Origin of Median Sacral Artery with Fourth Pair of Lumbar Artery - an Alert for Spine Surgeons and Interventionalists: A Case Report and Mini Literature Review.

The median sacral artery (MSA) is the single unpaired dorsal branch of the abdominal aorta. The present case describes the relatively unusual origin of the median sacral artery in common with the fourth pair of lumbar arteries via a common trunk in a 74-year-old males' cadaver. Unusual common trunk is prone for iatrogenic injury in surgeries of the lumbar and pelvic region. Owing to the deep seated nature of MSA close to the periosteum of lumbar vertebrae and sacrum, detection of accidental rupture of MSA and ligation thereof becomes a difficult task. MSA is also increasingly being utilized for intra-arterial embolization of pelvic tumours. The proximal portion of the common origin may at times undergo cone shaped dilatation which is referred to as infundibulum or infundibular dilatation and can also transform into aneurysm later. Knowledge of this variation is imperative for spine and pelvic surgeons to avoid unwanted complications.