The meninges are three layers of connective tissue that surround both the brain and spinal cord to form a complete enclosure (Fig. 6-3) . The outermost of these membranes, the dura mater, is the thickest and toughest of the meninges.he meninges are three layers of connective tissue that surround both the brain and spinal cord to form a complete enclosure (Fig. 6-3) . The outermost of these membranes, the dura mater, is the thickest and toughest of the meninges.
These are generally made of wood, steel, or concrete. While concrete is the most durable, it is also the most expensive and the most difficult to install. Steel ramps are more durable than wooden ramps, though they tend to be heavier, more expensive, and heat up in the sun. Wooden ramps are the most aesthetically pleasing, but need to be weatherproofed and treated in order to last. Depending on the type of wood and other specifications, a permanent wheelchair ramp used to reach a height of 30 inches (30 feet long) can cost between $3,500 and $8,000, or between $100 and $250 per linear foot.
Most portable ramps are made of aluminum and are easy to move and store whenever you need. The price of your portable wheelchair ramp will heavily depend on its length, but more often than not, you can find a safe and reliable portable handicap ramp for less than $1,300. On the other hand, if you know you will need a ramp for a long period of time and donât want to bring your ramp inside and outside every time you need it, we highly recommend biting the bullet and installing a fixed handicap ramp.