Anatomy. The C6 vertebra is located in the inferior end of the neck just above the thorax. It is the second most inferior cervical vertebra as well as the second largest; only the C7 vertebra is larger and more inferior....natomy The C6 vertebra is located in the inferior end of the neck just above the thorax. It is the second most inferior cervical vertebra as well as the second largest; only the C7 vertebra is larger and more inferior.... Click to read more below.