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Indications: femur, patella, quadriceps tendon, and knee sugery; analgesia for hip fracture (Figure 33A–1)
Transducer position: transverse, femoral crease
Goal: local anesthetic spread adjacent to the femoral nerve
Local anesthetic: 10–15 mL
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GENERAL CONSIDERATIONS
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The ultrasound (US)-guided technique of femoral nerve blockade allows the practitioner to monitor the spread of local anesthetic and needle placement and make appropriate adjustments to accomplish the desirable disposition of the local anesthetic. US also may reduce the risk of femoral artery puncture. Although nerve stimulation is not required for success, motor response observed during nerve stimulation often provides contributory safety information should the needle–nerve relationship be missed by US alone.
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Orientation begins with the identification of the femoral artery at the level of the femoral crease. Commonly, the femoral artery and the deep artery of the thigh are both seen. In this case, the transducer should be moved proximal until only the femoral artery is seen (Figure 33A–2a, b). The femoral nerve is lateral to the vessel and covered by the fascia iliaca; it is typically hyperechoic and roughly triangular or oval in shape (Figure 33A–3a, b). The nerve is enveloped within two layers of the fascia iliaca. The femoral nerve typically is visualized at a depth of 2–4 cm.
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Identification of the femoral nerve often is made easier by slightly tilting the transducer cranially or caudally. This adjustment helps bring out the image of the nerve, making it distinct from the background.
Applying pressure to the transducer ...