Fig. 4.

Type II accessory navicular. a Axial FSE T1 in a 37-year-old woman with history of tibialis posterior insufficiency. There is a type II accessory navicular, with irregularity in the articular facets of the synchondrosis, indicative of abnormal mobility / mechanical overload. b Axial fast spin echo proton density (FSE PD) fat sat in the same patient demonstrates increased signal intensity in keeping with edema in both aspects of the synchondrosis, indicating shearing and stress in the joint, which is associated to the tibialis posterior insufficiency