Posture refers to "the carriage of the body as a whole, the attitude of the body, or the position of the limbs (i.e. the arms and legs)” (Webster’s New World Medical Dictionary).
The word “posture” comes from the Latin verb “ponere” which means “to put or place”.
In medicine and occupations concerned with physical fitness, the concept of good posture is referred to as a "neutral spine." In this context, proper posture or "neutral spine”, is the proper alignment of the body between postural extremes. In its natural alignment, the spine is not straight. It has curves in the upper (thoracic) and lower (lumbar) regions. There is a slight forward curve in the lower lumbar region (lordosis), a slight backward curve in the upper thoracic region (kyphosis) and a slight extension in the tiny cervical vertebra at the top of the spine. In addition, the ears, shoulders, hips, knees and ankles are aligned as if a plumb line were running from the ears down through the torso into the legs and the feet. In neutral posture, the body is able to function in its strongest, most balanced position. Stress to the joints, muscles, vertebrae and tissue is, therefore, minimized.
In contrast, a non-neutral spine leads to improper posture, which places increased stress on your back and causes discomfort, and potentially damage. A non-neutral spine develops as the result of a person's lifestyle. For example, people who sit for long hours as part of their job are susceptible to a number of misalignments and some medical conditions.
A "neutral spine" is ideally maintained while sitting, standing or sleeping.
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