Microanatomic study on the approach to jugular foramen area via transcondylar-jugular process

Objective:To study the relationship between the jugular foramen and its adjacent structures,measure occipital condyle and paracondyle structures,to correctly direct operative approach.Methods:Observation and measurement of jugular formaen,occipital condyles,jugular process,hypoglossal canal and paracondylar tissues were carried out on 10 cadaveric head and 15 dry skull bases by using microsurgical anatomic skills. Results:Different ratio relations to atlantooccipital joint interfaces were decided for condylar extension drilled.Jugular process situated in the posteriolateral to condyle,interior to styloid and digastric groove,posterior to superiorlateral loop of vertebral artery, and consisted in posterior wall of jugular foramen.It companied with carotid canal and hypoglossal canal outside hole,and formed triangle that posterior groups nerve and jugular buld existed in.Conclusions: It′s advanced approach compard with suboccipital extreme approach.The exposure of jugular foramen posterior wall by drilling away partial condyle and jugular process,for avoiding facial nerve transposition and petrosal bone being drilled.