Sonoanatomy revisited: the long thoracic nerve.

The long thoracic nerve (LTN) arises from the C5, C6 and C7 roots and innervates the serratus anterior muscle. Scapular winging is the landmark manifestation of LTN neuropathy and may develop after an accidental injury during selective cervical nerve root or inter-scalene brachial plexus blocks. Although its sonoanatomy has been described in the previous literature, how to gradually identify the entire nerve course has rarely been discussed. In this regard, the present paper aims to elaborate the scanning method of the LTN from its origin to its distal segment.