蚓部为小脑左右半球链接的部份，中间有神经元链接两个半球的息作交流。上方有一硬脑膜结构，小脑镰将小脑左右半球分隔。

The cerebellar vermis (Latin for worm) is located in the medial, cortico-nuclear zone of the cerebellum, residing in the posterior fossa of the cranium. The primary fissure in the vermis curves ventrolaterally to the superior surface of the cerebellum, dividing it into anterior and posterior lobes. Functionally, the vermis is associated with bodily posture and locomotion. The vermis is included within the spinocerebellum and receives somatic sensory input from the head and proximal body parts via ascending spinal pathways.