σκλήρωσις

The ancient Greek sklērōsis (σκλήρωσις) derived directly from the adjective sklēros (σκληρός), meaning hard, dry, harsh — used of both physical texture and personality in Greek writing. In the medical tradition descended from Hippocrates, sklēros described the palpable hardness of diseased tissue: the indurated, firm, resistant texture that the examining physician's fingers detected when pressing into a nodule, a tumor, or an affected organ. Ancient and medieval physicians performed physical examination primarily by touch — before imaging, before laboratory testing, the hand on the body was the primary diagnostic instrument, and what the hand found was often described in the vocabulary of texture.

Medieval Arab physicians, working from Greek medical texts and their own clinical observation, incorporated the concept; Ibn Sina's Canon of Medicine described hardening of organs as a pathological process, using the Arabized Greek terminology. When European physicians in the 16th and 17th centuries began systematic anatomical dissection, they found correlates for what the hand had palpated: arteries that had turned calcified and rigid, liver tissue that had become fibrous and leathery, nerve tissue that had developed plaques of abnormal consistency. The Latin translation of sklērōsis — sclerosis — entered European medical terminology as the name for this pathological hardening process.

The 19th century mapped sclerosis onto specific diseases with increasing precision. Atherosclerosis — from Greek athērē (gruel, porridge) describing the lipid-filled plaques of arterial walls — was distinguished from arteriosclerosis (simple arterial hardening with age). Multiple sclerosis was named in the 1860s by the French neurologist Jean-Martin Charcot, who identified the hardened plaques of demyelinated nerve tissue in the brains and spinal cords of patients with the characteristic neurological symptoms; the word multiple referred to the multiple sites of hardening scattered through the nervous system. Amyotrophic lateral sclerosis — ALS — named the hardening of the lateral columns of the spinal cord accompanying motor neuron degeneration.

Today sclerosis functions primarily as a suffix in a family of serious and often progressive diagnoses: multiple sclerosis, amyotrophic lateral sclerosis, primary lateral sclerosis, systemic sclerosis (scleroderma), tuberous sclerosis, atherosclerosis, cirrhosis (from Greek kirrhos, tawny — the color of fibrotic liver). In each case, the Greek sensation of hardness under the physician's fingers has become the pathological mechanism: abnormal fibrosis, calcification, or demyelination replacing healthy tissue with something resistant and rigid. The hand that felt hardness in ancient Greece named a process that MRI machines now image across billions of neurological examinations.