The fascia around the nerve bundle of brachial plexus is derived from
High-Yield Explanation
The fascia around the brachial plexus is called axillary sheath and is a derivative of preveebral fascia Axillary sheath covers brachial plexus and axillary vessels Axillary sheath localises the anesthetic solution to the nerve plexus. Ref : Gray's Anatomy The Anatomical Basics of Clinical Practice 41 e pg 777