[Development of the normal infantile hip joints assessed by MRI]

The paper provides an overview of the time of appearance of the secondary ossification centers and closure of the growth plates of the acetabulum and proximal epiphysis of the femur: the triradiate cartilage, the acetabular roof growth cartilage, the subcapital growth cartilage, the growth cartilage of the major trochanter, the growth cartilage of the minor trochanter. The study is based upon 62 MRI scans of healthy hips in 45 patients aged 3-21. The examined hips showed no pathologic traits--neither in the MRI scan nor in X-ray investigation. In Spin Echo and Turbo Spin Echo sequential imaging all obtained slices were used, on GRADIENT ECHO: FISP 3D, FLASH 2D, and FLASH 3D FAT SAT only chosen slices were included in the study. This way the following results were obtained: the ossification center of the major trochanter appears at the age of 3 in girls and at the age of 6 in boys, while the ossification center of the minor trochanter appears at the age of 6 in both sexes. The times of complete ossification of following growth cartilages were observed: for the triradiate cartilage ossification was observed at age 12-15 in girls and 15-16 in boys; for the cartilage of the acetabular roof ossification was noted at age 12-15 in girls and 15-18 in boys; ossification in the subcapital growth cartilage occurred at age 15-17 in girls and 16-18 in boys; the major trochanter growth cartilage ossifies at age 15-16 in girls and 16-18 in boys; for the minor trochanter ossification of the growth cartilage occurs at age 14-16 in girls and at age 16-18 in boys. The secondary ossification center of the pubic bone appears at age 9-11 in girls and 13-16 in boys and the secondary ossification center of the acetabular roof appears at age 13-17 in girls and boys. This study expand our knowledge on the development of the hip joint and facilitate the assessment of hip pathology.