Sectional neuroanatomy of the lower thoracic spine and chest

This is the fourth 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); and the third reviewed the middle thoracic spine and chest (T5-T8). The procedures performed in the lower thoracic spine include percutaneous biopsies of the liver and kidneys, percutaneous nephrolithotomy, spinal injections, radiofrequency ablations, electromyography of the diaphragm, trigger point injections, chemodenervation with botulinum toxin, acupuncture, aneurysm repair, and, occasionally, chest tube placement in the lower lung fields. Complications include subcapsular hematomas, infections, pneumothorax, hemothorax, spinal cord ischemia and resultant paraplegia, and, rarely, nephropleural fistulas. This article provides anatomically accurate schematics of innervations of the lower thoracic chest and spine (T9-T12) that can be used to interpret the magnetic resonance images of the muscles and the nerves. Cross-sectional schematics of the lower 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 lower thoracic chest and spine allows the physician to increase the accuracy and the efficacy of interventional procedures. This could also assist the electromyographer in correlating the clinical and electrophysiological findings with magnetic resonance images.