"type 1 (os tibiale externum, os naviculare secundarium):"
"type 2 (prehallux, bifurcate hallux):"
"type 2A: acute angle at the navicular tuberosity"
"type 2B: positioned more inferiorly"
"type 3:"
"triangular or heart-shaped; typically measures around 12 mm"
"The Geist classification is sometimes known as the Coughlin classification 3 after being published without an eponymous name in Mann’s Surgery of the Foot and Ankle (9th edition), edited by Michael J Coughlin et al. 4; however, this text has since published the Geist classification."
"History and etymology"