目的　观察面神经鼓索发出的位置和类型，为面神经减压手术和其它中耳乳突手术提供解剖学资料。 方法　2005年4月~2009年10月在我科接受单侧面神经减压术的216名成年汉族周围性面瘫患者，在手术显微镜下，观察分析鼓索发出的位置和类型。 结果　鼓索以单根的形式由面神经干发出占69.0%（149例）。以双根的形式发出，占19.4%（42例）。以3根的形式发出，占3.2%（7例），鼓索的多个根最终都在面隐窝下方汇合成1根，进入鼓室。由于手术入路的关系，18例未见鼓索的发出点，占8.3%。单根鼓索按发出的部位：由茎乳孔区的锥形筋膜分出占55.0%（82例），由乳突段面神经干分出占43.0%（64例），由面神经锥段分出者占2%（3例）。 结论　鼓索由面神经乳突段发出的只占29%。22.6%的鼓索存在多根现象，本调查还发现2%的鼓索由面神经锥段发出的异常现象，都应该引起医生的重视，避免在手术中误伤，出现医疗事故。

Objective　to study the location of chorda tympani, and provide relevant anatomical data for facial nerve decompression surgery and other mastoid surgery.　Methods　From April 2005 to October 2009, there were 216 adult Han nationality patients with peripheral facial paralysis receiving  facial nerve decompression, in the surgery, under NC4 surgical  microscope, the chorda tympani location and the type of issue were observed and analyzed.　Results　69.0%(149 cases) of chorda tympani nerve issues from the facial nerve in the form of a single root, and 19.4%(42cases) of chorda tympani nerve issues in the form of double roots, while 3.2%(7cases) of chorda tympani nerve has 3 roots, there is no pattern in 4 roots or more, all roots converge into a chorda tympani nerve on the top of the facial nerve recess and then go into the middle tympanum.  Due to our surgical approach, chorda tympani roots were not found in 18 cases(8.3%). Single chorda tympani nerve by the issuing site is divided into: from the cone-shaped fascia of stylomastoid foramen region in 82 cases, accounting for 55.0%, from the mastoid segment of the facial nerve in 64 cases, accounting for 43.0%, from the second genu of the facial nerve in 3 cases, accounting for 2%.　Conclusion　In adult Han population, the branch form of the chorda tympani nerve is more complex than that in our traditional knowledge. There is the phenomenon of multiple roots. 69% of the chorda tympanis have single root, while 22.6% have multi-roots phenomenon, only 29.6% of chorda tympani nerves issues from the mastoid segment of facial nerve. In addition, in this survey, we found that three cases of chorda tympani issued from the second genu of the facial nerve, these phenomena should arise the doctor's attention, so that we can avoid accidental injury to this malformation of chorda tympani during the surgery.