“When you hear the sound of hooves, think horses, not zebras.”
This phrase is taught to medical students throughout their training.
In medicine, the term “zebra” is used in reference to a rare disease or condition. Doctors are taught to assume that the simplest explanation is usually correct to avoid patients being misdiagnosed with rare illnesses. Doctors learn to expect common conditions.
But many medical professionals seem to forget that “zebras” DO exist and so getting a diagnosis and treatment can be more difficult for sufferers of rare conditions. Ehlers-Danlos syndrome is considered a rare condition and so EDS sufferers are known as medical zebras.