Positioning for neuraxial anesthesia

The sitting and lateral decubitus positions are used most commonly for spinal anesthesia. The sitting position may be particularly useful for larger patients, as the midline may be more easily estimated in this position if bony landmarks are not easily palpated. The patient should slouch symmetrically with shoulders over the hips to flex the spine.
For the lateral decubitus position, the thighs should be drawn up with the hips maximally flexed and the lower back rounded or pushed out.
The intercristal line (ie, a line between the iliac crests) is used as a rough guide for spinal needle placement. The needle should be inserted at or below this line to avoid spinal cord trauma.
For further details, refer to the topic on spinal anesthesia technique.