Buddy has a Slipped Disc.....What does this mean?

Got up this morning and as always get ready to take Buddy out for a walk and go potty. He usually beats me to the door. Not this morning. I had to wake him up in his bed. He could not raise his head. I got him to stand up on his own but his head was straight down with his nose straight into the carpet. I tried to raise his head and he cried. So sad. Scooped him up and off to the Vet. We were waiting in the car when the nurses drove in. We got into the room and Dr. Austin came right in. He looked at him and in 1 minute tops he diagnosed Buddy with a Slipped Disc. He calmed me down and said it was very common and always happens with the same symtoms. So treatment consists of an injection of Dexasone, Laser therapy and 10mg of Prednisone twice a day for 5 days, strict rest for at least 4 weeks all to reduce inflammation and pain .

Why does a disc 'slip'?
A slipped disc can happen in 2 ways:

1. Rupture of a healthy disc can be caused by trauma (such as a road traffic accident, or a fall from height) with tearing of the annulus fibrosus.
2. Degeneration of the disc is a result of a premature ageing process. This causes progressive thickening of the dorsal part of the annulus fibrosus which presses up on the spinal cord (disc protrusion). Disc degeneration is more common in the regions of the spine which are particularly exposed to physical stress (the lower neck, mid-back and lower-back).