Cone-shaped epiphyses in Japanese children

Cone-shaped epiphyses (CSE) are reported in left-hand radiographs of a sample of 1,399 otherwise normal Japanese children aged 5-11 years. CSE occurred in only three centers: distal thumb, mid-index finger, and mid-fifth finger. The overall frequency of 23% shows a female bias (32% to 16%), which disappears when mid-5 cones are excluded. Chi-squared analyses show significant gender bias for mid-5 cones alone or in combination with the other phalanges, and show significant center associations: CSE in distal-1 and/or mid-2 are more common in association with mid-5 cones than they are without mid-5 cones. The CSE female bias in mid-5 is essentially unchanged across age-cohorts when bone-age is controlled for precocity, and no significant trends in CSE frequency with age are noted for either gender.