Objective
We used the radiologic foot mapping system to evaluate the characteristics of hallux valgus.

Method
We studied the radiographs of 47 feet of 29 patients who had the hallux valgus. The weight bearing foot AP and lateral views of both sides were taken. The hallux valgus angle, first and second, first and fifth, and second and fifth metatarsal angles were measured with conventional methods. In addition we measured metatarsus primus varus (MPV) and proximal first metatarsal inclination (PFMI) angles. On lateral views, we measured calcaneal pitch, talar pitch and arch depth. By mapping system, we marked T1 through T5, MH1 through MH5, MB1 through MB5, CC, TN and NC, respectively.

Results
The first and fifth metatarsal angles were significantly larger in the patients with hallux valgus (p＜0.05). The metatarsus primus varus angle was significantly larger in the patients with hallux valgus (p＜0.05). The X coordinates at T1 and MH1 were significantly larger in the patients with hallux valgus (p＜0.05). The Y coordinates of the MB1, NC and TN were significantly larger negative values in the hallux valgus patients (p＜0.05).

Conclusion
In hallux valgus, the first metatarsocuneiform joint is the site of origin of metatarsus primus varus. The lateral splaying was present from the 5th toe to tarsal bones in hallux valgus groups.