Coal, oil and natural gas are three main types of fossil fuels. Fossils fuels are combustible materials that are formed over millions of years by the decomposition of plant and animal life. Continue Reading.
Some of the possible common medical causes of Extremity pain may include: 1  Brachial plexus lesions. 2  Carpel tunnel syndrome. 3  Biceps tendonitis.  Raynauds 1  phenomenon. Sickle cell anemia.  Black widow spider 1  bites. Polyneuropathy.  Cat scratch 1  disease. Post herpetic neuralgia.  Erythema nodosum.
Traumatic injuries, repetitive strain injuries and certain medical conditions -- especially conditions involving the lower extremity blood vessels -- can cause pain in the back of your knee.