TABLE 1.

Causes of spinal canal lesions according to the site of origin¹,³.

Intramedullary	Extramedullary, Intradural	Extradural
Syringomyelia, hydromyelia	Meningioma	Herniated disk
Intramedullary tumor (e.g., ependymoma, astrocytoma)	Neurof broma	Spinal stenosis, spondylosis, osteophyte
Inf ammation (e.g., abscess, myelitis)	Metastasis (e.g., leptomeningeal seeding or hematogenous)	Ligamentum f avum thickening, intraspinal ligament ossif cation
Multiple sclerosis		Meningioma
		Neurogenic tumor (e.g., neurof broma)
		Metastasis
		Vertebral neoplasm with intraspinal extension