Where it is
- It is one of four folds of dura mater that divide the skull cavity into incomplete compartments: the cerebrum lies above it (supratentorial) and the cerebellum below it (infratentorial). [1]
- It lies between the cerebellum and brainstem below and the occipital lobes of the cerebrum above. [2]
- Its free border is U-shaped and forms the tentorial notch (tentorial incisure), the opening through which the midbrain, the top part of the brainstem, passes. [1]
- It slopes upwards from where it is fixed to bone towards its free border, so it follows the shapes of the cerebrum and cerebellum that rest against it. [1]
What it does
- It splits the skull cavity into a part above it, which holds the cerebrum, and a part below it, which holds the cerebellum; anatomists name places by it as supratentorial or infratentorial. [1]
- The occipital lobes rest on it. [4]
- Folds like it form at the major boundaries of brain regions, such as the longitudinal fissure between the two hemispheres, where the dura separates, folds and turns inwards to make the divisions. [2]
Connections
- At the back it is fixed along the transverse ridges on the inner surface of the occipital bone, reaching the internal occipital protuberance; at the front, to the upper edge of the petrous part of the temporal bone on each side, reaching the posterior clinoid processes. [1]
- Each side of its free border runs on forward to attach at the anterior clinoid process, forming a ridge of dura on the roof of the cavernous sinus. [1]
- The back end of the falx cerebri, the dural sheet between the two hemispheres, joins the midline of its upper surface, and the straight sinus runs along that join. [1]
- Below it at the back hangs the cerebellar falx, a smaller vertical fold that partly separates the two cerebellar hemispheres. [2]
- Its nerve supply differs above and below: the dura above it gets small meningeal branches of the trigeminal nerve, the dura below it upper cervical nerves and the meningeal branch of the vagus nerve. [2]
Inside it
- Two layers of dura mater, which part along its fixed edge to enclose the transverse sinuses at the back and the superior petrosal sinuses at the front. [1]
Other names
- Also called the cerebellar tentorium; tentorium cerebelli is Latin for “tent of the cerebellum”. [1]
Size
- On this model the right half of the tentorium cerebelli (the only half the atlas ships) measures about 87 mm front to back, 33 mm top to bottom and 60 mm side to side (the box it fits in, not its volume). [3]