Ribs are classified as flat bones.  They articulate with the thoracic vertebra at the transverse facet and superior+inferior costal facets of the vertebra body posteriorly and with the sternum anteriorly.

The seven pairs of ribs that connect via costal cartilage to the sternum directly are known as true ribs.  Ribs 8-12 are thus known as false ribs; they either connect indirectly to the sternum by way of the costal cartilage of the 7th rib, or are floating ribs (11th and 12th).

Since the head, neck and tubercle point towards the posterior side and subcostal groove the inferior direction, one can deduce whether a rib is left/right using these landmarks.  The pictures above are from a left rib.