<prompt> Rib ossification center first appears in which rib ?1st12th6th3rd  <response>: Ans. is c i.e., 6thEach rib except for 11th 12th is ossified from four centres :-One primary centre--for bodyThree epiphyseal secondary centres for :-HeadAicular pa of tubercleNon aicular pa of tubercleOssification begins near the angle toward the end of 2 month around 8th week of fetal life, and is seen first in 6th and 7th ribs.The epiphyses for the head and tubercle make their appearance between 16th and 20th years, and are united to the body about the 25th year. 