ABSTRACT
Anatomical and clinical studies were carried out to clarify the anatomical structures related to the femoral nerve block at two levels, the inguinal ligament and the inguinal crease. The anatomical study was made on 30 lower limbs. The relation between the femoral nerve and artery, width and depth of the nerve was studied. At the inguinal ligament, the femoral nerve was lateral to the femoral artery in all cases; while, at the inguinal crease, the nerve was adherent to or partially covered by the artery in 10% of the cases; while in 90%, the nerve was lateral to the artery. There was a significant difference between both levels. The clinical study was made by inserting the needle for nerve block lateral to the femoral artery at two levels, the inguinal ligament and crease. The sensory block started after 11 +/- 3 minutes and the motor block after 18 +/- 2 minutes in patients subjected to femoral nerve block at the inguinal crease level. These were significantly earlier than at the inguinal ligament level where the sensory block started after 15 +/- 2 minutes and the motor block after 21 +/- 1 minutes. This was explained by the anatomical findings of the increased width of the femoral nerve and its more superficial position together with the more predictable femoral nerve femoral artery relationship at the inguinal crease level