Lordosis

Lordosis is a term used to describe the direction of the curvature of the five lumbar and seven cervical vertebrae of the vertebral column. With reference to human anatomy, this curve can be said to have an arch with the apex pointing in the anterior direction. When referring to the anatomy of other mammals, the direction of the curve is termed ventral. Curvature in the opposite direction, that is, apex posteriorly (humans) or dorsally (mammals) is termed kyphosis.

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Lumbar and cervical vertebras have lordotic curvatures, also known as secondary curvatures (which are concave towards the back). Secondary curvatures of the vertebral column are caused mainly because of the difference of thickness between the anterior and posterior part of the intervertebral disc. Those curvatures start to appear during the fetal period, but don't become evident until lactation.

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Excessive lordotic curvature is also called hollow back, saddle back, and swayback. Loss of lordosis is sometimes seen with painful spinal conditions. If rigid, usually after spinal fusion surgery, it is known as flat-back.

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The familiar concave shape of the horse's back is, by extension, described as lordotic.

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Lordosis also refers to the position that some mammals (cats, mice, etc) display when they are ready to mate. The position receives its name from the way the spine curves when the animal is in the position.

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Lumbar: In anatomy, lumbar is an adjective that means of or pertaining to the abdominal segment of the torso, between the diaphragm and the sacrum (pelvis). The five verterbrae in the lumbar region are the largest and strongest in the spinal column. In most mammals, the lumbar region of the spine curves o...

Vertebral column: The vertebral column (backbone or spine) is a column of vertebrae situated in the dorsal aspect of the abdomen....

Kyphosis: The medical term kyphosis has several meanings....