OBJECTIVE: To further understand the traverse connections of nerve components in the vestibular sensory epithelium. METHODS: The nerve innervations in the vestibular sensory epithelia and infraepithelia of ten healthy guinea pigs (16 ears) were observed by transmission electron microscopy. RESULTS: Type I sensory cells were intricately connected with type II cells. Afferent and efferent fibers as well as their endings had also complicated connections with nerve trunks and branches. The traverse connections appeared among nerve components in the vestibular sensory epithelium were extremely complicated, forming multilevel connections. They stemmed from and end in the crista ampullaris and the maculae. CONCLUSION: These complicated and multilevel connections are the basis of nerve activity in the vestibular apparatus.