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Hummingbird sign

Dr Andrew Dixon and Dr Frank Gaillard et al.

The hummingbird sign, also known as the penguin sign, refers to the appearance of the brainstem in patients with progressive supranuclear palsy (PSP). The atrophy of the midbrain results in a profile of the brainstem in which the persevered pons forms the body of the bird, and the atrophic midbrain the head, with beak extending anteriorly towards the optic chiasm.