Both vertebral arteries drop a branch as they enter the skull and these branches unite on the anterior aspect of the spinal cord (actually in a deep sulcus) to form the anterior spinal artery.

The artery courses the full length of the spinal cord and supplies the anterior horn of the cord and the tracts located in the anterior and lateral portions of the spinal cord {see cross-sectional view}.

Along its course, the artery is supplemented by radicular branches which come off the aorta and enter along the nerve roots. There are a variable number of these, but the largest and most important is usually found supplying the lumbar enlargement - its name is the Artery of Adamkiewicz; this artery enters most frequently on the left side of the person [note orientation].

The arterial supply of the mid and lower thoracic spinal cord is marginal and the cord can be infarcted if there is a systemic drop of blood pressure (e.g., shock), or if the artery of Adamkiewicz is cut during operations involving the aorta.