Arteriovenous malformations of the spine are classified into:

• type I: dural AV fistula
• type II: intramedullary glomus-type AVM
• type III: juvenile-type intra- and extramedullary AVM
• type IV: direct extramedullary AV fistula)

The type shown above is type III. Type III AVM often has extramedullary and extraspinal involvement and is typically fed by multiple vessels. Type III is more common in the cervical and thoracic spine. Type III lesions are considered congenital and typically present before age 30.

Image contributed by: Dr Laughlin Dawes.