Fig. 5From: Surgical anesthesia with a combination of T12 paravertebral block and lumbar plexus, sacral plexus block for hip replacement in ankylosing spondylitis: CARE-compliant 4 case reportsUltrasonography of the sacral plexus bathing in local anesthetic deep to the pirifomis muscle and medial to the PBI. (LA = Local anesthetic, PBI = posterior border of ischium, triangle indicates the needle)Back to article page