UFCB01

Length

Measured from proximal aspect of femoral head to distal aspect of femoral condyles, using transverse images; formerly done with calipers

UFCB02

Tt.Ar

Area enclosed by periosteal perimeter; includes all bone, marrow, and porosity.  Also

Called the sub-periosteal area.

UFCB03

Ma.Ar

Area enclosed by endocortical perimeter.  Also called sub-endosteal area.

UFCB04

Ct.Mask

Area between periosteal and endocortical surfaces, including porosity. 

UFCB05

Ct.Ar

Cortical bone area excludes porosity from the cortical mask.  This is the cortical mask minus porosity and is also called the segmented bone area.

UFCB06

Ps.Pm

Red ellipse.  Calculated by dividing periosteal surface area of a short span of diaphysis by the diaphyseal span length of diaphyseal span length

UFCB07

Ec.Pm

Blue ellipse.  Calculated indirectly due to irregular endocortical boundary; marrow area is assumed circular to calculate this perimeter, see error in circular approximation

UFCB08

Po.Ar

Total absolute cross-sectional area of intra-cortical porosity at mid-diaphysis.
Importantly, this is calculated on a volumetric basis to accurately capture 3D
pore volumes, and calculated back to area by dividing by the diaphyseal

length of the selected volumetric region of interest.  Also called cortical porosity.

UFCB09

Ct.Po

Ratio of pore area to Cortical Mask

UFCB10

Ct.Th

Direct measurement of mid-diaphysis cortical thickness. This is calculated on a volumetric basis to obtain a highly accurate measure of average thickness

UFCB11

J

Geometric measurement of bone stiffness in twisting; mathematically J = Imax + Imin.   Also referred to as the polar 2nd moment of area

UFCB12

Imax

Calculated about axis generally corresponding to anterior-posterior direction and thus lateral bending; geometric stiffness in lateral bending.  Also called the maximum bending moment of inertia at the mid-diaphysis about a centroidal cross-sectional axis that presents the greatest resistance to bending.

UFCB13

Imin

Calculated about axis generally corresponding to medial-lateral direction and thus anterior-posterior bending; geometric stiffness in anterior-posterior bending.   Also known as the minimum principal moment of inertia at the mid-diaphysis about a centroidal cross-sectional axis that presents the least resistance to bending. This largely coincides with the medial-lateral anatomical axis, or bending in the anterior-posterior plane (which is typically the direction used for mechanical testing).

UFCB14

Zmax

Ratio of Imax to half major diameter perpendicular to axis defining Imax; geometric strength in medial-lateral bending.  Also known as a measure of geometric bending strength for flexure about the minimum principal axis (medial-lateral) or Ratio of Imin / Cmin (section modulus, Z).

UFCB15

Zmin

UFCB16

App.D

mg of hydroxyapatite per cubic cm of cortical mask; nearly identical to tissue densiry for low intracorticy porosity; typically not reported.  Hydroxyapatite (HA) calibrated true volumetric mineral density of cortical bone is normalized to the volumetric cortical mask. Apparent density includes all intracortical porosity and is thus an “apparent” density.

UFCB17

Tiss.D

Tissue density of cortical bone matrix only, excluding segmented intracortical porosity; mg of hydroxyapatite per cubic cm of mineralized bone matrix.  Hydroxyapatite (HA) calibrated true volumetric mineral density of cortical bone tissue, normalized to the volumetric cortical bone area, excluding intra-cortical porosity. A double layer of surface voxels are also excluded from all free surfaces (periosteal, endosteal, individual pores) to eliminate partial volume artifact.

UFCB18

Dmax

UFCB19

Dmin