A collection of the best exercises for your middle back or latissimus muscles. The middle back consists of the latissimus dorsi, a large fan-shaped muscle that arises from the lower half of the spinal column and the rear ridge of the pelvic bone (posterior iliac crest). From its large origin, the latissimus converges into a bandlike tendon that attaches to the upper humerus (next to the tendon of the pectoralis major). When the latissimus dorsi contracts, movement takes place at the shoulder joint. The latissimus dorsi pulls the upper arm downward and backward (shoulder extension); hence this muscle is targeted by pulldowns, pull-ups, and rows. The latissimus also pulls the arm in against the side of body (adduction).