„omega shape“ anomaly of the tympanic segment of the facial nerve – a case report

Dehiscence of the bony canal of the facial nerve is relatively common in the human adult. The highest incidence occurs in the tympanic segment, near the region of the oval window. However, extreme dehiscence and protrusion of the facial nerve are rare. We present a case of a 34-year-old man suffering intermittent left-sided middle ear discharge for several years. During the operation, we found the trunk of the facial nerve which looked like Greek alphabet letter “omega”. It protruded from the fallopian canal within the middle ear space between the first and second genu. The mucosa which covered the whole protruded facial nerve seemed healthy. The medial part of the cavum tympani was not affected. In this report, we described an extreme protrudion of the facial nerve inside the space of the cavum tympani. The dehiscence of the Fallopian canal was not associated with inflammation and bone resoption.