Anatomic Investigation of Intratemporal Facial Nerve Canal and Its Clinical Significance

Objective: To investigate the microdissection of intratemporal facial nerve canal and its adjacent structures,and to provide anatomic data for clinical surgery.Methods: The intratemporal facial nerve canal and its adjacent structures were observed in 15 adult wet skull specimens(30 temporal bones) by simulating traditional clinical operation via transmastoid and middle cranial fossa approaches.Results: The facial nerve canal included labyrinthine,tympanic,and mastoid segments.The length of labyrinthine segment was 2.67±0.23 mm in the left,and 2.60±0.23 mm in the right.Its diameter was 1.46±0.60 mm in the left,and 1.50±0.56 mm in the right.The length of tympanic segment was 10.63±0.58 mm in the left and 10.58±0.75 mm in the right.Its diameter was 1.93±0.09 mm in the left,and 1.94±0.11 mm in the right.The length of mastoid segments was 14.37±(0.93 mm) in the left and 14.31±0.97 mm in the right.Its diameter was 2.37±0.12 mm in the left and 2.37±0.10 mm in the right.The angle between labyrinthine and tympanic segments was 76.6°±3.13°(left) and 76.5°±2.75°(right),respectively.While the angle between tympanic and mastoid segments was 113.1°±3.94°(left) and 112.4°±2.77°(right),respectively.Conclusion: Horizontal semicircular canal,digastric ridge,facial recess,cochleariform process,tarin foramen,arcuate eminence,and foramen spinosum are important signs of the facial nerve canal.The knowledge of the microdissection of intratemporal facial nerve canal and its adjacent structures would make the surgery smoothly.