posterior fossa的用法和樣例：
例句
- Gliomas in children, therefore, are most common in the posterior fossa.
因此，兒童膠質瘤在顱后窩最常見。 - The irregular posterior fossa mass that is seen here near the midline of the cerebellum and extending into the fourth ventricle above the brainstem is a medulloblastoma.
不規則顱后窩腫塊即髓母細胞瘤，在小腦中線附近並且延伸至腦幹之上的第四腦室。
