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.
For example, it will take a carpenter approximately 8 hours to build a permanent ramp to your home if you have a steep staircase, for a total of $560 in labor. A plumber to swap out your faucet handles for more accessible versions will cost around $50.