Anatomy of the skull

The skull is a hard, bony box protecting the brain. It fits neatly around the brain, with the brain sitting inside, floating in cerebrospinal fluid.

There are a number of bony ridges that are on the inside of the skull that fit into gaps in the brain. These ridges can cause damage to brain tissue in the event of a TBI. This damage can commonly include lacerations or contusions around the frontal/ temporal lobes and contra-coup damage in the region of the occipital lobe.

Blood vessels line the inside of the skull, and there is a hole (the foramen magnum) at the base of the skull where the brain becomes the spinal cord.

Anatomy of the brain

The brain is made up of two different types of tissue:

• Grey matter: which is groups of nerve cells that form layers of soft grey tissue
• White matter: which is long fibres that connect different groups of cells and have the consistency of al dente spaghetti or jelly

The brain has a left and right hemisphere. Each hemisphere controls the opposite side of body. The left side also usually controls understanding and production of speech. Each hemisphere is divided into 4 lobes - frontal, temporal, parietal, occipital. Different lobes, and different areas within each lobe, control different functions.

At the base of the brain, just above where it turns into the spinal cord is an area called the brain stem. The brain stem controls our vital functions such as breathing. If the brain stem is damaged it can be extremely life threatening.

Many of the things we do depend on several functions, which means several of these areas must work together. For example, in order to follow the direction "put your socks on" you need to use the following areas:

• the area for understanding language, in order to understand the direction
• the area for spatial orientation, to be able to find your sock
• the area for controlling limb movements, in order to put your sock on
• and the area for planning in order to be able to plan these steps and execute them in the correct order

To allow the different areas of the brain to work together, the brain has networks of nerve fibers that connect the areas together. There are also nerve fibers that connect the brain to the rest of the body, allowing it to control the activities of the person. If either the area that controls a function, or the nerve fibers that connects that area to the rest of the brain or to the body are damaged, a person will have difficulty performing that function.

People often focus on exercise or physiotherapy for an arm or leg that doesn't work, and think the problems is with the limb, when it may be the part of the brain that controls that limb, or the nerve fibers that connect the brain to the limb that have been damaged.