Navicular body fracture classification

The present popular classification of navicular fractures is composed of three basic types with a subclassification for body fractures suggested by Sangeorzan.
(A) Avulsion-type fracture can involve either the talonavicular or naviculocuneiform ligaments.
(B) Tuberosity fractures are usually traction-type injuries with disruption of the tibialis posterior insertion without joint surface disruption.
(C) A type I body fracture splits the navicular into dorsal and plantar segments.
(D) A type II body fracture cleaves into medial and lateral segments. The location of the split usually follows either of the two intercuneiform joint lines. Stress fractures are usually be included in this group.
(E) A type III body fracture is distinguished by comminution of the fragments and significant displacement of the medial and lateral poles.