Sexual Maturity Rating – SMR in boys and girls

In girls, the 1st visible sign of puberty and the hallmark of SMR 2 is the appearance of breast buds, between 8 and 12 yr of age. Menses typically begins 2-2.5 yr later, during SMR3-4 (median age, 12 yr; normal range, 9-16 yr). Less obvious changes include enlargement of the ovaries, uterus, labia, and clitoris, and thickening of the endometrium and vaginal mucosa.

In boys, the 1st visible sign of puberty and the hallmark of SMR2 is testicular enlargement, beginning as early as 9.5 yr. This is followed by penile growth during SMR3. Peak growth occurs when testis volumes reach approximately 9-10 cm3 during SMR4. Under the influence of LH and testosterone, the seminiferous tubules, epididymis, seminal vesicles, and prostate enlarge. The left testis normally is lower than the right. Some degree of breast hypertrophy, typically bilateral, occurs in 40-65% of boys during SMR2-3 due to a relative excess of estrogenic stimulation.

SMR in girls and boys SMR in girls and boys
Growth acceleration begins in early adolescence for both sexes, but peak growth velocities are not reached until SMR3-4. Boys typically peak 2-3 yr later than girls, begin this growth at a later SMR stage (Fig. 104-5), and continue their linear growth for approximately 2-3 yr after girls have stopped.
CLASSIFICATION OF SEXUAL MATURITY STATES IN GIRLS
SMR STAGE PUBIC HAIR BREASTS
1 Preadolescent Preadolescent
2 Sparse, lightly pigmented, straight, medial border of labia Breast and papilla elevated as small mound; diameter of areola increased
3 Darker, beginning to curl, increased amount Breast and areola enlarged, no contour separation
4 Coarse, curly, abundant, but less than in adult Areola and papilla form secondary mound
5 Adult feminine triangle, spread to medial surface of thighs Mature, nipple projects, areola part of general breast contour

 

CLASSIFICATION OF SEX MATURITY STATES IN BOYS
SMR STAGE PUBIC HAIR PENIS TESTES
1 None Preadolescent Preadolescent
2 Scanty, long, slightly pigmented Minimal change/enlargement Enlarged scrotum, pink, texture altered
3 Darker, starting to curl, small amount Lengthens Larger
4 Resembles adult type, but less quantity; coarse, curly Larger; glans and breadth increase in size Larger, scrotum dark
5 Adult distribution, spread to medial surface of thighs Adult size Adult size

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