The brachial plexus (BP) innervates the upper limb
The BP originates from five spinal nerve roots: C5 to T1
The shoulder is innervated by the suprascapular nerve and the axillary nerve. They both originate from the spinal nerve roots C5 and C6
Anaesthesia of the shoulder requires blockade of the BP proximal to the level of the trunks, because the suprascapular nerve branches off the superior trunk
The brachial plexus is displayed with the suprascapular nerve (red arrow) and the axillary nerve (blue arrow). The five spinal nerve roots of the brachial plexus are indicated by C5 to T1. Green asterix = superior trunk; red asterix = middle trunk; blue asterix = inferior trunk.
