Fig. 5
From: An analysis of the foot in turnout using a dance specific 3D multi-segment foot model
Diagram depicting an abducted first MTPJ in the transverse plane. The dark grey circles represent the anatomical retro-reflective markers and the light grey circles represent the calculated midpoints. Note: MTB1, base of the first metatarsal (anatomical/tracking marker); MT1, head of first metatarsal (anatomical/calibration marker); MidMet, midpoint between MTB1 and MT1 (virtual marker); XMET, a virtual marker on the end of the x-axis defined by the vector joining the metatarsal origin (MT1) and MTB1, and pointing anteriorly; HAL, middle of the dorsal aspect of the hallux nail (anatomical/tracking marker); MT5, head of the fifth metatarsal (anatomical/tracking marker); FTML, intermedius forefoot, mid-point between MT1 and MT5 (virtual marker)