[Sabio]

Here's a nice diagram from Wikimedia Commons which illustrates the various types of brain herniations

The red collection is an example of any space occupying lesion that would result into herniations

The Four Types Illustrated are:

1. Subfalcine herniation, just above the corpus callosum and just below the falx cerebri where the cingulate gyrus press against the other side.
2. Midbrain herniates caudally.
3. Transtentorial (uncal) herniation where the uncus and the hippocampal gyrus herniates through the tentorial notch pressing against the brainstem. See this post for details
4. Tonsillar herniation, where the cerebellar tonsils herniate through the foramen magnum pressing against the medulla.