Lower Intercostal Nerves, Transversalis, & Rectus Abdominis Muscles

Illustration from 'Surgical Anatomy: The Treatise of the Human Anatomy and Its Applications to the Practice of Medicine and Surgery, volume III' (by Dr. John Blair Deaver) shows the lower intercostal nerves which supply the Intercostales and abdominal muscles, the last three sending branches to the Serratus posterior inferior, 1903. About the middle of their course they give off lateral cutaneous branches. The transversus abdominis muscle, also known as the transverse abdominus, transversalis muscle and transverse abdominal muscle, is a muscle layer of the anterior and lateral abdominal wall which is deep to (layered below) the internal oblique muscle. It is thought to be a significant component of the core. The rectus abdominis muscle is a paired muscle running vertically on each side of the anterior wall of the human abdomen. . (Photo by VintageMedStock/Getty Images)