Pubertal Development: the Human Metamorphosis

Objectives

• Describe the process by which children undergo sexual maturation
• Highlight the method of Tanner staging used by health care professionals
• Describe gender-specific changes that occur during puberty
• List the common pubertal disorders health care providers will encounter

Puberty

• Hypothalamic stimulation (GnRH) of pituitary gonadotropins (LH/FSH) leading to gonadal sex steroid production (estrogen/testosterone)
• Sexual maturation (secondary sexual characteristics)
• Acceleration (and eventual completion) of somatic growth
• Capacity for reproduction(menstruation/spermatogenesis)

Onset
Females:
Initial changes 11 yrs mean (8-14 yrs range)
Breast - pubic hair - menses - axillary hair

Males:
Initial changes 11.5 yrs mean (9-13 yrs range)
Testicular volume - pubic hair - axillary hair - voice change - facial hair

Duration
Average duration 3-4 years from onset to completion of pubertal changes

Tanner Staging
James Mourilyan Tanner (1920 -2010)
British pediatric endocrinologist
Charted & photographed growth of children over period of years
Scale measures sexual maturation in adolescents based on measureable indicators:

• size of the genitals
• quantity of pubic hair

Pubic Hair Development

• Tanner I  no pubic hair at all (prepubertal) [typically age 10 and younger]
• Tanner II  small amount of long, downy hair with slight pigmentation at the base of the penis and scrotum (males) or on the labia majora (females) [10–11.5yr]
• Tanner III  hair becomes more coarse and curly, and begins to extend laterally [11.5–13yr]
• Tanner IV  adult-like hair quality, extending across pubis but sparing medial thighs [13–15yr]
• Tanner V  hair extends to medial surface of the thighs [15+yr]

Female Development

• Tanner I  no glandular tissue: areola follows the skin contours of the chest (prepubertal) [typically age 10 and younger]
• Tanner II  breast bud forms, with small area of surrounding glandular tissue; areola begins to widen [10-11.5yr]
• Tanner III  breast begins to become more elevated, and extends beyond the borders of the areola, which continues to widen but remains in contour with surrounding breast [11.5-13yr]
• Tanner IV  increased breast size and elevation; areola and papilla form a secondary mound projecting from the contour of the surrounding breast [13-15yr]
• Tanner V  breast reaches final adult size; areola returns to contour of the surrounding breast, with a projecting central papilla [15+ yr).

Male Development

• Tanner I  prepubertal (testicular volume less than 1.5 ml; small penis of 3 cm or less) [typically age 9 and younger]
• Tanner II  testicular volume between 1.6 and 6 ml; skin on scrotum thins, reddens and enlarges; penis length unchanged [9-11 yr]
• Tanner III  testicular volume between 6 and 12 ml; scrotum enlarges further; penis begins to lengthen to about 6 cm [11-12.5 yr]
• Tanner IV  testicular volume between 12 and 20 ml; scrotum enlarges further and darkens; penis increases in length to 10 cm and circumference [12.5-14 yr]
• Tanner V  testicular volume greater than 20 ml; adult scrotum and penis of 15 cm in length [14+ yr]

Pubertal Disorders

Female

• Precocious/delayed puberty
• Virilizing conditions (tumors, PCOS, CAH)

Male

• Precocious/delayed puberty
• Feminizing conditions (tumors, gynecomastia)

Conclusions

• Dynamic process
• Usually 3-4 yr window
• Identifying normal development will aid in intervening with abnormal development