Table 4.

Adjustment required for primary and secondary angles for different patient positions

Patient position	Primary angle	Secondary angle
Supine—head first	α1	α2
Supine—feet first	−α1	-α2
Prone—head first	π + α1	α2
Prone—feet first	π − α1	−α2
Left lateral—head first	π/2 + α1	α2
Left lateral—feet first	π/2 + α1	−α2
Right lateral—head first	−π/2 − α1	α2
Right lateral—feet first	−π/2 − α1	−α2