Anatomical variations of the posterior intercostal arteries and the thoracic vertebral artery.

This study evaluated the occurrence and frequency of the anatomical variations of the origin and course of the posterior intercostal arteries (PIA) in 44 human cadavers. During a classical anatomical dissection of each cadaver an anomalous course of the PIA, defined as a thoracic vertebral artery, was found in six (14%) individuals. Every dorsally coursing PIA was taken into account, regardless of its origin, and their different origins and course were described. A specific dorsal course for the PIA was found in nine cases, which was bilateral in two cases. The variations that were found and that have been schematically presented will provide new information about the anatomical variations of the PIA. Consideration of the potential for anatomical variation of the PIA is important in vascular and thoracic surgery and in diagnostic and interventional radiology such as spinal angiography.