Spinalis Thoracis

Description

Running as the most medial column of the erector spinae, the spinalis thoracis is shown in posterior view within the deep vertebral groove, closely apposed to the thoracic spinous processes. Thoracic vertebrae are rendered segment by segment, with the ribs curving laterally from the costovertebral region to define the posterior thoracic cage. Bilateral scapulae sit superolateral to the thoracic spine, framing the paraspinal compartment and giving scale to the midline muscle belly and its cranio-caudal fiber direction. Spinalis thoracis matters because it is the paraspinal tissue you encounter and protect when planning midline posterior approaches to the thoracic spine, including laminectomy, posterior instrumentation, or decompression for thoracic myelopathy. Its attachments along the spinous processes place it in the tension band that resists flexion and helps maintain thoracic kyphosis, a relationship that becomes clinically visible in postural thoracic pain syndromes and in extension-based rehabilitation after compression fractures. Small muscle, big landmark. Use this artwork for gross anatomy and kinesiology teaching when differentiating the erector spinae columns (spinalis versus longissimus), for spine surgery atlases discussing midline exposure planes, and for radiology or MSK education that correlates paraspinal compartments with posterior thoracic bony landmarks on CT or MRI. Anatomical accuracy verified by SciePro's Medical Advisory Board.