30 Suprascapular Nerve Block
The suprascapular nerve arises from the superior trunk of the brachial plexus, containing contributions from the C5 and C6 ventral rami. The nerve innervates the supraspinatus and infraspinatus muscles and contains articular branches from the shoulder joint. Cutaneous innervation of the suprascapular nerve is not common, being demonstrated in about 15% of subjects.1,2 When present, the cutaneous distribution is similar to the usual distribution for the axillary nerve.
The suprascapular nerve is about 2 to 3 mm in diameter.3 The suprascapular nerve diverges distally 2 cm from the junction of C5 and C6 into the superior trunk (range, 0-2.5 cm). The distance measured from the origin of the suprascapular nerve to the clavicle is variable (range, 0.5-7.5 cm).4 Recognition of the takeoff of the suprascapular nerve from the brachial plexus is important for complete brachial plexus blocks when performed low in the neck. Suprascapular nerve blocks can provide some analgesia after shoulder surgery, but this effect is small.5 More distal block of the suprascapular nerve near the spinoglenoid notch is potentially more selective, but the nerve and needle imaging for this procedure can be challenging.
