66 TOPOGRAPHICAL ANATOMY OF THE 



the convexity of the rib to move in a lateral direction. This occurring 

 simultaneously on both sides of the body, tlie transverse diameter of the 

 chest is materially increased. 



During movement of the rib as a whole, its tubercle glides on the 

 vertebral transverse process in the arc of a circle, the centre of which is 

 at the capitular attachment of the interarticular ligament. 



From the differences in the curve of the various ribs, as well as from 

 certain differences in the form of their articular surfaces, it is evident 

 that the possible range of movement increases from the first backwards. 

 It is also evident that extensive movement of those sternal ribs to which 

 the thoracic limbs are applied is undesirable. 



