key vein

key vein

a deep-seated, dilated vein causing a so-called spider burst on the surface.
References in periodicals archive ?
The CEO of NTL Matthew Hill has revealed that the company is elated to work on the Rahu Project with Newcrest since it possibly will host a key vein system with similar depths to other deposits in the Waihi Gold District.
Instead he recorded that Megan died before birth as a result of a common condition called velamentous insertion of the umbilical cord which caused key veins to be squashed in the narrow birth canal, depriving the brain of blood and oxygen.