Applied anatomy of petrous bone in operation approach of petroclival region

Objective:To provide anatomic basis for clinical application of petrous bone.Methods:A microanatomy study of petrous bone along with the structures around it was performed on fifteen cadaveric adult heads specimens from anterior,lateral,posterior direction by operation approach.Results:①Trigeminal nerve can be moved towards inferior and lateral by drilling the petrous apex;②Abducens nerve was the medial limit of drilling petrous bone; ③Facial nerve was divided into 5 segments: intracranial segment(12.32 mm),internal acoustic meatus segment(9.18 mm),labyrinthine segment(5.14 mm),tympanic segment(11.82 mm) and mastoid segment(17.90 mm);④The height of jugular bulb had great variation; ⑤The distance between genu of petrous carotid and cochlea was 2.65mm.The distance from genu of petrous carotid to cochlea was 2.65 mm.The horizontal segment of petrous cartoid was parallel with the greater petrosal nerve.Conclusions:①The greater petrosal nerve is an important landmark in drilling anterior petrous bone;②Petrosigmoid intersecion and fissure for endolymphatic sac are important landmarks in drilling lateral and posterior petrous bone.