Spinalis Thoracis Muscle, Posterior View

Description

Running immediately lateral to the thoracic spinous processes, the spinalis thoracis appears as a narrow, cord-like column within the erector spinae mass, extending superior to inferior along the posterior thorax. A posterior view also brings the occipital bone and upper cervical vertebrae into continuity with the thoracic vertebral column, while the scapulae sit posterolaterally over the rib cage, their medial borders paralleling the ribs. The posterior ribs and costovertebral region frame the muscle laterally as it tracks close to the midline. Midline anatomy is the point. Because spinalis thoracis lies so near the spinous processes, this view helps distinguish it from longissimus thoracis, which occupies a more lateral position and relates more directly to the rib angles and transverse processes. That distinction matters in teaching layered back anatomy and in procedural planning, since thoracic paraspinal injections, medial branch blocks, and posterior approaches to the thoracic spine rely on consistent surface-to-deep relationships around the spinous processes, laminae, and costotransverse joints. Posterior midline tenderness or spasm after strain often localizes to the erector spinae complex, and seeing spinalis thoracis in situ clarifies why symptoms cluster close to the vertebral column. Ideal use cases include gross anatomy labs covering intrinsic back muscles, kinesiology modules on spinal extension and postural control, and textbook figures contrasting the erector spinae columns across cervical, thoracic, and lumbar regions. It also fits spine surgery or interventional pain publications that need an uncluttered posterior orientation to midline thoracic landmarks. Anatomical accuracy verified by SciePro's Medical Advisory Board.