Page 681 - First Aid for the USMLE Step 1 2020, Thirtieth edition [MedicalBooksVN.com]_Neat
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RepRoductive ` REPRODUCTIVE—PHySIOlOgy RepRoductive ` REPRODUCTIVE—PHySIOlOgy SectioN iii 637
Tanner stages of sexual development
Tanner stage is assigned independently to genitalia, pubic hair, and breast (eg, a person can
have Tanner stage 2 genitalia, Tanner stage 3 pubic hair). Earliest detectable secondary sexual
characteristic is breast bud development in girls, testicular enlargement in boys.
Stage I Stage II Stage III Stage IV Stage V
No sexual hair Pubic hair appears Coarsening of pubic Coarse hair across pubis, Coarse hair across pubis and
Flat-appearing chest with (pubarche) hair sparing thigh medial thigh
raised nipple Testicular enlargement Penis size/length Penis width/glans Penis and testis enlarge to
Breast bud forms Breast enlarges Breast enlarges, raised adult size
(thelarche), mound forms areola, mound on mound Adult breast contour, areola
flattens
Pre-pubertal ~ 8 11.5 years ~ 11.5–13 years ~ 13–15 years Usually > 15 years
Precocious puberty Appearance of 2° sexual characteristics (eg, adrenarche, thelarche, menarche) before age 8 years in
girls and 9 years in boys. sex hormone exposure or production linear growth, somatic and
skeletal maturation (eg, premature closure of epiphyseal plates short stature). Types include:
Central precocious puberty ( GnRH secretion): idiopathic (most common; early activation of
hypothalamic-pituitary gonadal axis), CNS tumors.
Peripheral precocious puberty (GnRH-independent; sex hormone production or exposure
to exogenous sex steroids): congenital adrenal hyperplasia, estrogen-secreting ovarian tumor
(eg, granulosa cell tumor), Leydig cell tumor, McCune-Albright syndrome.
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