Wrappings Around Brain/Spinal Cord

In class this week i learned about the wrappings around the brain and spinal cord, also known as the Meninges. The outer most layer is called the Dura Mater, which is where the major blood vessels are. The dura mater is two layers thick around the brain and only one layer thick around the spinal cord. The space above the dura mater is called epidural space, and the space below is the sub-dural space. The outer layer to the skull is called the Periosteal and the inner layer is the Meningeal. Then the middle most layer has blood vessels but not as many as the dura mater. Part of the middle layer is the arachnoid mater that doesn't have any blood vessels, and its spider like. the second layer is called the sub-arachnoid space which is where the cerbrospinal fluid is located. Lastly, the inner most layer is called the Pia mater which is where the capillary networks are, also known as blood vessels. This is the tender area.
The layers of he Meninges are important to my everyday life in many ways. When my step father was hurt in Iraq he had to go threw six hours of brain surgery. Obviously they had to go threw all three layers to get to his brain and work on it. Then once he was back in the states they had to go back into his brain to fix a hole in his dura. When doing this they also found a cotton ball left in his head from the previous surgery. If they hadn't gone in to fix the hole in his dura, it would have caused a major infection, and probably would have caused him death. The layers around your brain could cause major problem to your health if something goes wrong. I have learned a lot about head injuries, so learning about the dura was something i already knew, but the other layers not so much.