The 4 different stages of spinal degeneration explains the progressive nature of the accelerated wear and tear associated with spinal subluxations…
THE INTERVERTEBRAL DISC
Many lower back problems especially those correlating with pain down the back of the leg are caused by intervertebral disc problems. The disc is a pad, hydraulic in nature that sits between the spinal vertebras. The disc allows motion and acts as a shock absorber.
THE NORMAL DISC
The disc is made of two components:
1.    The annulus fibrosis which is a fibrous ring on the outer rim of the disc.
2.    The nucleus pulposus which is a jelly like substance with a high fluid content that sits inside the annulus fibrosis and gives the disc its hydraulic action.

STAGE 1: SUBLUXATIONS AND THE DISC
A Subluxation is a slight vertebral misalignment that may lead to a mechanical fixation that disturbs the normal range of motion of that spinal segment. This may lead to interference to the normal function of surrounding nerves and if not corrected can slowly result in disc degeneration with or without symptoms.

STAGE 2: THE DEGENERATIVE INTERVERTEBRAL DISC
The degenerative disc is a condition that develops over a long period of time as a result of an injury causing damage to the spine and abnormal spinal motion. The associated muscle spasm and joint fixations leads to a locking up of the vertebras and an inhibition of normal motion to that spinal segment. The disc relies on motion for fluid exchange and healthy function as nutrients are carried in and waste products carried out.
When that occurs the disc begins to dehydrate, thins out and loses its shock absorbing ability. The constant stress on the disc may also weaken the outer wall producing a protrusion of the disc.
 STAGE 3: OSTEOARTHRITIS
Osteoarthritis is the wear and tear type of arthritic conditions. Due to the constant and often pain free degeneration of the disc and surrounding joints, spurs and calcification of ligaments occurs and causes further restriction of movement and pain. The spurs may pinch pain sensitive nerves exiting the spine and the disc thinning brings the vertebras closer together narrowing the nerve channels.
Long term this condition is progressive and leads to irreversible damage which may cause the spine to fuse together. Treatment in the early stages of its development may slow down its progress by improving movement and increasing fluid exchange to the disc.

STAGE 4A: PROTRUDED INTERVERTEBRAL DISC
This condition occurs when the annulus fibrosis of the disc becomes weak and the disc protrudes or bulges out, usually into the nerve area. This causes severe back or neck pain with associated pain referral.
Disc protrusion in its early development although painful still responds well to conservative chiropractic treatment. Restoration of the structural and mechanical faults in the spine and strengthening surrounding muscles helps the disc regain its integrity.
Prevention of future recurrent episodes of disc protrusion and proper spinal maintenance is the key to a healthy disc as every episode may lead to tearing of the discs outer fibres which further weakens the disc and can ultimately result in a much more serious disc condition.
STAGE 4B: RUPTURED OR HERNIATED INTERVERTEBRAL DISC
In this final stage of development the outer layer of the disc is so weakened that the tear in the fibres of the annulus fibrosis is severe enough to allow the jelly-like substance in the centre of the disc to ooze out and encroach on surrounding nerves.
Disc herniation is not common as it normally requires a severe injury or repeated disc protrusions. However, getting the jelly–like disc material back inside the disc once it’s outer rim has ruptured is like getting toothpaste back inside the tube after it has been squeezed out. That is why once the disc is ruptured surgery is required.
The key factor in any of the disc conditions mentioned above is that once the disc heals and returns to normal a preventative spinal care program needs to be implemented so that the spine receives regular chiropractic care to help maintain future health and prevent further episodes from recurring. 

(Did you know that your spinal discs make up 1/3 of the height of your spine and in the morning when your spine is rested and your discs are hydrated you are about an inch or so taller than at night).