The long thoracic nerve origins from the spinal nerve roots C5, C6 and C7
The upper two roots typically pierce the middle scalene muscle and the lower passes anterior to the muscle
The components of the nerve enter the axilla behind the brachial plexus and descend approximately in the midaxillary line; it runs on the superficial surface of the serratus anterior muscle which it innervates.
Long thoracic nerve (cyan arrow), serratus anterior muscle (green arrows), major pectoral muscle (yellow asterix), minor pectoral muscle (black arrow), latissimus dorsi muscle (green asterix)
