Bone age

In children, bone age serves as a measure of physiological maturity and aids in the diagnosis of growth abnormalities, endocrine disorders, and other medical conditions.

[1][2][3] As a person grows from fetal life through childhood, puberty, and finishes growth as a young adult, the bones of the skeleton change in size and shape.

[4] Other uses of bone age measurements include assisting in the diagnosis of medical conditions affecting children, such as constitutional growth delay, precocious puberty, thyroid dysfunction, growth hormone deficiency, and other causes of abnormally short or tall stature.

[5][9] The first atlas published in 1898 by John Poland consisted of x-ray images of the left hand and wrist.

[7][8][16] The two most common techniques for estimating bone age are based on a posterior-anterior x-ray of a patient's left hand, fingers, and wrist.

[17][20] Finally, only the wrist and hand are imaged out of a desire to minimize the amount of potentially harmful ionizing radiation delivered to a child.

[2] In the United States, bone age is usually determined by comparing an x-ray of the patient's left hand and wrist to a set of reference images contained in the Greulich and Pyle atlas.

William Walter Greulich and Sarah Idell Pyle published the first edition of their standard reference atlas of x-ray images of the left hands and wrists of boys and girls in 1950.

[3][21] Images in the Greulich and Pyle atlas came from healthy white boys and girls enrolled in the Brush Foundation Study for Human Growth and Development between the years 1931 and 1942.

A drawback associated with the Greulich and Pyle method of assessing bone age is that it relies on x-ray imaging and therefore requires exposing the patient to ionizing radiation.

[21] Other downsides are that the atlas has not been updated since 1959 and the images in the atlas were acquired from healthy white children living in Cleveland, Ohio in the 1930s and 1940s and therefore may not yield accurate bone age assignments when applied to non-white patients or unhealthy children.

[1][2][21]The Tanner-Whitehouse (TW) technique of estimating bone is a "single-bone method" based on an x-ray image of a patient's left hand and wrist.

[11][7] Alternative techniques for estimating bone age in infancy include tallying the number of ossification centers present in the left half of the infant's body requiring a hemiskeleton x-ray.

[24] This technique was created to avoid errors in estimating bone age thought to arise from focusing on only one area of the body.

[24] The Sontag method uses x-rays of all the bones and joints of the upper and lower limbs on the left side of the body.

[24] Lamparski (1972)[25] used the cervical vertebrae and found them to be as reliable and valid as the hand-wrist area for assessing skeletal age.

Assessment of a patient's bone age is used in pediatric medicine to help determine if a child is growing normally.

Since bone age measurements are inherently approximations, they are conventionally reported with a standard deviation which serves as an estimate of the associated error.

[37] An advanced bone age is common when a child has had prolonged elevation of sex steroid levels, as in precocious puberty or congenital adrenal hyperplasia.

Formation of the human skeletal system begins in fetal life with the development of a loosely ordered connective tissue known as mesenchyme.

The carpal bones arise from primary ossification centers and continue their calcification in an outward manner.