Figure 1. Left shoulder, patient placed in deck chair position, posterior view. A: the sterile fields are placed medial to the dorsal spine, leaving the space between the medial margin of the scapula and the spinous processes free. Using a skin marker, we delimit the acromion, the scapular spine, the medial margin of the scapula and the lateral border of the lower trapezius (arrow), which runs 45º with respect to the medial margin of the scapula; B: we trace the trajectory of a horizontal incision starting 2 cm medial to the medial margin of the scapula and extending 4 cm laterally, parallel to the lower border of the scapular spine.