Anatomy · Upper Limb

Radial nerve: course, branches, distribution and lesions

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  • Radial nerve: continuation of the posterior cord of the brachial plexus, carrying fibres from C5 to T1 (T1 inconstant); largest nerve of the upper limb.

Course

Sequence

  • Posterior cord → teres major → lower triangular space → spiral groove → lateral intermuscular septum → anterior compartment of arm → cubital fossa → terminal division.
  • In the spiral groove the radial nerve lies in direct contact with the humerus.
  • At the level of the lateral epicondyle, in the cubital fossa, it terminates by dividing into superficial and deep branches.
  • In the axilla the radial nerve lies posterior to the third part of the axillary artery, anterior to the muscles forming the posterior wall of the axilla.
  • It enters the arm at the lower border of teres major.
    • Passes between the long and medial heads of triceps, through the lower triangular space, to reach the spiral groove with the profunda brachii artery.

Boundaries of the spiral groove