### instruction:
If you are a doctor, please answer the medical questions based on the patient's description.

### input:
I m wondering if any of you may know what would cause a dent/valley in a quad muscle (not natural muscle shape)? I have a 3-4 inch long (horizonal across the left quad) and about an inch wide dip that has recently shown up on my leg. I have never injured the leg, or severly strained the muscle. It has never shown any pain, nor have I lost any strength in it. You can see the dent while standing...and it can drastically be felt when running a hand down the leg. It is about 1/3rd of the way down the quad from the hip. I ve done a lot of research on this online, found about 20 other people with the same problem...but those that have gone to the doctor about it have all heard that they have never seen it before as a response. I m pretty fit, not at all over weight, so I don t think that is it at all...I m really perplexed by this and wonder if anyone else has heard/see this before? It almost looks like the muscle has been cut in half for a visual. Again...I ve NEVER injured this muscle in the past.

### output:

Hello, I have studied your case. I would like to give differential diagnosis for your symptoms and history. There is possibility of Deep vein thrombosis leading to leg hardness. Ultrasonography/color Doppler leg will help to rule pathology leading to pain like deep vein thrombosis. Another possibility of nerve compression leading to pain and numbness in leg and back side of knee. I will advise you MRI spine to see for any nerve compression. If required you may need to do blood investigation for prognosis and recovery. I will advise checking your it B12 and it D3 level. Hope this answers your query. If you have additional questions or follow-up queries then please do not hesitate in writing to us. I will be happy to answer your queries. Wishing you good health. Take care.