RT Journal Article SR Electronic T1 Morphological Findings of Asymmetrical and Dystrophic Psoas and Piriformis Muscles in Chronic Lower Back Pain during CT Guided Botulinum Toxin Injections JF Regional Anesthesia & Pain Medicine JO Reg Anesth Pain Med FD BMJ Publishing Group Ltd SP 104 OP 104 DO 10.1136/rapm-00115550-199823031-00104 VO 23 IS Suppl 1 A1 Samuel K. Yue YR 1998 UL http://rapm.bmj.com/content/23/Suppl_1/104.abstract AB