目的　探讨经脊柱颈段椎间盘入路椎管内减压的相关解剖。  方法　取18具正常成人颈段脊柱防腐标本，通过不同断层，观察硬脊膜、后纵韧带与硬膜外前隙的毗邻关系和结构特点；测量椎间盘平面的硬脊膜厚度、后纵韧带宽度、椎体矢状径长度。  结果　颈段后纵韧带分为深、浅层，两层在中线两侧4～5 mm处分开，浅层与硬脊膜形成潜在的硬膜外前隙，该隙内有Hofmann's韧带连于硬脊膜与后纵韧带之间。深、浅层在硬脊膜前外侧形成一梭形腔隙－后纵韧带间隙； 椎体后面矢状正中线到两侧后纵韧带间隙外侧角的距离约为10 mm。  结论　根据后纵韧带的宽度和毗邻关系，颈椎前路手术经椎间盘达后纵韧带，逐渐由外进入后纵韧带间隙减压,可减少硬膜囊、脊髓或神经根的损伤。

Objective　To discuss the safety range of spinal canal decompression via intervertebral disc approach.　Methods　Cervical vertebra specimens from 18 embalmed adult cadavers were dissected for observing anatomic features of the dura mater, posterior longitudinal ligament and anterior epidural space. The thickness of dura mater, the width of posterior longitudinal ligament and the sagittal diameter of vertebral body at the intervertebral disc level were measured and analyzed.　Results　The posterior longitudinal ligament composed of deep and superficial layers, which separated from each other leaving the median line about 4 to 5 mm.  The anterior epidural space was composed of the superficial layer of posterior longitudinal ligament and dural mater. We also identified Hofmann ligament anterior to the dura mater, attaching the dura to the posterior longitudinal ligament. Deep and superficial layers formed a fusiform space, which was named as the posterior longitudinal ligament space. The distance from the middle of posterior margin of intervertebral disc to the lateral angle of each side of the space was about 10 mm.　Conclusions　The cervical anterior approach could reach the posterior longitudinal ligament through intervertebral disc, and enter the posterior longitudinal ligament space. This approach is valuable for protecting dura mater, spinal cord and spinal roots.