身体姿势对腰椎小关节受力的影响

Effect of body posture on the lumbar facet joints in resisting force

目的 :分析脊柱处于不同姿势时腰椎小关节受力大小及变化情况。方法 :采用 8具新鲜脊柱腰骶段 (L1～S1)标本 ,在MTS系统上用压敏片测量L4、5小关节面在中立位和前屈、后伸位时受力大小。结果 :中立位时L4、5小关节受力为 (3 1.16± 7.15 )N ,占轴向压缩载荷的 15 % ;前屈时小关节受力减小 ,前屈 10°、2 0°时受力大小为 (18.3 2± 4.46)N、(9.3 8± 1.82 )N ,占压缩载荷的比例减为 9%、5 % ;后伸时小关节受力增大 ,后伸 10°、2 0°时受力大小为 (4 5 .92± 11.0 6)N、(65 .68± 10 .16)N ,占压缩载荷的比例增至2 3 %、3 3 %。结论 :腰椎小关节在中立位能承受脊柱的一部分压缩载荷 ,且随脊柱姿势不同小关节面受力也不同。

Objective: To study the relationship between the body posture and the borne force of lumbar facet joints. Methods: Eight fresh lumbar-sacral spinal (L 1～S 1) specimens were placed on the MTS system. The borne forces of the two facet joints of the L 4,5 motion segments were measured using pressure sensitive films when the specimens were in erect, flexed and extended postures. Results: In erect posture the facet joints were subjected to 31.16±7.15N force(15% of the axial compression forces). In flexed posture the loaded forces of the facet joints decreased. When the specimens were at 10 and 20 degrees flexion, the borne forces were 18.32±4.46N (9% of the compression force) and 9.38±1.82N (5% of the compression force). In extension posture the forces of the facet joints increased. In the posture of 10 and 20 degrees extension, the forces were 45.92±11.06N (23%) and 65.68±10.16N (33%). Conclusion: The lumbar facet joints can share some of the compression forces of the spine in erect posture. And the proportion of share changes with the change of posture.