Spinalis Thoracis, Posterior View

Description

Running longitudinally along the posterior thoracic spine, the spinalis thoracis is highlighted as the most medial column of the erector spinae, closely apposed to the thoracic spinous processes. Lateral to it, the longissimus thoracis and iliocostalis components would be expected to form progressively more lateral muscle masses over the ribs, while the vertebral column remains the central skeletal landmark from the lower cervical region through the lumbar spine. Posterior thoracic ribs arc laterally from their vertebral articulations, and the scapulae sit posterolaterally over the rib cage, framing the upper thorax. Bony detail at the cranial end includes the occipital bone seen from behind. A posterior view makes the medial alignment of spinalis thoracis unambiguous, which is exactly what students struggle with when trying to distinguish it from longissimus on cross-section or in dissection. Clinically, the erector spinae mass is a common target for thoracic paraspinal approaches and for ultrasound guided erector spinae plane blocks, where the relationship of the muscle columns to the thoracic spinous processes and ribs informs needle trajectory and spread of local anesthetic. Midline pain patterns and postural overload are often discussed in relation to these deep extensors. Use this artwork for gross anatomy and kinesiology teaching on intrinsic back musculature, for surgical or anesthesia texts describing thoracic paraspinal anatomy, and for patient facing materials explaining paraspinal muscle strain in the upper back and chest wall region. Anatomical accuracy verified by SciePro's Medical Advisory Board.