Puberty is a period of biological maturation marked by the appearance
of secondary sexual characteristics, growth spurt, and changes in
body composition. With the exception of the fetal period, there
is no other stage in human development in which height growth and
changes in body composition are as intense and rapid as during puberty.
The growth spurt, for example, lasts three to four years and represents
approximately a 20% and 50% gain in relation to adult height and
In adolescence, chronological age is not a reliable parameter for
biological, psychological, and social characterization of individuals.
Adolescents with the same age are frequently in different stages
of puberty considering that its onset and progression are highly
variable. Most pubertal events (maximum growth velocity, menarche,
final height, and so on) and most pathologies associated to puberty
(acne, scoliosis, gynecomasty, and so on) are more often correlated
to specific stages of puberty than to chronological age(
Pubertal staging allows doctors to assess the maturation of adolescent
patients; to correlate several pubertal phenomena; to estimate age
at menarche, growth spurt, and final height; to offer early orientation
to youngsters in relation to upcoming pubertal events; to offer
advice on choice of proper sports modalities; to assess exams properly;
and to treat pathologies associated to puberty( ).
In this sense, pubertal staging is an important measure for characterizing
the maturation of adolescents and for easier understanding and handling
of the most common clinical problems for this age group. Our objective
is to offer a brief review on the practice of pubertal staging,
and to present a new photographic model on the stages of sexual
maturation and a new method for measurement of testicular volume.
Though certain models of pubertal staging had already been proposed
during the 1940s and 1950s(
doctor J.M. Tanner was the one who presented a standardized method
for staging of sexual maturation( ),
which became widely used during the 1960s and is still the most
widely used method.
Staging of sexual maturation is carried out with breast and pubic
hair growth examination for girls, and with genital and pubic hair
growth for boys. Breasts and genitals are examined according to
size, shape, and characteristics and pubic hair according to quantity
and distribution (Table 1). Stage 1 (Tanner 1) corresponds to the
prepubertal phase and stage 5 (Tanner 5) corresponds to late-pubertal
(adult) phase. In this sense, stages 2, 3, and 4, or the midpubertal
stages, represent puberty. Stages 2 to 4 are conventionally called
sexual maturation stages, or Tanner stages.
Table 1 -
Sexual maturity rating
The classical work of Tanner included a set of black-and-white
photographs for illustration of each maturation stage for both sexes(
A few years later, a Dutch group published a set of color photographs
for these same stages( ).
In this article, we reproduce our black-and-white model for sexual
maturation (Figures 1, 2, 3, and 4) originally published in 1995( ).
This is the first published Brazilian model and the third in the
Figure 1 - Stages of sexual maturation in males - genitals
Figure 2 - Stages of sexual maturation in males - pubic hair
Figure 3 - Stages of sexual maturation in females - breasts
Figure 4 - Stages of sexual maturation in females - pubic hair
For each sex, staging is carried out according to two steps: breasts
(B) and pubic hair (P) growth for girls, and genitals (G) and pubic
hair (P) for boys (Table 1). It is recommended to always assess
these two steps separately; for example, B3P3 instead of stage 3.
Adolescents may be in different maturation stages for each of the
two characteristics, for example, B4P5 or G2P1 considering that
maturation of the characteristics depends on different hormonal
and genetic mechanisms. Pubertal events correlate differently to
specific components of maturation staging; for example, age at menarche
is more correlated to breast development than to pubic hair growth.
Most adolescents do not present differences of more than one stage
between B and G in relation to P; however, situations of G1P3, G4P1,
or M3P1, though rare, can be observed in normal adolescents. Nevertheless,
important differences as such can also be an indication of a pathology
(supra-renal, testicular, etc)(
During puberty, there is an increment in nipple (papilla) and nipple
areola in both girls and boys, but especially in the earlier. The
increment in nipple diameter is greater during stages B4 and B5,
which helps to differentiate stages B3, B4, and B5. The nipple presents
little increase between stages 1 and 3 and marked increase between
stages B3 and B4 (diameter averages of 3 mm for B1; 3.4 mm for B2;
4.7 mm for B3; 7.3 mm for B4; and 9.4 mm for B5)(
Initially, the appearance of thelarche (B2) may occur in only one
breast; the contralateral breast will usually start growing weeks
or months later. Breast asymmetries, however, can persist for some
time between B2 and B4 or, in some women, be permanent. The stage
B4 is not observed in all girls; apparently, some female individuals
go directly from B3 to B5 or stage B4 occurs so rapidly that it
is not registered in successive medical appointments. Conversely,
in other girls breast development may stop in stage B4.
The stage 6 of pubic hair growth is observed in approximately 80%
of men and 10% of women; in certain individuals, it will only be
complete years after puberty is over.
The measurement of testicular volume represents an additional instrument
for assessment of male sexual maturation.
The most widely used method for measuring testicular volume uses
the Prader orchidometer, which includes 12 ellipsoid testicular
models made of wood or plastic and attached to a string. The models
have volumes of one to 25 ml(
To assess testicular volume, the doctor palpates the testis with
one hand while holding the orchidometer in the other, examining
the patient for the model that is more similar to the palpated testis.
Takihara et al.(
proposed a new orchidometer that consists of a graded series of
punched-out elliptical rings with the volume of the ellipsoids indicated
on each ring for volumes of 1 to 30 ml.
Considering that orchidometers are not easily available in our
setting, other methods that offer similar precision can be applied.
Thus, it is also possible to measure the two axes of the testis
with a transparent ruler or, better yet, with a caliper (similar
to that used for measurement of skinfold) and calculate the volume
using the formula V = 0.523 x L x C(
with V for volume, L for longitudinal diameter, and C for cross-sectional
The measurement of testicular volume by ultrasonography employs
the same principle, though it has been reported as the most precise
We were able to show, in a different article, that all methods offer
comparable reliability as long as the volumes obtained are corrected
using the equations of the linear structural model( ).
In this sense, it was possible to propose a method for visual comparison
of the palpated testes with graphic models for estimation of testicular
volume (Figure 5); this new proposed method is, thus, simple and
its reliability comparable to that of orchidometer and ultrasonography( ).
Figure 5 - Scheme for graphic measurement of testicular volume. The
testicle is palpated and visually compared with the graphic models.
Testicular volume is determined according to one of the six volumes
or one of the intermediate volumes between two consecutive volumes
depicted . The entire measurement scale includes 13 volumes: less
than 2ml, 2ml, 3.5ml, 5ml, 7.5ml, 10ml, 12.5ml, 15ml, 17.5ml, 20ml,
22.5ml, 25ml, and greater than 25ml
In general, the testes of children have one to two, and sometimes
three, ml in volume. Testes with four ml or more are, almost as
a rule, characteristic of puberty. Consequently, attaining a volume
of four ml or more is an indication of G2; this is an example of
how measurement of testicular volume can help to carry out pubertal
staging. A testicular volume of three ml is generally prognostic
of puberty, for an estimated 80% chance of starting within the following
Eleven to 12-year old boys with small testes (one to two ml) are
probably affected by delay of pubertal development (usually constitutional).
Measuring testicular volume is also important for the assessment
of diagnosis of certain pathologies; for example, cases of Klinefelter
syndrome (small testes) or of Fragile-X syndrome (possible macro-orchidism).
The follow-up measurement of testicular volume is important in postsurgical
follow-up of orchipexy (to check whether ectopy, twisting and/or
surgical handling has affected testicular development) or of varicocele
(that presents risk for testicular hypertrophy and subfertility).
Most adolescents have similar left- and right-hand side testicular
volumes; however, it is common for the left-hand side testicle to
have a slightly lower volume than the right-hand side one. In cases
of significant differences (20%), it is important to examine the
patient for factors that may be interfering in growth of the smaller
testis (varicocele, previous surgery, orchitis, twisting, etc).
Testicular volume is significantly correlated with the testicular
function. Some authors consider a testicular volume of 12 ml, attained,
in average, around 13 to 14 years of age and during maximum growth
velocity, the minimum volume compatible with fertility; in this
sense, attainment of this volume is comparable to menarche as a
reference for male sexual maturity(
The average testicular volume of Brazilian adolescents is four
ml for G2, nine ml for G3, 16 ml for G4, and 20 ml for G5. However,
there can be significant variations in these values. Consequently,
a specific testicular volume cannot be used to define stage of sexual
maturation. Adult testes, for example, can vary from 12 to 30 ml