Lordosis

The term lordosis refers to the normal inward lordotic curvature of the lumbar and cervical regions of the spine. Excessive curvature of the lower back is known as lumbar hyperlordosis, commonly called sway back, hollow back or saddle back (after a similar condition that affects some horses). A major feature of lumbar hyperlordosis is a forward pelvic tilt, resulting in the pelvis resting on top of the thighs. Curvature in the opposite convex direction, in the thoracic and sacral regions is termed kyphotic. When this curvature is excessive it is called kyphosis or hyperkyphosis.

Cause

Normal lordotic curvatures, also known as secondary curvatures, results in a difference in the thickness between the front and back parts of the intervertebral disc. Lordosis may also increase at puberty sometimes not becoming evident until the early or mid-20s. Imbalances in muscle strength and length are also a cause, such as weak hamstrings, or tight hip flexors (psoas).

Other health conditions and disorders can cause lordosis. Achondroplasia (a disorder where bones grow abnormally which can result in short stature as in dwarfism), Spondylolisthesis (a condition in which vertebrae slip forward) and osteoporosis (the most common bone disease in which bone density is lost resulting in bone weakness and increased likelihood of fracture) are some of the most common causes of lordosis. Other causes include obesity, kyphosis (spine curvature disorder in which the thoracic curvature is abnormally rounded), discitits (an inflammation of the intervertebral disc space caused by infection) and benign juvenile lordosis.