Spinalis Thoracis Muscle

Description

Running parallel to the spinous processes of the thoracic vertebrae, the spinalis thoracis forms the most medial column of the erector spinae complex, positioned just lateral to the midline and posterior to the rib cage. Fibers extend superior to inferior across the mid thoracic region, with segmental attachments along thoracic spinous processes, while the ribs curve laterally from the vertebral column to frame the posterior thorax. Scapulae sit posterolaterally over the upper ribs, providing surface landmarks for the thoracic back even when the emphasis remains on the paraspinal muscle band. Clean, vertical architecture. Spinalis thoracis is often underrepresented in broad “back muscle” diagrams, yet it is a practical teaching target when explaining how thoracic extension and segmental stabilization differ from lumbar mechanics, where multifidus and the larger iliocostalis and longissimus components tend to dominate discussion. This medial erector spinae strip also matters in posterior approaches to the thoracic spine, where the muscle-splitting corridor close to the spinous processes can reduce lateral dissection but increases reliance on precise midline landmarks to avoid drifting toward the costotransverse region. Correlating the muscle’s line of pull with thoracic kyphosis and postoperative paraspinal pain patterns makes the anatomy stick. Use this illustration in gross anatomy and kinesiology modules covering the intrinsic back muscles, and in spine surgery or rehabilitation texts discussing posterior thoracic exposure, paraspinal denervation, and targeted strengthening for thoracic extensor endurance. It also suits lecture slides on the erector spinae subdivisions when you need a clear medial-to-lateral orientation against the thoracic vertebrae and rib cage. Anatomical accuracy verified by SciePro's Medical Advisory Board.