Spinalis Thoracis Muscle, Posterior View

Description

Posterior thoracic and cervical musculature is presented in a male figure with emphasis on the spinalis thoracis, the medial column of the erector spinae group running adjacent to the thoracic spinous processes. Longitudinal fibers course superior to inferior, lying medial to longissimus thoracis and lateral to the spinous processes, with segmental attachments that align it closely with the thoracic vertebral midline. Superficially, the trapezius spans the posterior neck and upper back, while the rhomboid major is visible deep to trapezius, extending from upper thoracic spinous processes to the medial border of the scapula, drawing the scapula medially. Understanding this posterior relationship matters when teaching layered back dissection and when interpreting posterior thoracic pain patterns that can be mislabeled as scapular muscle strain. Spinalis thoracis is often discussed as a postural extensor and stabilizer of the thoracic spine, but this view also clarifies why EMG needle placement, trigger point palpation, and posterior midline approaches must respect its proximity to the spinous processes and interspinous spaces. Small muscle, tight corridor. Useful for gross anatomy labs covering the intrinsic back (epaxial) muscles, for surgical anatomy references describing posterior thoracic exposures, and for rehabilitation texts that differentiate erector spinae components from scapulothoracic muscles such as rhomboid major and trapezius. Anatomical accuracy verified by SciePro's Medical Advisory Board.