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Dissection of the Anterior Leg Typically the previous dissection would have been the removal of abdominal contents Note the ASIS Imagine a line going straight down the leg from the ASIS to the patella Now begin to look for the lateral femoral cutaneous nerve starting about 1cm lateral to this line about 10cm from the ASIS You will have to find the tough fascia lata and incise it Then look for the nerve Once you have found it use the Metz to follow it proximally and distally Once the nerve has been demonstrated leave it as dissecting the nerve too much leads to it becoming loose from tissue distally and then you will be unable to demonstrate it later Now find the lateral border of the Sartorius muscle to the medial side of the nerve and the tensor fascia lata muscle to the lateral side of the nerve Note the fascial layers around the lateral femoral cutaneous nerve and the relationship to the two muscles Follow the lateral border of the Sartorius all the way down Once you have done this it is time to place your finger under the muscle and digitally dissect the muscle away from the underlying fascia and tissue Try not to digitally dissect to far past the medial edge of the muscle You will want to now lift the lateral edge of the Sartorius up and inspect the medial edge of the muscle and try to find and see the nerve that go up to this medial edge\ These are the nerves to the Sartorius There is usually one proximal and one distal but the nerves will appear to enter into the medial edge The importance of these nerves has to do with the nerve stimulator technique and whether or not to accept a Sartorius twitch prior to injecting local for a femoral nerve block Dissect out the saphenous vein up into the groin and then down the medial aspect of the leg all the way into the lower leg This will give you an idea as to how close the saphenous nerve is to the vein, which really does not occur until about 10cm below the patella Go back to the Sartorius and having found the nerves to the Sartorius on the medial side note as you follow the lateral edge of the Sartorius down the leg that you will be able to see the blood vessels or femoral artery Recall that the femoral artery is the landmark you see under the Sartorius when doing a saphenous nerve block Review the anatomy of the femoral nerve Find the ASIS and the pubic tubercle then imagine the middle and that is where the femoral artery will be. Recall that the nerve is lateral to the artery and that the saphenous nerves goes form the lateral aspect of the artery to the medial aspect in its course down the leg Now find the artery under the Sartorius muscle about mid thigh Note the shiny fascia with striations or what appear to be white lines going through it This is the vasto-adductor membrane Now look above the membrane or more proximal to it and note the artery and see if you can find the nerve that is usually adherent to the artery use your Metz to peel it off the artery Do the same thing below the vasto adductor membrane and see if you can find the saphenous nerve on the medial side of the artery Once you have found the nerve follow it down and up using the Metz to help demonstrate it better As you follow it down the leg, feel for a very tough ligament that is going into the medial condyle of the femur This is the tendon of the adductor magnus and helps to form the adductor hiatus through which the femoral vessels enter the popliteal fossa Now find the tendon of the gracillis muscle Encircle the Sartorius with you thumb and index finger and feel for a tendinous bump that is below the Sartorius Recall that the saphenous nerve exits in between the Sartorius and the gracillis tendon and this usually occurs below the knee and the saphenous nerve will continue to go straight At the foot find the saphenous vein and nerve over the medial malleolus Follow this up for a while and remember that the vein is very flat in this area and the nerve may be very tiny Once you have found the saphenous vein you will now know where not to cut while dissecting for the posterior tibial nerve Cut the skin only 1-2cm lateral to the saphenous vein and take this cut over the malleolus and include the arch of the foot. Then make another cut at about the Achilles or calcaneal tendon and take that to the sole of the foot Now connect these two incisions along the sole of the foot and remove the skin Locate the tough fascia and incise it in between the malleolus and the heel You can also make an incision in the fascia above the malleolus Now try to find the posterior tibial artery and nerve Above the malleolus they can be hiding behind very faint fascia and look as if they are one with the underlying muscle Continue to follow the nerve once you have found it both proximally and distally