Why is it called multiple sclerosis?
The word sclerosis comes from the Greek ‘skleros’ meaning hard. In multiple sclerosis, hard areas called ‘plaques’ (also known as lesions or scars) develop around the damaged nerves. ‘Multiple’ refers to the many different areas of the central nervous system that may have damaged myelin. The lesions show up on scans but having lots of lesions or scars isn’t always the same as saying that your MS is severe – many things about MS are complicated.
Source: Multiple Sclerosis Society (UK)