l4ti LIGAMENTS OF THE PELVIS. 



The posterior costo-sternal ligament is much smaller than the anterior, 

 and consists only of a thin fasciculus of fibres situated on the posterior 

 surface of the articulation. 



The superior and inferior costo-sternal ligaments are narrow fasciculi 

 corresponding with the breadth of the cartilage, and connecting its supe- 

 rior and inferior border with the side of the sternum. 



The synovial membrane is absent in the articulation of the first rib, its 

 cartilage being usually continuous with the sternum ; that of the second 

 rib has an interarticular ligament, with two synovial membranes. 



The sixth and seventh ribs have several fasciculi of strong ligamentous 

 fibres, passing from the extremity of their cartilages to the anterior surface 

 of the ensiform cartilage, which latter they are intended to support. 

 They are named the costo-xiphoid ligaments. 



The six, seventh, and eighth, and sometimes the fifth and the ninth 

 costal cartilages, have articulations with each other, and a perfect synovial 

 membrane. They are connected by ligamentous fibres which pass from 

 one cartilage to the other, external and internal ligaments. 



The ninth and tenth are connected at their extremities by ligamentous 

 fibres, but have no synovial membranes. 



Actions. The movements of the costo-sternal articulations are very 

 trifling ; they are limited to a slight sliding motion. The first rib is the 

 least, and the second the most movable. 



8. Articulation of the Sternum. The pieces of the sternum are con- 

 nected by means of a thin plate of interosseous cartilage placed between 

 each, and by an anterior and posterior ligament. The fibres of the ante- 

 rior sternal ligament are longitudinal in direction, but so blended with the 

 anterior costo-sternal ligaments, and the tendinous fibres of origin of the 

 pectoral muscles, as scarcely to be distinguished as a distinct ligament. 

 The posterior sternal ligament is a broad smooth plane of longitudinal 

 fibres, placed upon the posterior surface of the bone, and extending from 

 the manubrium to the ensiform cartilage. These ligaments contribute 

 very materially to the strength of the sternum and to the elasticity of the 

 front of the chest. 



9. Articulation of the Vertebral Column with the Pelvis. The last 

 lumbar vertebra is connected with the sacrum by the same ligaments with 

 which the various vertebra? are connected to each other ; viz. the anterior 

 and posterior common ligaments, intervertebral substance, ligamenta sub- 

 flava, capsular ligaments, and inter and supra-spinous ligaments. 



There are, however, two proper ligaments connecting the vertebral 

 column with the pelvis ; these are, the 



Lumbo-sacral, Lumbo-iliac. 



The lumbo-sacral ligament is a thick triangular fasciculus of ligamentous 

 fibres, connected above with the transverse process of the last lumbar ver- 

 tebra ; and below with the posterior part of the upper border of the 

 sacrum. 



The lumbo-iliac ligament passes from the apex of the transverse process 

 of the last lumbar vertebra to that part of the crest of the ilium which sur- 

 mounts the sacro-iliac articulation. It is triangular in form. 



10. The Articulations of the Pelvis. The'ligaments belonging to the 

 articulations of the pelvis are divisible into four groups . 1. Those connect- 



