Steps to follow:

  1. Skin incision
  2. Orientation between the two heads of pectoralis major
  3. Identification of axillary vein
  4. Identification and excision of the subclavian muscle
  5. Complete dissection of the axillary vein up to the first rib
  6. Exposure of the first rib
  7. Transection of the anterior part of the first rib
  8. Transection of the posterior part of the first rib
  9. Division of the anterior scalene muscle (posterior to the axillary vein) close to the firt rib (Note: by dividing the ASM on the first rib there is no danger of injuring the phrenic nerve as, at this level, the nerve normally lies posterior the subclavian vein[2])
  10. Extraction of the first rib
  11. Complete mobilization of the axillary vein

References:

  1. https://www.youtube.com/watch?v=EIzjBcI2CUU&t=369s
  2. https://teachmeanatomy.info/neck/nerves/phrenic/