Answer:
They are usually divided into 3 groups:
Cervical (7, Neck)
Thoracic (12, Chest)
Lumber (5, Abdomen)
They are then given numbers starting at the top (eg. C1 (Cervical 1), C2, C3, T1, L3 ect.)
Some have individual names like 'Atlas' or 'Axis' but this is uncommon.