The term 'disc' refers to the protective cartilage in between the spinal bones (vertebrae). These circular discs cushion the vertebrae when running, jumping or when pressure is placed down through the spine. The discs are made from a tough outer casing which contains a soft gel substance inside. The discs are susceptible to disease and injury which can result in disc and back problems.
The main causes of disc problems are listed below.Degenerative disease
At a young age, the discs between the vertebrae are plump but with age they begin to soften as water content reduces. This results in the discs becoming thin and hard and growths known as bone spurs can develop around the disc. Some people develop these growths with no associated problems but for those who experience pain they have a condition called degenerative disc disease.Slipped disc
The term 'slipped disc' isn't entirely accurate as it suggests the cartilage has moved out of position and this is not the case. In medical terms, the problem is described as a 'ruptured disc' or 'herniated disc.
The discs are held in position by ligaments, muscles and the vertebrae. When a crack in the hard outer casing develops, the soft gel-like substance inside seeps out. What causes this crack to occur is not always clear but age is the most likely factor as the disc becomes less flexible and more prone to rupturing.
There are a number of factors which can place pressure on the spine which can cause a rupture in the disc. These include:
- bending over awkwardly
- lifting heavy objects
- sitting for prolonged periods
- being overweight
- sports that involve weight-bearing (e.g. weight-lifting)
- back injuries (e.g. from a fall or car accident)
A ruptured disc typically occurs in the lower back.Sciatica
The sciatic nerve runs from the spine, through the buttock and down the back of the leg. Whenever the body moves, the spinal cord has room to move up and down the spinal column however if a disc ruptures it can protrude into the spinal column and press against the cord and sciatic nerve. This restricts movement of the cord and causes pain through the lower back and leg.