Reflect the pectoralis major muscle.

1. Slip your fingers under the free (inferior) border of the pectoralis major muscle (if necessary, use your scissors to incise the deep fascia at the inferior border of the muscle).
2. Use your fingers to free the muscle from the underlying structures proceeding from lateral to medial.
3. Use your scissors to detach the pectoralis major from its sternal and clavicular attachments.
4. As you reflect the muscle laterally (do not cut the humeral attachment), you will encounter small pectoral vessels and nerves.  Cut the vessels and nerves as close to the muscle as possible.