title: Gas dissection into the psoas associated with Knutsson's sign.
mesh_terms: D000388:Air; D006801:Humans; D007405:Intervertebral Disc Displacement / Q000000981:diagnostic imaging*; D008159:Lumbar Vertebrae / Q000000981:diagnostic imaging; D008297:Male; D008875:Middle Aged; D009132:Muscles / Q000000981:diagnostic imaging; D014057:Tomography, X-Ray Computed