A femoral nerve block is a type of regional anesthesia in which the femoral nerve, located in the groin area, is deadened to allow surgery in the leg or knee area. A femoral nerve block is most often used to facilitate knee surgery, though it also can be used for a surgery on the hip or the upper leg, including repair to the tendons of the quadriceps. Anesthetic is administered to the femoral nerve through the inguinal region, or the groin, leading to complete numbness from the groin and hip down past the knee and into the lower leg. Sometimes, a femoral nerve block is combined with a block administered to the sciatic nerve, allowing most of the lower body to be numbed for complex surgical procedures without making use of general anesthesia.

Unlike general anesthesia, a femoral nerve block carries much fewer risk of complications and is much easier to administer. With general anesthesia, there is always a risk of breathing difficulties or other problems that can at times be fatal. Therefore, a femoral nerve block, which allows complete nerve numbness to the area being treated in the surgical procedure, provides a safer, simpler alternative. Deciding which type of anesthesia to use, however, is always a choice made between the surgeon and the individual patient and is based on a number of factors.

In addition to functioning as an anesthetic during surgery, a femoral nerve block also can be used to help manage pain after surgery has been performed. Most commonly, the femoral nerve block is used in this way after surgery to the knee or femur. How much anesthetic is used and the type of anesthetic is determined by how the femoral nerve block is being used. A different type and amount of anesthetic might be administered for pain management than would be used for a surgical application, for example.

When administering a femoral nerve block, the anesthetician must locate the femoral nerve. This is accomplished by locating the femoral artery by finding the pulse in the patient's groin. Another landmark used to located the femoral nerve is the femoral crease. Although administering a femoral nerve block is usually not terribly painful for the patient, some patients prefer slight anesthetic or sedation during the procedure because they are uncomfortable with the necessary exposure of and contact with the groin area. Again, the decision whether to use additional sedation in order to administer the nerve block is up to the doctor and the patient involved.