Explanations and Causes:
The meniscus of the knee is a flat bi-lobed disc of cartilage that sits between the femur of the upper leg and the bones of the lower leg. Its function is to lubricate the movement, absorb the shock or compression, and limit over flexion or bending of the knee. [...]

Fibromyositis, fibrositis, periarticular fibrositis, chronic muscle pain syndrome, muscular rheumatism, myofascial pain syndrome

Explanation and Causes:
Gangrene is a condition that is characterized by the death of an organ or body tissue. It is a very serious condition that requires immediate medical attention.
There are 3 types of Gangrene:

Dry Gangrene
Wet Gangrene
Gas Gangrene

All three of these can be caused by:

Serious injury
Diabetes
Blood vessel disease such arteriosclerosis
Surgery
Infection

Symptoms:
General symptoms [...]