抄録
We investigated 60 cadavers to examine the accurate location of conus medullaris, lower end of dura mater,and intercrestal line (Jacoby's line).
Jacoby's line was established using the method described by Jacoby GW (1899). Then the intersection of this lineand vertical line through the spinous processes was marked by a fine nail. After a laminectomy was performed to exposethe spinal cord, spinal level of the conus medullaris, the lower end of dura mater, and Jacoby's line were examined, andmarked and recorded these locations of nailing.
In 2 of 48 cases (2.1%), Jacoby's line passed through the level superior to 3rdlumber vertebra (L3). The Conusmedullaris was at the level beneath L3 in 2 of 57 cases (3.5%). And lower end of dura mater was located beneath thesuperior margin of S3 in 1 of 28 cases (3.6%). When Jacoby's line is used as a guide-point, the site for subarachnoidpuncture is established in the L3-4 interspinous space. But when we consider the risk of spinal cord injury cannot becompletely excluded, in case that conus medullaris is located inferior to L3 in 3.5% of cases. Conseqently, it should beimportant to avoid performing subarachnoid puncture at L2-3 or higher lumbar vertebral level especially in the elderly.
