Rhomboid Major Muscle Under the Skin, Posterior View

Description

Posterior surface anatomy of the upper thorax is presented with the skin retained, while the mid-scapular layer is emphasized in color to orient the viewer to the scapular retractors. Medial fibers of the trapezius (pars transversa) span from the spinous processes of the mid thoracic vertebrae toward the acromion and spine of the scapula, lying superficial to the rhomboid major. Deep to that plane, the rhomboid major runs obliquely from the spinous processes of T2 to T5 to the medial border of the scapula, inferior to the rhomboid minor and medial to the posterior deltoid. Clear landmarks. This posterior perspective matters when you need to distinguish scapular retraction generated by trapezius versus rhomboid major, because they share the same movement goal but differ in depth, fiber direction, and innervation (spinal accessory nerve for trapezius, dorsal scapular nerve for rhomboids). Dorsal scapular neuropathy and C5 radiculopathy can both present as medial scapular border pain and weak retraction, and this layering helps explain why palpation and manual testing can misattribute symptoms to the trapezius when the rhomboid major is the primary generator. Clinicians teaching scapular dyskinesis also benefit from the spatial relationship of these muscles to the thoracic spinous processes and the medial scapular border. Use this illustration in gross anatomy and kinesiology courses to teach posterior thoracic wall musculature, in physical therapy and sports medicine materials on posture and scapular stabilization, and in procedure guides discussing interscapular trigger point injection or EMG electrode placement where depth and fiber orientation determine targeting. Anatomical accuracy verified by SciePro's Medical Advisory Board.