Covered femoral head area

The covered femoral head area is determined from a ventrodorsal radiograph of the hips. The dog is placed dorsal recumbency and the pelvic limbs are extended caudally, the femurs are parallel to each other. Positioning is considered satisfactory if :

• the pelvis is symmetrical (iliums and obturator foramina are symmetrical)

• the femur cortex pass through the middle of the sesamoid bones of the gastrocnemius muscle

• the patellas are centered on the trochlea of femur.

The measurement is usually made using medical image processing software: the covered femoral head area is calculated automatically after tracing the surface of the femoral head covered by the corresponding dorsal acetabulum and bounded laterally by the dorsal acetabular edge.