Of the 24 (not counting the sacrum and coccyx), two vertebrae are fortunate enough to have names. The atlas (C01) and axis (C02) are two of the most important vertebrae in the spine. Without them, head and neck movement would be impossible and therefore dancers wouldn’t be able to spot!
The atlas and axis vertebrae are the two most superior bones in the vertebral column. They are part of the seven cervical vertebrae. The atlas is the top-most bone, sitting just below the skull; it is followed by the axis. Together, they support the skull, facilitate neck movement, and protect the spinal cord. (Think of them as BFFs—you won’t find one without the other.)
With all this in mind spotting has to happen with the rotation of the atlas around the axis. When executed properly the actual back of your neck will lengthen. Spotting will then generate from the base of the skull not the bottom of the neck.