Thoracic Mobility Exercise.
Quadruped position, hands under the shoulders & knees under the hips, spine neutral.
Position one hand on back of your head, or upper back. Do not press / pull on the head.
Bring your elbow toward the opposite knee, your gaze should follow. Keep the other arm straight, and go as far as comfortable without losing your position.
Reverse the motion, rotating your shoulder and head upward as far as possible. Pushing through the floor with your posted hand.
Maintain neutral position with your hips and lumbar spine.
Return to the start. Repeat for repetitions and then switch sides.