Table 1.

Nomenclature for parameters measured on standing lateral radiographs

Measurement	Abbreviation	Description
Hip axis	HA	Midpoint between approximate centers of both femoral heads. The other parameters measures in the study are measured from this point
Pelvic radius	PR	A distance from the HA to the posterior superior corner of S1
Pelvic radius line	PR Line	A line connecting the HA and the posterior superior corner of S1
Pelvic morphology	PR-S1	Angular measurement between the PR line and a tangent line along the S1 endplate
Pelvic angle	PA	Angular measurement between the PR line and a vertical line draw through the HA
Sacral translation	HA-S1	Horizontal distance between the vertical line troughs HA
Total lumbosacral lordosis	T12-S1	Angular measurement between inferior endplate of T12 vertebral body and superior endplate of S1
Total lumbopelvic lordosis	PR-T12	Angular measurement from the PR line and a tangent line along the inferior endplate of T12 vertebral body
Regional lumbopelvic lordosis	PR-L2, PR-L4, PR-L5	Angular measurement from the PR line and a tangent lines along the superior endplate of L2, L4 and L5, respectively