Fig. 2
From: Endoscopic rhizotomy for chronic lumbar zygapophysial joint pain
a Dorsal medial branch was exposed. b Dorsal medial branch embodied in the thick periosteum. c Dorsal medial branch is in the transitional position between transverse process base and superior articular process. d Test branch with radio frequency head and repeat pain complaint. DMB, dorsal medial branch; PS, periosteum; SAP, superior articular process; TP, transverse process; RFH, radiofrequency head