What may cause numbness in only one area on sole of my right foot. i have 75% blockage in artery in left side near groin. not a diabetic .

No blood-no function: You need to be under the care of a vascular specialist to see your options of treatment for a 75% arterial blockage. If you are getting inefficient flow in the lower extremities, it may be compromised on the right side as well and resulting on inefficient nerve function. Diabetic have a higher risk of vascular problems, but they are not the only patients that can suffer from this condition.

Many possibilities: Numbness can occur from various reasons. Some potential causes include vitamin deficiency, nerve damage, nerve compression, and alcohol over consumption, side effects of different medications, or as a result of different systemic medical conditions such as diabetes. Get evaluated by a professional to determine the diagnosis. Treatment is based on the diagnosis.