Abstract： Objective To analyze lumbar nerve root compression with intervertebral foramina via comparing foraminal stenosis(FS)and foraminal hernia(FH)with lumbar canal stenosis(LCS). Methods Fifty one patients(12 cases of foraminal stenosis,18 cases of foraminal hernia and 21 cases of lumbar canal stenosis)who underwent surgical treatment from Jan 2004 to Aug 2009 were analyzed retrospectively. Japanese orthopaedic association scores,intervertebral disc degeneration,anatomical measurements of the nerve root foramina and the MRI findings were reviewed.Results Anterior-posterior diameters of the nerve root foramina in the FS group and FH group were smaller than these in the LCS group [LCS(11.4 ± 3.1)mm,FS(8.3 ± 3.0)mm and FH(8.3 ± 2.4)mm].More degenerated discs and shorter length of upper part of the nerve root foramina were seen in FS group (P ＜0.01).The MRI images of so-called black out nerve root foramina were positive in 66.7％(8/12)of FS cases and 7.8％(14/18)of FH cases.Conclusion Analyzing clinical and imaging characteristics of foraminal nerve root disorders of the lumbar spine can help diagnosis and treatment.