[Microanatomical study of transcerebellomedullary fissure approach]

To study the anatomy of structures on the way to the fourth ventricle of cerebrum via transcerebellomedullary fissure approach.

Ten cadaveric heads fixed with formalin and with their arteries and veins perfused with color latex were dissected with nicrosurgical anatomical skills to observe the structure of tela choroida, fourth ventricle roof, rhomboid fossa, and posterior inferior cerebellar artery (PICA) and its branches.

Via the transcerebellomedullary fissure approach, any part of the rhomboid fossa can be reached by exposing and separating the tela choroida, inferior medullary velum, and nodule of vermis, and the dorsolateral part of pons and of medulla obligata can be reached by lateral recess.

The fourth ventricle of cerebrum and the lateral parts of brainstem can be reached via transcerebellomedullary fissure approach through normal anatomical spaces. The tonsilomedullary and telovelotonsillar segments of PICA are the most important vessels in the transcerebellomedullary fissure approach.