pterygium

The word pterygium entered medical Latin directly from Greek pterygion, a diminutive of pteron (wing). The suffix -ion in Greek made things smaller and more specific, and pterygion was a little wing. The name described the triangular fold of pink tissue that grows from the inner corner of the eye toward the pupil. Galen of Pergamon, writing in the second century CE, used the term for the fleshy growth that ophthalmologists still call by its Greek name today.

The condition itself is older than any written description of it. It grows most often in people who spend years in bright sunlight and wind, which meant farmers, sailors, and desert dwellers were its primary sufferers in antiquity. The Sushruta Samhita, the ancient Indian surgical text compiled around 600 BCE, describes a growth matching pterygium and records its removal by scraping. When Greek physicians named it pterygion, they were naming something their patients had already been living with for centuries.

Medieval Latin medical manuscripts carried the Greek term unchanged, and Renaissance anatomists working in Bologna and Padua kept it when they systematized ophthalmology in the 16th century. The treatment evolved from scraping to excision to the conjunctival autograft used today, but the name did not change. Andreas Vesalius in 1543 and his contemporaries catalogued pterygium among the diseases of the eye using the same Greek diminutive that Galen had used fourteen hundred years before.

In modern medicine, pterygium refers specifically to the fibrovascular growth on the conjunctiva that can encroach on the cornea and blur vision. The word has also migrated to anatomy, where pterygoid names two wing-shaped processes of the sphenoid bone at the base of the skull. Greek gave medicine a set of wing-words — pteron, pterygion, pterygoid — that still organize the vocabulary of shape in anatomical description.