Microsurgical Anatomy And Lateral Operative Approach Of Petroclival Region

Part Ⅰ Microanatomy of petrous bone　　Objective: To provide anatomical basis for clinical application of petrous bone through studying the bone structures and the relationship between important structure of petrous bone, finding osseous location landmarks of lateral operative approach and defining the drilling regions of petrous bone in different directions 　　Methods: Observing and drilling of petrous bone and determining the distance between corresponding structures in 15 cadaveric adult heads on petrous bone and the surrounding structures which were performed from anterior lateral and posterior lateral directions by operative opproach Results: ①The foramen spinosum is situated medial to the root of zygoma 22 76(20 00～23 96)mm and lateral anterior to carotid canal 4 20(2 90～6 00)mm, and the greater superficial petrosal nerve groove can be located by it ②the greater superficial petrosal nerve groove is situated posterior to foramen spinosum about 4 80(3 96～7 40)mm, through which the intrapetrous carotid artery, cochlear and geniculate ganglion can be found out; ③ The petrosigmoid intersection which is the intersecting point of superior petrosal sinus and sigmoid sinus is the first point that will be met in drilling posterior petrous bone and it's location is unchanged ④ The fissure for endolymphatic sac is the situation that vestibular agueduct opens inferiorly to endolymphatic sac and it's location is unchanged ⑤The　facial nerve is divided into 5 segments: intracranial segment(12 32mm), internal acoustic meatus segment(9 18mm), labyrinthine segment(5 14mm), tympantic segment(11 82mm) and mostoid segment(17 90mm) ⑥ The distance between genu of petrous carotid and Cochlea is 2 65mm The horizontal segment of petrous carotid is parallel with the greater superficial petrosal nerve ⑦The limination of drilling anterior petrous bone is superior to the superior edge of petrous bone, inferior to petrous carotid, inferior petrosal sinus, Cochlea and internal acoustic meatus, medial to Dorello canal, lateral to superior semicircular canal ⑧ A triangle can be used to stand for the drilling range of posterior petrous bone: the tip of triangle is PS, the base is the linking line of posterior lip of jugular foramen and the intersection that it's extension line through the posterior lip of internal acoustic meatus that intersects the edge of petrous bone In this triangle, the important structures are posterior semicircular canal, vestibular aqueduct and commn crus and the bone drilled depth are 4 52mm, 2 14mm, 1 88mm and 2 36mm in order in posterior petrous 　　Conclutions: The foramen spinosum and the greater superficial petrosal nerve are important landmarks in drilling anterior petrous bone The petrosigmoid intersection and the fissure for endolymphatic sac are important landmarks in drilling posterior petrous bone To master the microanatomy of petrous bone is an important precondition of lateral approach operation to petroclival region Part Ⅱ Microanatomy of petroclival regionObjective: To provide anatomical basis for studing operative approach of petroclival region through studying the relationship between nerve and artery and their and perforating arteries' behaviores of distribution and course in petroclival region Methods: To study the behavior of distribution and course of nerves and arteries, the anatomical relationship of the arteries to nerves and adjacent structures in 15 cadaveric adult heads whose arteries had been injecteded with colored silicone and the cerbral had been resected through different directions in microscop Results: Petroclival region can be divided into 3 spaces according to the intradural structures: the superior petroclival space, the middle petroclival space and the inferior petroclival space ① The superior petroclival space: The distance is 5 38(4 16～6 86)mm from the point that Ⅳ enter into the edge of tentorium cerebelli to Ⅲ The course of posterior cerebral artery (PCA) can be divided 3 segments:anterior mesencephalic...