Degenerated Discs
	Herniated Discs
	Strains and Sprains
	Facet Arthropathy
	Stenosis
	Myelopathy
	Spondylolysis
	Spondylolisthesis
	Failed Back Syndrome

Mechanical conditions, such as muscle strains, occur when an anatomical structure in the spine fails to maintain its normal structure and/or function as a result of wear and tear (e.g., degeneration or structural damage). Disc degeneration, disc herniation, strains, sprains, facet arthropathy, stenosis, myelopathy, spondylolisthesis, spondylolysis, and failed back syndrome are all examples of mechanical conditions that affect the adult spine.

Degenerated Discs
As part of the natural aging process, intervertebral discs lose their flexibility and shock absorbing characteristics. The ligaments that surround the discs (annulus fibrosis) become brittle and easier to tear. At the same time, the soft jelly-like center of the disc (nucleus pulposus) starts to dry out and shrink. Over time, these changes can cause the discs to lose their normal structure and/or function.

Herniated Discs
A disc herniation occurs when the inner core (nucleus pulposus) of the intervertebral disc bulges out through the outer layer of ligaments that surround the disc (annulus fibrosis). This tear in the annulus fibrosis causes pain in the back at the point of herniation. If the protruding disc presses on a spinal nerve, the pain may spread to the area of the body that is served by that nerve. The terms "slipped," "ruptured," "torn," and "bulging" are also commonly used to describe this condition.

Strains and Sprains
The muscle, tendons, and ligaments function together to handle the external forces the spine encounters during movements, such as bending forward or lifting. Sprains and strains are similar disorders affecting these different soft tissues in the spine. Sprains affect ligaments, whereas strains affect muscles and tendons. By definition, both terms mean something has been stretched beyond its normal capacity. Back muscles may be strained, for example, if they encounter an excessive external force that causes strands of the muscle to stretch or tear.

Facet Arthropathy
Facet arthropathy is an abnormality of the facet joints caused by degeneration or arthritis of these anatomical structures.

Stenosis
Stenosis is a condition caused by a gradual narrowing of the spinal canal, which results from degeneration of both the facet joints and the intervertebral discs. Bone spurs, called osteophytes, which develop because of the excessive load on the intervertebral disc, grow into the spinal canal. The facet joints also enlarge as they become arthritic, which contributes to a decrease in the space available for the nerve roots. The ligaments of the spinal column, especially the ligamentum flavum, become stiff, less flexible, and thicker with age, which also contributes to spinal stenosis. These changes narrow the spinal canal and may impinge and put pressure on the nerves roots and/or spinal cord.

Myelopathy
Myelopathy is a condition caused by compression of the spinal cord. It is most commonly caused by spinal stenosis, which is a progressive narrowing of the spinal canal. In a similar manner, in the later stages of spinal degeneration, bone spurs and arthritic changes can decrease the space available for the spinal cord within the spinal canal.

Spondylolisthesis
Spondylolisthesis is a condition that occurs when one vertebra slips forward on another. This slippage produces both a gradual deformity of the lower spine and narrowing of the vertebral canal. Spondylolisthesis can occur anywhere in the spine, but is most common in the lumbar, or lower, spine.

Spondylolysis
Spondylolysis is a condition caused by a stress fracture in a vertebra, most commonly in the pars intrarticularis - section of the lamina between the posterior projections of the vertebrae that form the facet joints (the articular processes).

Failed Back Syndrome
Failed Back Syndrome (FBS) is a collection of conditions, not a single condition, that emerge after back surgery or other treatments. A failed back may result, for example, from complications that arise from spinal surgery or the natural healing process that follows surgery. A joint, for example, may become inflamed because of a treatment that has altered the person's posture and body movement. Similarly, scarring from spinal surgery may cause spinal nerves to become irritated.

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