GROSS ANATOMY

Detailed explanation-1: -The deep back muscles, also called intrinsic or true back muscles, consist of four layers of muscles: superficial, intermediate, deep and deepest layers. These muscles lie on each side of the vertebral column, deep to the thoracolumbar fascia.

Detailed explanation-2: -The intrinsic or deep muscles are those muscles that fuse with the vertebral column. The second group is the superficial muscles, which help with shoulder and neck movements. The final group is the intermediate muscles, which help with the movement of the thoracic cage.

Detailed explanation-3: -Superficial extrinsic muscles of the back: trapezius, latissimus dorsi, rhomboid major, rhomboid minor, and levator scapulae. Intermediate extrinsic muscles of the back: serratus posterior superior and serratus posterior inferior muscles.