The<unk>  (from Latin<unk> , "worm") is located in the medial, cortico-nuclear zone of the cerebellum, which is in the posterior fossa of the cranium. The primary fissure in the<unk>  curves ventrolaterally to the superior surface of the cerebellum, dividing it into anterior and posterior lobes. Functionally, the<unk>  is associated with bodily posture and locomotion. The<unk>  is included within the spinocerebellum and receives somatic sensory input from the head and proximal body parts via ascending spinal pathways. The cerebellum develops in a rostro-caudal manner, with rostral regions in the midline giving rise to the<unk> , and caudal regions developing into the<unk>  hemispheres. By 4 months of prenatal development, the<unk>  becomes fully foliated, while development of the hemispheres lags by 30–60 days. Postnatally, proliferation and organization of the cellular components of the cerebellum continues, with completion of the foliation pattern by 7 months of life and final migration, proliferation, and arborization of<unk>  neurons by 20 months. Inspection of the posterior fossa is a common feature of prenatal ultrasound and is used primarily to determine whether excess fluid or malformations of the cerebellum exist. Anomalies of the<unk>  are diagnosed in this manner and include phenotypes consistent with Dandy–Walker malformation, rhombencephalosynapsis, displaying no<unk>  with fusion of the<unk>  hemispheres, pontocerebellar hypoplasia, or stunted growth of the cerebellum, and neoplasms. In neonates, hypoxic injury to the cerebellum is fairly common, resulting in neuronal loss and gliosis. Symptoms of these disorders range from mild loss of fine motor control to severe mental retardation and death. Karyotyping has shown that most pathologies associated with the<unk>  are inherited though an autosomal recessive pattern, with most known mutations occurring on the X chromosome. The<unk>  is intimately associated with all regions of the<unk>  cortex, which can be divided into three functional parts, each having distinct connections with the brain and spinal cord. These regions are the vestibulocerebellum, which is responsible primarily for the control of eye movements; the spinocerebellum, involved in fine tune body and limb movement; and the cerebrocerebellum, which is associated with planning, initiation and timing of movements.
Cerebellar vermis
Midbrain reticular formation
Barrel cortex
Fusiform body area
Periaqueductal gray
Middle cerebellar peduncle
Hindbrain
Piriform cortex