Dorr Classification; Bone 1993
"Structural and Cellular Assessment of Bone Quality of Proximal Femur"
A - Thick cortex - champagne flute canal
B - Thin cortex with residual funnel shape
C - Thin cortex - "stove pipe canal"
Canal/Canal Ratio
A - <0.5
B - 0.5 - 0.75
C - >0.75