The infraspinatus muscle is innervated by the suprascapular nerve (C5-C6). This nerve originates from the upper trunk of the brachial plexus, passing through the suprascapular notch beneath the transverse scapular ligament and then traveling to supply both the supraspinatus and infraspinatus muscles. The primary action of the infraspinatus is external (lateral) rotation of the shoulder. It also plays a secondary role in stabilising the glenohumeral joint by compressing the humeral head into the