In Plain English
The back is a group of muscles spanning the rear of your torso, extending from the neck and shoulders down to the pelvis and attaching to the spine, ribs, shoulder blades, and upper arms. Together, these muscles pull your arms toward your body, move and stabilize your shoulder blades, support your spine, and create much of the thickness and width seen from behind.
Technical Definition
The back comprises several major muscle groups, including the latissimus dorsi, trapezius, rhomboids, teres major, rear deltoids, and spinal erectors, along with numerous deeper stabilizing muscles. These structures originate across the cervical, thoracic, and lumbar spine, ribs, pelvis, and scapula before inserting onto the humerus, scapula, and vertebral column. Collectively, they produce shoulder extension, shoulder adduction, horizontal abduction, scapular retraction, depression, elevation, upward rotation, spinal extension, and spinal stabilization while maintaining efficient force transfer between the upper limbs and trunk.























