Fig. 60 * 



LIGAMENTS OF THE RIBS. J29 



separates the anterior from the posterior branch of the intercostal 

 nerves. 



The middle costo-transverse ligament is a very strong interosseous 

 ligament passing directly between the posterior surface of the neck 

 of the rib, and the transverse process against which it rests. 



The posterior costo-transverse ligament is a small but strong fascicu- 

 lus, passing obliquely from the tubercle of the rib, to the apex of the 

 transverse process. The articulation between the tubercle of the rib 

 and the transverse process is provided with a small synovia! mem- 

 brane. 



There is no anterior costo-transverse ligament to the first rib ; and 

 only rudimentary posterior costo-transverse ligaments to the eleventh 

 and twefth ribs. 



Actions. The movements permitted by the articulations of the 

 ribs, are upwards and down- 

 wards, and slightly forwards 

 and backwards ; the movement 

 increasing in extent from the 

 head to the extremity of the 

 rib. The forward and back- 

 ward movement is very trifling 

 in the seven superior, but great- 

 er in the inferior ribs ; the 

 eleventh and twelfth are very 

 movable. 



7. Articulation of the Ribs 

 with the Sternum, and with each 

 oilier. The ligaments of the 

 costo-sternal articulations are, 



Anterior costo-sternal, 

 Posterior costo-sternal, 

 Superior costo-sternal, 

 Inferior costo-sternal, 

 Synovia! membranes. 



The anterior costo-sternal ligament is a thin band of ligamentous 

 fibres, that passes in a radiated direction from the extremity of the 

 costal cartilage to the anterior surface of the sternum, and intermingles 

 its fibres with those of the ligament of the opposite side and with the 

 tendinous fibres of origin of the pectoralis major muscle. 



The posterior costo-sternal ligament is much smaller than the ante- 

 rior, and consists only of a thin fasciculus of fibres situated on the 

 posterior surface of the articulation. 



* A posterior view of a part of the thoracic portion of the vertebral column, 

 shewing the ligaments connecting the vertebrae with each other and the ribs 

 with the vertebrae. 1, 1. The supra-spinous ligament. 2, 2. The ligamenta 

 subflava, connecting the laminae. 3. The anterior costo-transverse ligament. 

 4. The posterior costo-transverse ligaments. 



K 



