Puberty can be considered a continuous process in which the hypothalamic-pituitary-gonadal axis develops from the infantile stages to maturity. The physical development of puberty can be denoted in an objective manner by sexual maturation ratings (SMRs), commonly referred to as Tanner stages. Staging provides an objective, consistent description of physical development, which allows recognition of precocious or delayed puberty or problems with the tempo of pubertal development. In girls, breast development and pubic hair development are usually, but not always coordinated, and should be documented separately. Similarly, in boys, genital development and pubic hair development are typically synchronous but should be described independently.
Findings used for Tanner staging among girls are shown in Figure 533-1A. An increase in growth velocity is one of the first signs of female pubertal onset, but breast development is the first sign noted by most examiners. Breast development among girls can start unilaterally, and asymmetric breast development is not abnormal in early puberty. Breast size and shape are influenced by genetic and nutritional factors, with areolar changes occurring in predictable sequence. The appearance of the vaginal mucosa changes from a prepubertal reddish color to a duller pinkish hue as a result of cornification of the vaginal epithelium, which reflects a change in its histology due to the effect of estrogen. The labia minora and majora thicken, uterine volume and ovarian size increase, and a whitish or clear vaginal discharge occurs prior to menarche. Axillary hair appears and thickens and axillary odor develops as signs of adrenarche, the awakening of adrenal androgen secretion. It is important to note that both boys and girls can achieve fertility before physical maturity is reached.
A: Breast development. Stage B1, prepubertal, elevation of the papilla only. Stage B2, breast buds visible or palpable with enlargement of the areola. Stage B3, further enlargement of the breast and areola with no separation of their contours. Stage B4, projections of areola and papilla to form a secondary mount over the rest of the breast. Stage B5, mature breast with projection of papilla only. Appearance of pubic and labial hair among girls. Stage PH1, prepubertal. Stage PH2, sparse growth of long, straight or slightly curly, minimally pigmented hair, mainly on labia. Stage PH3, considerably darker and coarser hair spreading over mons pubis. Stage PH4, thick adult-type hair that does not yet spread to the medial surface of the thighs. Stage PH5, hair is adult type and is distributed in the classic inverse triangle. B: Genital development and pubic hair growth in boys. Stage G1, prepubertal. Stage G2, enlargement of testis to > 2.5 cm, appearance of scrotal reddening, and increase in rugations. Stage G3, increase in length and to a lesser extent breadth of penis, with further growth of testes and darkening of scrotal skin. Stage G5, adult genitalia. Stage P1, no pubic hair. Stage P2, sparse growth of slightly pigmented, ...