The intercostal island flap is a new omnipotential flap that is extremely valuable for torso reconstruction, provided one understands the intricacies of intercostal anatomy. Human cadaver dissections were done to determine the precise course and branching pattern of the lower (T7-T11) intercostal neurovascular bundles. On the basis of these dissections, the intercostal structures can be divided into four anatomical segments: vertebral, costal groove, inter-muscular, and rectus. The anatomical segments can be safely combined in many ways to create versatile skin flaps. Three different clinical applications with requisite modifications in surgical technique are described in detail to exemplify important anatomical observations. The potential value of the intercostal island flap in reconstructive surgery is discussed.