Imaging characteristics of too-long anterior process syndrome in children and adolescents.

TLAP is common among control subjects. Therefore, a variant appears to be the most plausible explanation and it can be considered a mild form of calcaneonavicular coalition. However, in conjunction with symptoms suggestive of TLAP syndrome, the diagnosis is further supported by imaging, specifically with a calcaneonavicular space measurement of less than 3.2 mm. This measurement is most accurately obtained using CT with 2-dimensional reconstructions in all three planes. The simultaneous presence of the "anteater nose" sign, the talar beak, or the tapered anterior calcaneal process provides additional diagnostic evidence. In the diagnostic approach of calcaneonavicular coalition, oblique foot radiography seems useful in initially detecting abnormal coalition (bony or not), and complementarily, CT emerges as the best modality to characterize TLAP syndrome.