Meaning of carotid sinus

carot'id si"nus

Pronunciation: [key]
— Anat. Anat.
  1. specialized nerve end organs producing a slight dilatation of the carotid artery where it branches into the external and internal carotid arteries, responding to changes in blood pressure by mediating changes in the heartbeat rate.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.