Corpus: Cerebellopontine angle

The cerebellopontocerebellar angle, or CPA for short, is an anatomical niche between the brain stem and the cerebellum.

The cerebellopontine angle is located at the posterior base of the brain and is bordered by the cerebellar tonsils and the caudal edge of the pons or the medulla oblongata. The space located here is an extension of the subarachnoid space and forms the cisterna pontocerebellaris, which is filled with cerebrospinal fluid. The following structures, among others, pass through the cerebellopontine angle:

• facial nerve, intermedius nerve (together the 7th cranial nerve)
• vestibulocochlear nerve (8th cranial nerve)
• Arteria cerebelli inferior posterior (PICA)
• Arteria cerebelli inferior anterior (AICA)
• Cerebral veins that open into the superior petrosal sinus.

Pathological processes in the cerebellopontine angle produce a complex pattern of symptoms that some authors refer to as cerebellopontine angle syndrome. It includes, among other things, loss of the cranial nerves running here as well as increased intracranial pressure.

The cerebellopontine angle is a frequent localisation for acoustic neuromas. In addition to symptoms of loss of the vestibulocochlear nerve, peripheral facial nerve paralysis also occurs here.