Background: The external opening of the carotid canal (EOCC). the entry point of the internal carotid artery into the skull. varies across populations. This study characterized the EOCC with the mastoid process (shortest distance from the EOCC to the tip of the mastoid process [SDTCC]). https://www.roneverhart.com/Dudley-ASA-Thunder-ZN-Hycon-12-52-300-Softballs-4A-068Y/