Tanner Stages

The Tanner Stages, also known as the Tanner Scale, are a method of describing the physical development of human beings from their time as children through adolescence and to adulthood. This is based on an examination of external primary and secondary sex characteristics, and is important to measure puberty and other developments, as well as work out what form of medication to prescribe for some treatments such as for human immunodeficiency virus (HIV), as puberty may occur at different ages in different people.

The concept of the Tanner Stages was developed by James Mourilyan Tanner who was born near London, United Kingdom, and studied at Queen Mary's Hospital, University of London, the Medical School at the University of Pennsylvania, and at the Medical School at Johns Hopkins University, becoming a Reader in Growth and Development at the Institute of Child Health at the University of London, a position he held from 1956, and was the author of a large number of scholarly papers, and also two books, on the field.

There are five stages in the Tanner Scale, with the first having both males and females having no pubic hair, males having a small testicular volume, and females having no glandular tissue, with the areola following the skin contours of the chest. In Stage II, males and females have a small amount of long downy hair, with males having a testicular volume between 1.6 milliliter and 6 milliliter, and females having breast [Page 1644]buds forming with a small area of surrounding glandular tissue and the areola starting to widen.

In Stage III, the pubic hair becomes coarse and curly, and begins to extend laterally, with males having a testicular volume of between 6 and 12 milliliter and a larger scrotum than before, and females having more elevated breasts that extend beyond the borders of the areola. Stage IV has significant pubic hair for males and females, testicular volume between 12 and 20 milliliter, with a larger and darker scrotum, and enlarged penile dimensions, and females having much larger and more elevated breasts, and the areola and papilla forming a secondary mound which projects out from the contour of the breasts. Stage V is full adulthood with pubic hair spreading across the thighs, males having a testicular volume greater than 20 milliliter, and females having full adult-size breasts.