a leading endocrinologist who works for the

Christie Hospital The Christie Hospital in Manchester, England, is one of the largest cancer treatment centres in Europe. It is managed by The Christie NHS Foundation Trust. History The hospital was established by a committee under the chairmanship of Richard Ch ...

Manchester Manchester () is a city in Greater Manchester, England. It had a population of 552,000 in 2021. It is bordered by the Cheshire Plain to the south, the Pennines to the north and east, and the neighbouring city of Salford to the west. The t ...

, is reported to have told ''

The Observer ''The Observer'' is a British newspaper published on Sundays. It is a sister paper to ''The Guardian'' and ''The Guardian Weekly'', whose parent company Guardian Media Group Limited acquired it in 1993. First published in 1791, it is the w ...

'', "Every endocrinologist should have an orchidometer. It's his stethoscope." Orchidometers are also commonly used to measure testicular volume in

rams In engineering, RAMS (reliability, availability, maintainability and safety)Prader scale The Prader scale or Prader staging, named after Andrea Prader, is a coarse rating system for the measurement of the degree of virilization of the Sex organ, genitalia of the human body and is similar to the Quigley scale. It primarily relates to v ...

Quigley scale The Quigley scale is a descriptive, visual system of phenotypic grading that defines seven classes between "fully masculinized" and "fully feminized" genitalia. It was proposed by pediatric endocrinologist Charmian A. Quigley et al. in 1995. It is ...

. and the satirical

Phall-O-Meter The Phall-O-meter is a satirical measure that critiques medical standards for normal male and female phalluses. The tool was developed by Kiira Triea (Denise Tree) based on a concept by Suzanne Kessler and is used to demonstrate concerns with the ...

See also

References

Further reading