Solitary aneurysms of the extramedullary arteries of the spinal cord, not associated with arteriovenous malformations from which they are clinically indistinguishable, are rarely reported; only four cases have appeared in the recent literature. An aneurysm of the great anterior radicular artery of Adamkiewicz was found at autopsy in a 34-year-old pregnant woman. The aneurysm had ruptured into the subarachnoid space.