and ulna, the metacarpals and phalanges of the 1st, 3rd, and 5th fingers, and all of the carpal bones except the pisiform. Knee maturation An atlas based on knee maturation has also been compiled. Hemiskeleton method The bones in the hand a wrist in a newborn do not change much in the first year of life. However, most pediatric radiologists still use the Greulich and Pyle technique for estimating bone age in infancy. 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. One common method based on x-rays of the hemiskeleton is the Sontag method. This technique was created to avoid errors in estimating bone age though to arise from focusing on only one area of the body. 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. Then, a radiologist counts the number of ossification centers present and uses a chart to convert the sum of ossification centers to a bone age. There is a chart for males and another for females with possible bone ages ranging from 1 month to 5 years. Since most of the ossification centers counted using this technique appear early in life, this method is only valid for measuring bone age up to around 5 years of age. Evaluation of cervical vertebrae Lamparski (1972) used the cervical vertebrae and found them to be as reliable and valid as the hand-wrist area for assessing skeletal age. He developed a series of standards for the assessment of skeletal age for both males and females. This method has the advantage of eliminating the need for additional radiographic exposure in cases where the vertebrae have already been recorded on a lateral cephalometric radiographic. This method is called the Cervical vertebral maturation method Hassel & Farman (1995) developed an index based on the second, third, and fourth cervical vertebrae (C2, C3, C4) and proved that atlas maturation was highly correlated with skeletal maturation of the hand-wrist. Several smartphone applications have been developed to facilitate the use of vertebral methods such as Easy Age. Clinical significance Assessment of a patient's bone age is used in pediatric medicine to help determine if a child is growing normally. Large differences between a person's bone age and their chronological age