Latissimus Dorsi Muscle

The latissimus dorsi muscle in the back is attached to the pelvic girdle and vertebral column and the movable end is close to the midline of the humerus (upper arm bone). Usually, it functions to pull the arm toward the back as in rowing a boat or swimming, but during chinning exercises, the end attached to the humerus becomes the immovable end of the muscle, and the end attached to the pelvis and vertebral column moves.