Download Dissection of the Anterior Leg List of Steps to follow in Dissection

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