<prompt> Chassaignacs tubercle lies at the level of -Erbs pointStellate ganglionAtlasOdontoid process  <response>: Erbs point is opposite chassaignacs tubercle tubercle on transverse process of C6 vertebra, 2-3 cm above the clavicle, slightly outside the lateral border of sternocleidomastoid.Chassaignacs tubercle is carotid tubercle on C6 vertebra, and it lies at the level of Erbs point.Option b also requires some explanation here. Stellate ganglion block is given most commonly by using chassaignacs tubercle as a landmark. But stellate ganglion itself lies at the level of the transverse process of C7 vertebra. 