An abnormality of the fossa cranii posterior (the posterior fossa), which is made up primarily of the occipital bone and which surrounds to the foramen magnum.
Comment:
The floor of the cranial cavity is divided into three distinct depressions called the anterior, middle, and posterior cranial fossa. The posterior cranial fossa, the most posterior and deep of the three cranial fossae, accommodates the brainstem and cerebellum. Abnormalities of the posterier cranial fossa can be demonstrated by cerebral magnetic resonance imaging or computer tomography.
Synonyms:
exact_synonym:
Abnormality of the posterior cranial fossa; Abnormality of the posterior fossa; Posterior fossa anomaly