Patient selection: from 1 month to 4 years of age
Landmarks:
(1) center of the metaphysis for the femur
(2) Hilgenreiner's (or Y) line through both triradiate cartilages of the hips (through the inferior boney margins of the ilia at the point of origin of the acetabular roof)
(3) vertical line (lying perpendicular to Hilgenreiner's line) through the lateral edge of the ischium
Yamamuro A (distance h1) =
= vertical distance from center of the metaphysis to Hilgenreiner's line in mm
Yamamuro B (distance d1) =
= horizontal distance from center of the metaphysis to the vertical line at the lateral edge of the ischium in mm
Interpretation:
• Boniforti et al list the normal range for Yamamuro A as 8 to 10 mm. Tonnis reports 6 to 14 mm with the distance abnormal if < 6 mm.
• Boniforti et al list the normal range for Yamamuro B in boys as 5 to 12 mm. Tonnis reports 5 to 13 mm with the distance abnormal if > 13 mm.
• Boniforti et al list the normal range for Yamamuro B in girls as 5 to 12 mm. Tonnis reports 4 to 12 mm with the distance abnormal if > 12 mm.
Performance:
• The measurements of Yamamuro and Chene are less affected by improper positioning of the femur than the measurements of Hilgenreiner and Erlacher (page 109, Tonnis).
