Lower Extremity Blocks#

Popliteal Sciatic#

  • covers 80% circumferential around ankle (anterior, lateral, posterior)

  • covers most of foot

  • motor block to foot & calf

  • no motor block to hamstrings (extends leg)

  • thigh tourniquet usually above coverage

  • positioning: elevate leg or lateral

popsci-position

popsci-injection

popsci-dermatome

Note: Sciatic Nerve block can also be done at subgluteal level (more proximal) if no access to popliteal fossa

  • more challenging as sciatic nerve is much deeper (~7+ cm)

  • may require curvilinear probe

  • also will block hamstrings

Saphenous (Adductor Canal)#

  • covers 20% medial side of ankle

  • covers medial side of foot to toe

  • covers part of knee

  • saphenous nerve is pure sensory, no motor block

saphenous-position

saphenous-injection

saphenous-dermatome

Femoral#

  • covers medial thigh & knee

  • blocks quadricep muscles (extends knee)

  • obese patients - tape pannus away from groin

femoral-position

femoral-injection

femoral-dermatome

Fascia Iliaca#

  • Fascial plane block

    • can be difficult to identify fascial plane

  • Coverage:

    • femoral nerve - 100% of cases

    • lateral femoral cutaneus (LFCN) - 80-100% of cases

    • obturator nerve - sometimes

  • useful for skin graft harvest site & hip surgeries

  • 2 approaches:

    • Infrainguinal - similar view as femoral

    • Suprainguinal - better for getting wider spread (e.g. LFCN, obturator)

fasciailiaca-injection

fasciailiaca-3nerves

Suprainguinal Fascia Iliaca Block:

fasciailiaca-dermatome

Sources#

Most of resources/images taken from NYSORA which is a good site for learning/review. https://www.nysora.com/techniques/lower-extremity/