Talar declination angle

The talar declination angle is drawn on the weightbearing lateral foot radiograph between the mid-talar axis and the supporting surface. It should usually measure approximately 21°.

If the first metatarsal axis is steep, the mid-talar axis approaches the horizontal and is projected above the first metatarsal. This indicates that the longitudinal arch is relatively high and there is pes cavus.

Conversely, where there is pes planus and a low arch, the first metatarsal axis is flattened and the mid-talar angle increases such that the mid-talar axis passes inferior to the first metatarsal.