All are atypical ribs except
The first 7 ribs which are connected through their cailages to the sternum are called true ribs, or veebrosternal ribs. The remaining five are false ribs. Out of these the cailages of the eighth, ninth and tenth ribs are joined to the next higher cailage and are known as veebrochondral ribs. The anteriorends of the eleventh and twelfth ribs are free and are called floating ribs or veebral ribs.The first two and last three ribs have special features and are atypical ribs. The third to ninth ribs are typical ribs.Ref: BD Chaurasia; Volume 1; 6th edition
I
II
IX
X
Thorax