Axillary sheath is derived from
-The muscular floor of the posterior triangle is covered by preveebral layer of fascia colli. -It forms the axillary sheath around subclan aery and brachial plexus travelling from the root of neck to the upper limb. -reference: Textbook of anatomy, Head Neck, and brain, Vishram Singh, 2nd edition, page no.80
Upper limb
Preveebral fascia
Pretracheal fascia
Investing layer of deep cervical fascia
Deep fascia of throacic wall
Preveebral fascia