不同枕下入路中椎动脉V3段的显微解剖学研究

The microanatomy study of the V3 segment of the vertebral artery by different suboccipital approaches

目的通过对椎动脉V3段的显微解剖探讨其在不同枕下入路中的定位标志及保护策略。方法应用10具(20侧)由10%多聚甲醛固定的成人尸头标本,逐层解剖枕项部肌肉,定位枕下三角,清除椎动脉周围静脉丛,显露椎动脉V3段并进行观测。分别从枕下后正中入路、枕下乙状窦后入路和极外侧经颈静脉突入路重点观察椎动脉V3段的毗邻结构,测量各入路重要骨性标志与椎动脉V3段间的距离。结果椎动脉V3段被枕下三角的肌肉和椎动脉周围静脉丛包裹,其椎动脉沟段的长度为(19.7±2.7)mm,外径为(5.4±1.3)mm。枕下后正中入路中,寰椎后结节至V3段内侧缘的直线距离为(19.1±4.1)mm。枕下乙状窦后入路中,枕鳞水平部至V3段上缘的垂直距离为(8.7±2.6)mm,与髁窝至V3段上缘距离[(8.7±2.5)mm]相近。极外侧经颈静脉突入路中,颈静脉孔后缘至V3段外侧缘的直线距离为(10.4±1.7)mm。结论熟悉椎动脉V3段的显微解剖及其在不同枕下入路中与周围定位标志间的距离,可为术中识别椎动脉V3段提供参考,降低椎动脉的损伤风险,提高枕下区手术的安全性。

Objective To explore the anatomical landmarks of the V3 segment of the vertebral artery and the preservation strategies in the suboccipital approach.Methods Ten adult cadaveric head specimens(20 sides)were fixed with 10%formaldehyde.The occipital muscles were dissected layer by layer from superficial to deep,the suboccipital triangle was located,and the venous plexus around the vertebral artery was removed to expose and observe the V3 segment of the vertebral artery.Then,the structures adjacent to the V3 segment of the vertebral artery were observed from the axial direction via the posterior suboccipital midline approach,the suboccipital retrosigmoid approach,and the extreme-lateral transjugular process approach.The distance between key bony landmarks of each approach and the vertebral artery was measured,respectively.Results The V3 segment of the vertebral artery was wrapped by the muscles of the suboccipital triangle and the venous plexus around the vertebral artery.The length of the V3 segment was 19.7±2.7 mm,with an outer diameter of 5.4±1.3 mm.The distance from the posterior tubercle of the atlas to the medial edge of the V3 segment was 19.1±4.1 mm in the posterior suboccipital midline approach.The vertical distance from the horizontal part of the occipital scale to the upper edge of the V3 segment was 8.7±2.6 mm,which was similar to that from the condylar fossa to the upper edge of the V3 segment(8.7±2.5 mm)in the suboccipital retrosigmoid approach.The straight-line distance from the posterior edge of the jugular foramen to the lateral edge of the V3 segment was 10.4±1.7 mm in the extreme-lateral transjugular process approach.Conclusion Familiarity with the microanatomy of the vertebral artery V3 segment and its distances from surrounding landmarks can provide reference for identifying the vertebral artery V3 segment during surgery,reducing the risk of injury to the vertebral artery,and improving the safety of surgery in the occipital region.