A herniated disk, sometimes (incorrectly) called a slipped disk, is a common cause of severe back pain and sciatica. A disk in the lumbar area becomes herniated when it ruptures or thins out, and degenerates to the point that the gel within the disk (the nucleus pulposus) pushes outward.
The ceiling fan's downrod must be long enough for the fan's blades to clear the ceiling. A fan with a 12-inch downrod works for a vaulted ceiling with a one-quarter-to one-third-inch pitch. An 18-inch downrod is sufficient for a pitch that is five-twelfths to one-half inch.
How long of a down rod should I choose? The down rod, commonly referred to as the pole or pipe of a ceiling fan, is very important for both proper circulation, and overall room aesthetics. In addition, the down rod has a direct effect on the amount of air you feel from your ceiling fan. Proper circulation helps ensure the maximum efficiency from your ceiling fan. Your fan blades need to have at least a 3 inch clearance on either side and an 8 inch clearance between the blades and the ceiling.