The femoral nerve and its relationship to the lateral circumflex femoral artery.

Small branches of the femoral artery in the femoral triangle are not palpable and could increase the risk of intravascular injection during femoral nerve (FN) block. I evaluated the position of the lateral circumflex femoral artery (LCFA), a lateral branch of the femoral artery, in relationship to accepted landmarks for FN blockade, including the inguinal ligament, inguinal crease, and FA. Forty cadaver lower extremities were dissected. In 50% of specimens, the LCFA, as it crossed the FN, was within 1 cm of the inguinal crease, the recommended level for needle insertion for FN blockade. The mean depth of this artery at the inguinal crease was 1.7 cm, whereas the mean depth of the FN was 1.1 cm at this level. In most specimens, the LCFA coursed between the branches of the FN, although it sometimes lay deep to all of the branches. Knowledge of this anatomy may allow for safer FN blockade.