View Full Version : Strange dark scab/bumps behind knees

09-22-2006, 07:30 PM
I know this is going to sound strange and I'm hoping someone will be able to answer my question. If not, I will have to remember on my son's next dr. appt to ask this question. I noticed after my son was home from the hospital following his surgery that he has two dark scab/bumps behind both of his knees. It looks like he was poked there with something and I don't know why or what it was for? Part of me is not sure if I want to know. He still has the marks there I don't if he will have a scar from it now.

09-23-2006, 12:21 AM

I wonder if they hooked up the spinal cord monitor there.


Karen Ocker
09-23-2006, 03:14 PM
Linda is right.

These are from the electrode placement for the nerve/spinal cord monitoring monitoring:

For the lower SEP (legs), two stimulus electrodes are attached to the inside of your ankle, in such a way as to produce an involuntary twitch of the big toe. Additional sensor electrodes are placed at the back of the knee (closer to the outside), on the spine of the lower back, and on the spine of the upper back. Electric pulses are then sent at a rate of several times a second, and the responses are recorded in the same manner as above

This is a simplified explanation from wikipedia which I do not normally consult but the scholarly articles I checked do not give the technique just the reasoning.


Here is a professional article describing electrode placement which confirms the wickipedia article: ode+placement&hl=en&gl=us&ct=clnk&cd=28&lr=lang_en

09-23-2006, 04:09 PM
Thanks, Karen and Linda.