Longissimus Thoracis, Posterior View

Description

Posteriorly, the longissimus thoracis is highlighted as the intermediate column of the erector spinae, lying lateral to spinalis and medial to iliocostalis along the lower thoracic spine and lumbar region. Its muscle belly and longitudinal fiber direction are shown ascending from the thoracolumbar fascia and posterior iliac crest region toward the thoracic transverse processes and adjacent ribs. Overlying landmarks such as trapezius in the upper back and the posterior deltoid at the shoulder frame the field laterally, while gluteus maximus anchors the inferior midline. Clear separation of longissimus thoracis from iliocostalis matters when teaching extension versus ipsilateral lateral flexion mechanics and when explaining why paraspinal overuse pain often localizes a few centimeters off midline rather than directly over the spinous processes. Palpation and trigger point mapping commonly target this column in mechanical low back pain, and the posterior view aligns with how clinicians approach paraspinal assessment and manual therapy. For procedural context, this anatomy also orients readers to the muscle planes encountered during posterior midline approaches to the thoracolumbar spine, where multifidus lies deep and more medial while longissimus forms a substantial superficial paraspinal mass. Use this artwork in gross anatomy and kinesiology teaching to contrast the erector spinae columns and to correlate fiber direction with functional testing in spinal extension. It also fits well in rehabilitation texts, sports medicine handouts, and clinical education materials covering paraspinal strain, posture-related back pain, and posterior trunk surface anatomy. Anatomical accuracy verified by SciePro's Medical Advisory Board.