Deep Muscles of the Back

Description

Posterior trunk musculature is rendered with the superficial layers partially retained, so the trapezius spans from the occipital region and nuchal ligament inferiorly to the scapular spine, while the deltoid caps the lateral shoulder and blends anteriorly and posteriorly around the acromion. Inferior and lateral to the scapula, latissimus dorsi sweeps superolaterally toward the humerus, forming the posterior axillary fold with teres major, which lies superior to it along the lateral border of the scapula. Deep to these broad sheets, the erector spinae columns run longitudinally on either side of the spinous processes, hugging the thoracolumbar fascia and tracking from the sacral region toward the cervical spine. Fiber direction is explicit. This posterior perspective matters when you need to teach layered dissection logic and the relationship between scapulothoracic motion and glenohumeral mechanics: trapezius and deltoid define the superficial landmarks, but the deeper paraspinal mass explains extension and segmental stabilization across the vertebral joints. Rotator cuff-relevant territory is also present, with infraspinatus occupying the infraspinous fossa and inserting on the greater tubercle, while teres major heads toward the medial lip of the intertubercular sulcus, a frequent point of confusion with teres minor during exam prep and operative planning. Pain patterns track these layers. So do approaches. Use this asset for gross anatomy lab guides, physiotherapy teaching on posture and scapular dyskinesis, and orthopedic or sports medicine publishing that needs clean posterior shoulder and back muscle relationships without skin distraction. Anatomical accuracy verified by SciePro's Medical Advisory Board.