Upper trunk

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Nerve: Upper trunk
Latin truncus superior plexus brachialis
/ Elsevier

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]


The upper trunk (or superior trunk) is a trunk of the brachial plexus which derives from the C5 and C6 roots.

Damage to the upper trunk causes

  • Arm hangs by side,
  • Elbow can’t flex,
  • Arm medially rotated,
  • Forearm pronated,
  • ‘waiter’s tip’,
  • Loss of sensation over deltoid (C5) and lateral upper limb (C6).

The musculocutaneous and median nerves derive largely from this trunk.