Cardiac dominance is based on ?
Anterior interventricular aery
Posterior interventricular aery
Circumflex aery
None of the above
Ans. is 'd' i.e., 10thRibsThere are 12 pairs of ribs. All aiculate posteriorly with thoracic veebrae. The ribs are divided into two types.True ribs or veebrosternal ribs :- These are lst to Th ribs which aiculate directly with sternum through costal cailages.False ribs :- These are 8" to 12th ribs and do not aiculate directly with sternum. False ribs can be divided into:Veebrochondral ribs :- 8th,9th and 10th ribs whose costal cailages aiculate with each other and with 7th costal cailage forming costal margin,Floating ribs (veebral ribs) :- 11 ''' and 12th ribs have free anterior ends.The ribs can also be divided into ?Typical ribs :- 3rd to 9th ribs are typical ribs because they bear common features and individual indentification is not possible.Atypical ribs (peculiar ribs) :- 1", 2nd, Oth, 11`h, and 12th ribs are atypical and each of them can be identified by special distinguished features.