Three-dimensional microsurgical anatomy of cerebellar peduncles.

The microsurgical anatomy of cerebellar peduncles and their relationships with neighbouring fasciculi were investigated by using a fibre dissection technique. As the dissection progressed, photographs of each progressive layer were obtained and stereoscopic images were created using the 3D anaglyphic method. These findings provided the anatomical basis for a conceptual division of cerebellar peduncles into segments. The middle cerebellar peduncle (MCP) was divided into two segments: cisternal and intracerebellar segments. The inferior cerebellar peduncle (ICP) was divided into three segments: cisternal, ventricular and intracerebellar segments. The superior cerebellar peduncle (SCP) was divided into three segments: intracerebellar, intermediate and intrategmental segments. The fibre dissection technique disclosed a constant course of peduncular fibres inside the white core of the cerebellum. The pontocerebellar fibres of the MCP pass over and laterally to the bundles of the ICP and SCP. The centripetal fibres of the ICP wrap around the radiation of the SCP and the dentate nucleus, directed towards the cortex of the vermis. The centrifugal bundle of the SCP ascends towards the mesencephalon where it sinks passing below the fibres the lateral lemniscus. The knowledge gained by studying the intrinsic anatomy of the cerebellum is useful to accomplish appropriate surgical planning and, ultimately, to understand the repercussions of surgical procedures on the white matter tracts in this region.