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Constrictive myelopathy is an acquired, circumferential constriction of the spinal cord that is presumed to develop secondary to pia-arachnoid fibrosis. It has also been termed subarachnoid fibrosis, pia-arachnoid fibrosis, and arachnoid scarring. Constrictive myelopathy is sparsely reported in the literature, with pugs possibly overrepresented. The author describes the condition's clinical signs, breed predilection, advanced imaging findings (including MRI and CT examples), treatment and outcome.