Regional anaesthesia · Lower limb
Lower-limb blocks
Blocks for the hip, knee, thigh, ankle and foot: how to do them, what they cover and what they weaken, and which one to choose for the operation in front of you.
Four pages
Choose a region
Each page covers anatomy, position, equipment, technique, dose, coverage and complications, with animated demonstrations, a simulated ultrasound scan with the needle and spread, exam questions, and consultant and frontier notes.
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Page 1 · Hip
Hip
- PENG and lateral femoral cutaneous
- Fascia iliaca, supra- and infra-inguinal
- Femoral nerve block
- The hip fracture pathway
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Page 2 · Knee
Knee
- Femoral triangle and adductor canal
- iPACK and genicular nerve blocks
- Obturator, and the obturator jerk
- The motor-sparing knee plan
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Page 3 · Foot and ankle
Foot and ankle
- Popliteal sciatic
- Ankle block, ultrasound and landmark
- Saphenous at and below the knee
- Tourniquets, foot drop, the numb heel
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Page 4 · Thigh
Thigh and amputation
- Subgluteal sciatic, and the other levels
- Posterior femoral cutaneous nerve
- Amputation planner
- Block combinations and total dose
Rapid fire
Eight things to know before any lower-limb block
- Femoral nerve = quadriceps. A femoral or fascia iliaca block weakens the leg: check strength before the first stand. Choose PENG or an adductor canal block when the patient must walk.
- Fascia iliaca does not reliably block the obturator nerve, whatever the volume.
- Popliteal misses the saphenous strip: the medial leg and the medial malleolus. Add a saphenous block.
- An ankle block numbs the foot, not the ankle joint: the joint branches leave above the malleoli.
- Ask where the cuff goes. Ankle cuff: ankle block. Calf cuff: popliteal + saphenous. Thigh cuff: spinal or general anaesthesia.
- A spinal does not stop the obturator jerk. Block the obturator nerve before the resection.
- A numb foot can’t warn you: float the heel, pad the fibular neck, and think compartment syndrome when new pain breaks through.
- Count every milligram, the surgeon’s infiltration included. A common ceiling for ropivacaine is about 3 mg/kg (lean body weight), lower in the frail.
What each block costs in muscle
- PENG
- Usually none. Quadriceps weakness if fluid reaches the femoral nerve.
- LFCN
- None. Purely sensory.
- Fascia iliaca, femoral
- Quadriceps. The knee buckles: falls.
- Adductor canal
- Largely spared. Vastus medialis if too proximal or too much volume.
- iPACK, genicular
- None. iPACK can spread to the tibial or common peroneal nerve.
- Obturator
- Hip adductors.
- Sciatic, popliteal
- Foot drop, no push-off; the hamstrings too with the subgluteal level.
- Ankle
- Intrinsic foot muscles only. Walks on the heel.
Across all four pages
Which block for which operation
Pick an operation to see the area to cover, the recommended block and the alternatives with their doses, what they miss, the tourniquet, and links to each block’s chapter.
Doses are ropivacaine for an adult, as used on the block pages. They are starting points: adjust for weight, age, frailty and every other local anaesthetic the patient receives.
Local anaesthetic systemic toxicity. Lower-limb combinations use large volumes, often in frail or sick patients: two or three blocks plus the surgeon’s infiltration can pass the maximum dose. Add up the milligrams before you start, inject in small aliquots with aspiration, and know where the lipid emulsion is.