RESUMO
With the aim of further understanding of the nerve supply of the Iumbodorsal region,and its relation to the pathogenesis of lumbago and lumbocrural pain,the superior chnial nerves of lilty adult Chinese cadavers were dissected. In the present study,it was shown that the superior clunial nerve consists of lateral branches of the posterior rami of spinal nerves rarying from T_(12)L_(1～5)and S_1 segments. The contribution of these branches to this nerve is as follows,T_(12):40 cases,L_1 and L_2: 100 cases each,L_3:96 cases,L_4:48 cases,L_5:11 cases,and S_1:4 cases.Our observation revealed the fact that the posterior rami of L_(4,s)spinal nerves consist of a lot of lateral cutaneous branches,which is not in accordance with embroyological descriptions cited in literature which deny their existence. Basing on our data,we classify the superior clunial nerve into 4 types,Viz:one- branched:1 case;two-branched:15 cases;three-branched:66 cases;and four-branched:18 cases. More than one half of the medial and the most medial branches of the superior clunial nerves perforate through the deep surface of the attachment of the posterior layer of the lumbodorsal fascia on to the iliac crest,and enter the superficial fascia of the buttock.During acute wriggle of the loin,the firm fixation and tight stretching of the perforating branches by this attachment may cause partly the injury of the branches. The crossing point of the lateral margin of the sacrospinalis muscle and iliac crest or the area slightly medial to this point is the site where the perforating superior clun- ial nerve could be localized supeficialiy.