Spinalis Thoracis, Gross Anatomy

Description

Running longitudinally along the posterior thoracic vertebral column, the spinalis thoracis is highlighted as the medial column of the erector spinae, immediately adjacent to the thoracic spinous processes. Its muscle belly and tendonous slips track superiorly and inferiorly across multiple thoracic vertebrae, positioned medial to the longissimus thoracis and deep to the superficial back layers that would normally cover the midline. Lateral landmarks include the right scapula over the posterior ribs, while the upper pelvic girdle anchors the inferior field and clarifies the thoracolumbar continuity of the paraspinal musculature. Midline anatomy is clear. Spinalis thoracis often gets glossed over in dissection because it blends with semispinalis and the thoracolumbar fascia, yet it matters when you are teaching segmental extension and midline stabilization of the thoracic spine. This posterior view supports clinical discussions of thoracic paraspinal strain and myofascial pain patterns near the spinous processes, and it helps contextualize why midline approaches to the thoracic spine (including exposure for posterior instrumentation) must respect the layered erector spinae rather than treating it as a single undifferentiated mass. Palpation and needle-based procedures also live or die on this anatomy. Use this plate in gross anatomy and musculoskeletal back modules to distinguish spinalis from the more laterally placed erector spinae columns and to reinforce attachments to thoracic spinous processes. It also fits well in surgical anatomy teaching files, spine fellowship slide decks, and patient education materials on thoracic back pain where a precise medial paraspinal target is needed. Anatomical accuracy verified by SciePro's Medical Advisory Board.