Meningiomas are named according to their location (Fig 1) and cause various symptoms: 1  Convexity meningiomas: grow on the surface of the brain. They may not produce symptoms until they reach a large size. 2  Falx and parasagittal meningiomas: grow from the dura fold that runs between the left and right sides of the brain.
Tectum | Tegmentum | See also. The midbrain, or mesencephalon is made up of two main structures and surrounds the cerebral aqueduct.he midbrain, or mesencephalon is made up of two main structures and surrounds the cerebral aqueduct.
It is made up of two layers-the epidermal and dermal layers. The epidermal layer is the thinnest of the layers and is made up of its own set of thinner layers. The outermost layer is composed of keratin (a fiber protein) cells. These cells combine with a thin layer of oil to create a water-proof layer.