Male Sexual Maturity Rating
Information has been excerpted from VisualDx clinical decision support system as a public health service. Additional information, including symptoms, diagnostic pearls, differential diagnosis, best tests, and management pearls, is available in VisualDx.
Synopsis
Tanner staging, also known as sexual maturity rating, is a uniformly accepted scale to describe the onset and progression of pubertal changes. Boys are rated on a 1-5 scale based upon their genital development and pubic hair growth. In males, onset of puberty ranges from ages 9 to 14 years.
Genital staging as well as other physical markers of puberty (eg, height velocity) are more reliable than pubic hair staging for assessing pubertal development since the adrenal axis matures independently.
Look For
Male external genitalia scale:
- Stage I – Testicular volume < 4 ml or long axis < 2.5 cm. The penis, testes, and scrotal sac are of a size seen in childhood.
- Stage II – Testicular volume 4-8 ml (or 2.5-3.3 cm long). Gonadarche is the first pubertal sign. There is enlargement of the scrotal sac and testes with a change in the texture of the scrotal skin (development of ridges, or rugae) as well as some reddening.
- Stage III – Testicular volume 9-12 ml (or 3.4-4.0 cm long). There is increase in length and circumference of the penis as well as further growth of the testes and scrotal sac. During stage III, males typically undergo peak height velocity.
- Stage IV – Testicular volume 15-20 ml (or 4.1-4.5 cm long). The penis continues to grow in length and circumference with further development of the glans penis. There is further growth of the testes and scrotal sac with darkening of the scrotal skin. Spermarche typically occurs at this stage.
- Stage V – Testicular volume > 20 ml (or >4.5 cm long). Adult genitalia in size and shape.
Pubic hair scale:
- Stage I – No sexual hair. Vellus hair appears similar to that over the abdominal wall.
- Stage II – Downy hair. There is a sparse distribution of long, dark, downy hair that is straight or slightly wavy, found at the base of the penis.
- Stage III – Scant terminal hair. The hair is significantly darker, courser, and curlier. The hair has spread over the junction of the pubis.
- Stage IV – Terminal hair that fills the entire triangle overlying the pubic region. The hair is as course as adult hair, but the distribution is less than that seen in an adult male.
- Stage V – Terminal hair that extends beyond the inguinal crease onto the thigh. The hair is of adult distribution and type. The area of coverage appears as an inverse triangle with spread to the medial surface of the thighs.
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