Level Components Key Nerves / Muscles Clinical
Dorsal scapular (levator
Erb’s palsy (C5–C6),
Roots C5–T1 scapulae, rhomboids), Long
Klumpke’s (C8–T1)
thoracic (serratus anterior)
Superior (C5–C6), Shoulder dystocia
Trunks Middle (C7), - → superior trunk
Inferior (C8–T1) lesion
Posterior →
Anterior &
Divisions Form cords extensor
Posterior
compartment
Lateral →
Musculocutaneous, part of Axillary nerve →
Lateral, Medial,
Cords Median; Medial → Ulnar, part shoulder abduction,
Posterior
of Median; Posterior → radial → wrist drop
Axillary, Radial
Major terminal Musculocutaneous, Median,
Branches Key clinical lesions
nerves Ulnar, Axillary, Radial
Clinical Pearls
Erb’s palsy: C5–C6, “Waiter’s tip” (arm adducted, internally rotated, pronated
forearm)
Klumpke’s palsy: C8–T1, claw hand (4th & 5th fingers)
Wrist drop: Radial nerve lesion
Ape hand: Median nerve lesion
Claw hand: Ulnar nerve lesion
Mnemonics
Brachial plexus order: Randy Travis Drinks Cold Beer → Roots, Trunks,
Divisions, Cords, Branches
Terminal nerves by cord: Lateral → Musculocutaneous, part of Median;
Medial → Ulnar, part of Median; Posterior → Axillary, Radial
Brachial Plexus High Yield notes 1