RT Book, Section
A1 Jochum, Denis
A2 Atchabahian, Arthur
A2 Gupta, Ruchir
SR Print(0)
ID 57262519
T1 Chapter 131. Brachial Plexus
T2 The Anesthesia Guide
YR 2013
FD 2013
PB The McGraw-Hill Companies
PP New York, NY
SN 978-0-07-176049-2
LK accessanesthesiology.mhmedical.com/content.aspx?aid=57262519
RD 2024/04/24
AB Two  independent  layers  from  the  roots  to  terminal  branches:  A  simple  and  constant  dorsal  layer:  extensor  and  supinator  musclesA  complex  and  variable  ventral  layer:  flexor  and  pronator  muscles:  This  explains  the  variations  and  the  relationships  between  the  median,  musculocutaneous,  and  ulnar  nervesThe  brachial  plexus  can  be:  “Prefixed”  with  a  contribution  from  C4  (two  thirds  of  cases),  orNormal,  or“Postfixed,”  with  the  participation  of  T2Or  even  spread  in  both  directions:  Clinical  significance  of  these  variations  because  motor  and  sensory  distributions  are  modifiedOrigin  of  the  trunks:  Upper  trunk:  confluence  of  the  ventral  branches  of  C5  and  C6  (C4  participation,  prefixed  plexus)Middle  trunk:  ventral  division  of  C7Lower  trunk:  confluence  of  the  ventral  branches  of  C8  and  T1Constitution  of  the  cords  (most  common  configuration):  Lateral  cord:  confluence  of  ventral  divisions  of  upper  and  middle  trunks  (80%  of  cases)Medial  cord:  ventral  division  of  lower  trunk  (95%  of  cases)Posterior  cord:  confluence  of  dorsal  divisions  of  the  three  trunks  (70%  of  cases)Constitution  of  terminal  nerves  =  branches  (at  distal  edge  of  the  pectoralis  minor  muscle):  Posterior  cord:  posterior  plane  of  the  brachial  plexus,  with  mainly  radial  and  axillary  nervesLateral  and  medial  cords:  anterior  plane  of  the  brachial  plexus  with  mainly  the  median  nerve,  as  well  as  musculocutaneous  and  ulnar  nerves