Table 3 Anatomical bone embedded frames

Tibia

y

The two malleoli and the head of fibula define a quasi frontal plane, the y axis is parallel to the line connecting the midpoint between LM and MM and the projection of the tibial tuberosity (TT) on this plane with its positive direction upward.

x

The line connecting lateral and medial malleoli (LM e MM) and y axis define a plane: x is orthogonal to that plane with its positive direction forward (obtained as product between the two above described lines).

z

Product between axis x and y.

Origin

Midpoint between LM and MM.

Hindfoot

z

Parallel to the line connecting ST and peroneal tubercle PT with its positive direction from left to right.

y

The line connecting calcaneus (CA) and substentaculum talii (ST) and the z axis define a plane: y axis is orthogonal to that plane with its positive direction upward (obtained as product between the two above described lines).

x

Product between axis y and z.

Origin

CA.

Midfoot

z

Parallel to the line connecting NT and C with its positive direction from left to right.

y

The line connecting (NT), and fifth metatarsal base (VMB) and z axis define a plane: y axis is orthogonal to that plane with its positive direction from proximal to distal segment (obtained as product between the two above described lines).

x

Product between axis y and z.

Origin

Midpoint between NT and C.

Forefoot

z

Parallel to the line connecting IMH and VMH with its positive direction from left to right.

y

The line connecting VMH and IIT and the z axis define a plane: y is orthogonal to the plane with its positive direction upward (obtained as product between the two above described lines).

x

Product between y and z.

Origin

Midpoint between IMH e VMH.

Foot

z

Parallel to the line connecting IMH e VMH with its positive direction from left to right.

y

CA, IMH and VMH define a plane; the line connecting IIT and CA belong to a plane perpendicular to the previous one; z axis is parallel to the line intersection between the two planes with its positive direction forward.

x

Product between axis y and z.

Origin

CA.