This is the third in a series of articles on the spine. The first reviewed the anatomy of the neck. The second reviewed the upper thoracic spine and chest (T1-T4). A fourth article is planned for the lower thoracic spine. Procedures in the midthoracic spine include chest tube placement, trigger point injections, chemodenervation with botulinum toxin, video-assisted thoroscopic surgery, and spinal injections. Complications include pneumothorax, hemothorax, diaphragmatic irritation, sympathetic trunk irritation, postthoracotomy pain, and intradural abscesses. This article provides anatomically accurate schematics of innervations of the middle thoracic chest and spine (T5-T8) that can be used to interpret magnetic resonance images of the muscles and nerves. Cross-sectional schematics of the middle thoracic chest and spine were drawn as they appear on imaging projections. The relevant nerves were color coded. The muscles and skin surfaces were labeled and assigned the color of the appropriate nerves. An organized comprehensive map of the motor innervation of the middle thoracic chest and spine allows the physician to increase the accuracy and efficacy of interventional procedures. This could also assist the electromyographer in correlating the clinical and electrophysiologic findings with magnetic resonance images.