The fascia around the nerve bundle of brachial plexus is derived from
Preveebral fascia
Deep cervical fascia
Clavipectoral fascia
Pectoral fascia
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
Upper limb