Neutral spine

A neutral spine or good posture refers to the "three natural curves [that] are present in a healthy spine." Looking directly at the front or back of the body, the 33 vertebrae in the spinal column should appear completely vertical. From a side view, the cervical (neck) region of the spine (C1-C7) is bent inward, the thoracic (upper back) region (T1-T12) bends outward, and the lumbar (lower back) region (L1-L5) bends inward. The sacrum (tailbone area) (S1-S5 fused) and coccyx (on average 4 fused) rest between the pelvic bones. A neutral pelvis indicates the anterior superior iliac spines and pubic symphysis fall in the same vertical line.

Posture and natural curvatures

The word posture comes from the Latin verb ponere, which means "to put or place." The general concept of human posture refers to the "carriage of the body as a whole, the attitude of the body, or the position of the limbs (the arms and legs)."

Webster's New World Medical Dictionary defines neutral posture as the stance that is attained "when the joints are not bent and the spine is aligned and not twisted. Neutral posture has given rise to the idea of achieving “ideal posture.” Ideal posture indicates proper alignment of the body’s segments such that the least amount of energy is required to maintain a desired position. The benefit of achieving this ideal position would be that the least amount of stress is placed on the body’s tissues. In this position, a person is able to completely and optimally attain balance and proportion of his or her body mass and framework, based on his or her physical limitations. Good posture optimizes breathing and affects the circulation of bodily fluids.