Overview Introduction Standard: C5, C6, C7, C8, T1 – 77% of patients Prefixed: Prefixed (contributions from C3, C4) – 22% Postfixed (roots caudal to T1) – 1% COMPOSITION: “Robert Turner Drinks Cold Beer” Roots (5): ventral rami of C5-T1, superior and posterior to subclavian login to view 2 more bullets Trunks (3): emerge from triangle formed by anterior scalene, middle scalene, first rib login to view 8 more bullets Divisions (6): 3 anterior, 3 posterior (each trunk gives 1 anterior and 1 posterior division) Cords (3): login to view 19 more bullets