Free surgical revision notes, diagrams and 3D

Brachial plexus anatomy: roots to branches, and the nerve lesions that follow

Brachial plexus for MRCS Part A with a 3D model: roots, trunks, divisions, cords and branches, Erb's and Klumpke's palsies and the classic nerve lesions.

• The ventral rami of C5–T1 form five roots, three trunks, six divisions, three cords and five terminal branches; the cords are named for their position around the second part of the axillary artery.
• Anterior divisions go to flexors and posterior divisions to extensors, so the posterior cord gives the axillary and radial nerves while the lateral and medial cords give the musculocutaneous, median and ulnar nerves.
• Branches that leave at root level (dorsal scapular, long thoracic) and trunk level (suprascapular) localise a lesion: if the rhomboids and serratus anterior still work, the injury is distal to the roots.