TY - CHAP M1 - Book, Section TI - Chapter 139. Lumbosacral Plexus A1 - Jochum, Denis A2 - Atchabahian, Arthur A2 - Gupta, Ruchir Y1 - 2013 N1 - T2 - The Anesthesia Guide AB - The lumbar plexus is usually formed by the ventral rami of the L1–L3 and part of the ventral branch of L4The sacral plexus is formed by the lumbosacral trunk (L4, L5), the first sacral ventral ramus, part of the ventral branch of S2, and a small portion of the ventral branch of S3Classically, the ventral branch of L4 is the junction between the two plexi; it gives off a branch to the femoral nerve, one to the obturator nerve, and the lumbosacral trunk that becomes part of the sciatic nerveThere are several varieties of lumbosacral plexus: The most common is a “prefixed” plexus, including all or part of T12A “normal” plexusA “postfixed” plexusOr even a plexus spread in both directions: These anatomical variations can affect regional anesthesia practice because of variations in motor and sensory distributionsThe division into two planes of the lumbosacral plexus is less clear than for the brachial plexusThe two terminal branches of the lumbar plexus are the femoral nerve and obturator nerve, which correspond, respectively, to the dorsal and the ventral layersFor the sacral plexus, the tibial nerve is the ventral layer and the common peroneal nerve the dorsal layerThe layout of the main nerves of the lumbosacral plexus requires the use of combined blocks for anesthesia of the lower limb SN - PB - The McGraw-Hill Companies CY - New York, NY Y2 - 2024/03/28 UR - accessanesthesiology.mhmedical.com/content.aspx?aid=57262672 ER -