6% of exams performed, including 78 calcaneonavicular coalitions.
Secondary signs evaluated for calcaneonavicular coalitions were similar to those utilized in plain radiographic evaluation: blunted or flat anterior calcaneal process (10) (Figs.
3% (8/78) of the calcaneonavicular coalitions demonstrated the well-known "anteater" sign, while 24.
All but two of those cases were calcaneonavicular in location (Table 5).
10,22,24,25) Calcaneonavicular coalitions ossify earlier and become symptomatic around 8 to 12 years of age.
8,9,21,29,30) Calcaneonavicular and talocalcaneal (subtalar) coalitions are accepted as the two most common types, but opinion varies regarding relative distribution and histologic subtype.
Although it is uncommon for an os calcaneus secundarius to cause symptoms, range of motion of the subtalar joint may be limited by the ossicle, clinically resembling a calcaneonavicular coalition.
Calcaneus secundarius presenting as calcaneonavicular coalition: A case report.
Tears of the spring ligament (plantar calcaneonavicular ligament) can lead to a flatfoot deformity and inferior subluxation of the talar head.
Tear of the plantar calcaneonavicular (spring) ligament causing flatfoot.