Fig. 3
From: Posterior intercostal flap: an anatomical study and best flap design
A photograph of the right side of the back showing a vertical raw of 4 intermediate zone musculocutaneous perforators (Pi) appearing at the lateral border of erector spinae (Es). They are the 6th to 9th space perforators. They pass through the back muscles, reach the skin, and ramify into it. The 9th space medial zone perforator (Pm) is seen at the medial border of Es. The serratus posterior inferior muscle (SPI) was reflected with the skin. M is the midline of the back