The facial nerve coursing across the oval window area.

A case of unilateral conductive deafness since birth is described. At exploration of the middle ear, the facial nerve was found to have an anomalous course across the oval window region, the stapedial crura ending on the uncovered facial nerve. This case is believed to represent the 9th case to be recorded. This anomaly may be due to failure of union between the branchial part and otic capsule part of the stapes, in combination with a defective development of the laterohyale resulting in a partially absent facial canal.