- Discussion: (Innervation of the Leg and Foot)
- arises from femoral nerve in femoral triangle and descends through it on lateral side of the femoral vessels to enter the adductor canal.
- it crosses the vessels obliquely to lie on their medial side in front of lower end of adductor magnus muscle;
- nerve continues its descent on medial side of knee, pierces fascia lata between tendons of sartorius & gracilis, & then passes downward on
medial side of leg close to greater saphenous vein;
- at lower end of canal, it leaves femoral vessels & gives off its infrapatellar branch, & runs onward to supply skin over medial side and front of knee and patellar ligament
- saphenous nerve lies posterior to sartorius in 60%;
- sartorial branch: lies posterior to the sartorius;
- infrapatellar branch
- nerve exits the adductor canal and travels to the anteromedial aspect of the knee;
- position relative to the fascia: at the level of the knee the nerve will be extrafascial in 43%
- in the lower leg, it subdivides:
- one branch follows the medial tibial border to the level of the ankle.
- larger passes anterior to medial malleolus to innervate skin on medial and dorsal side foot;
- changes in Nerve Position w/ Knee Flexion:
- in extension, saphenous nerve & all infrapatellar branches cross medial joint line anterior to posteromedial corner & are located 2-3 cm
anterior to semitendinosus tendon;
- in flexed knee, saphenous nerve and its branches cross medial joint line at, or slightly behind, posteromedial corner of knee;
- Saphenous nerve block:
- provides anesthesia over the medial portion of foot;
- subcutaneous "field block" with continuous wheal from lateral margin of achilles tendon around the anterior ankle to the medial margin of
the achilles tendon will anesthetize all superficial nerves of the foot: superficial peroneal, saphenous, and sural;
- New York School of Regional Anesthesia.
- Anesthesia UK.