Answer: It is called DEMIFACET.
Step-by-step explanation:
Demifacet is the half of the facet it is the medium heart shaped flat face where part of the head of rib or part of coastal cartilage articulates and it is usually found from rib 2 to 9. It is the superior of the demifacet that receive the head of the rib I.e the head articulate to it.