Learn how to determine skeltal age from physical examination and x rays.
Transcript of this audio tutorial
Measurement of skeletal age
You as a medical practitioner will often be asked to determine a patients
bone age. The reason may be legal. Many countries punish a criminal act
perpetrated by minor, often defined as under 18, less severely than his
older peer. Fractures are often treated differently in the immature skeleton
and when growth ceases also has an effect on spinal deformities such as
How do we determine how skeletally mature a child is?
There are many aspects to maturation. This includes the development of
reproductive and secondary sexual characteristics, changes in muscle and
fat mass and distribution, as well as changes in bone structure.
The age at which the growth spurt occurs varies greatly. Normal puberty
has a 4 year variation in the age at which it takes place. Humans have
two basic pubertal stages, consisting of adrenarche and gonadarche. Adrenache
is when the adrenal cortex mature (at about 6 to 8 years) and, is the
of the ovary and testis with a dramatic increase in gonadal steroid production
and reproductive capability. In girls, gonadarche is manifested by breast
development and the onset of menstruation (menarche). Boys undergo testicular
enlargement and virilization.
Both growth hormone and the sex steroids, particularly estrogen, are
necessary for the normal adolescent growth spurt.
In general girls are skeletally mature at 14 ½ years of age and
boys at 16 ½
Growth usually ceases before the physes close. At the end of growth the
physes may be open even though the individual has ceased growing.
While the patient is prepubital chronological age is a reasonable indicator
of bone age. Patients from birth to age three or four years can be assumed
to be growing very fast. After this until they hit the adolescent growth
spurt, growth is much slower.
As the child approaches eight years of age, adrenarche provides some indication
of impending puberty. As children approach the growth spurt, it is helpful
to ask questions about the initiation of breast development or about rapid
The first signs of puberty and the rapid growth spurt are initial breast
development in girls and rapid foot growth in both boys and girls.
The rapid growth spurt occurs while the triradiate cartilages are still
open. The triradiate cartilage closes at about age 12. For scoliosis,
include the acetabulum on films taken for this reason. If there are concerns
about the additional radiation, then a careful assessment of hand skeletal
age should be obtained.
X Ray indicators of Skeletal Maturity
1: Ossification Centres about the elbow
Are useful in the younger prepubital child up until the age of 11 years.
At this stage the child has not reached the prepubital growth spurt, and
they are thus of limited use in determining the progression of a scoliotic
curve. With injuries to the elbow however knowledge of the growth center
here is essential in order to distinguish a fracture from an growth center.
With elbow injuries in children always x ray the normal side for comparison.
Displacements or of the ossification centres / fractures can easily be
missed if this is not done. The age of the child can also be determined
by the ossification centers.
There are 6 ossification centers around the elbow joint. These ossification
centers all appear at different ages and they all fuse to the adjacent
bones at various ages. It is not clinically important to memorize the
specific ages of when these ossification centers appear or fuse. However,
it is clinically important to realize that the ossification centers always
appear in a specific sequence.
The mnemonic of the order of appearance of the individual ossification
centers is C-R-I-T-O-E: Capitellum, Radial head, Internal (medial) epicondyle,
Trochlea, Olecranon, External (lateral) epicondyle. Remember that the
anatomic position of the body places the upper extremities in external
rotation (supination at the elbows) such that the antecubital fossa faces
anteriorly. Thus, the external epicondyle is on the radial side of the
elbow, while the internal epicondyle is on the ulnar side of the elbow.
The ages at which these ossification centers appear are highly variable,
but as a general guide, remember 1-3-5-7-9-11 years.
2: Risser’s Sign
The Risser sign, which is commonly used as a maturity indicator in scoliosis,
is based on the radiographic excursion of iliac apophyseal ossification.
The iliac apophysis typically starts ossifying at the anterior superior
iliac spine and
then extends posteriorly toward the posterior superior iliac spine.
The axial skeleton matures a few years later than the limbs, and for
scoliosis, the Risser sign is a useful method of bone age determination.
Skeletal age can be determined by the appearance of the iliac apophysis
of the pelvis. The apophysis appears laterally on a pelvic x ray, and
moves towards the spine as the patient approaches adulthood. Risser's
sign is a measures the growth left in the spine - this may help to determine
the potential for progression of scoliosis
Grading (based on iliac crest divided into 4 quadrants)
o Risser 1: 25% iliac apophysis ossification Anterior
Superior iliac spine (anterolateral) Seen in prepuberty or early puberty.
o Risser 2: 50% iliac apophysis ossification Ossification
extends halfway across iliac wing Seen immediately before or during growth
o Risser 3: 75% iliac apophysis ossification.
o Risser 4: 100% ossification, with no fusion to iliac
crest . Indicates slowing of growth
o Risser 5: Iliac apophysis fuses to iliac crest Indicates
cessation of growth.
Risser 1 is seen at age 13.8 in girls and 15.2 in girls. Risser 5 is first
seen at age 16 in girls and 18 in boys.
3. Hand and Wrist Bone X Rays
A common and accurate way of skeletal age measurement is to compare x
rays taken of the left hand and writ to standardized X ray pictures in
the Greulich and Pyle atlas. The Greulich and Pyle atlas has the advantage
of being universally available and has good instructions accompanying
One problem with this atlas is that there is some user variability, which
makes a precise estimation difficult. It was compiled using Caucasian
children in America and the data may not always extrapolate to races with
Age determination in other areas
Other age determination systems are of value to the criminologist and
immigration officials. It is sometimes crucial to determine if the individual
is over 18 or 21, or at whatever age defines adulthood, and its attendant
less lenient judicial treatment.
The third molar roots appear on x rays at age 18 years. The ossification
of the sternal clavicular cartilage also occurs at age 18 years.
1. Greulich WW, Pyle SI: Radiographic
Atlas of Skeletal Development of the Hand and Wrist, 2nd edition. Stanford,CA:
Stanford University Press, 1959.
2: Sanders JO, Browne RH, McConnell SJ, Margraf SA, Cooney TE,
Finegold DN. Maturity Assessment and Curve Progression in Girls
with Idiopathic Scoliosis. J Bone Joint Surg Am 2007;89:64-73.
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