132 THE ANATOMY OP THE HOESB. 



rouoh surface which is left when one set of fibres is removed from the 

 underlying set. 



Directions.— The joints and ligaments of the dorso-lumbar part 

 of the spinal column and of the ribs must now be dissected. 

 The ligaments of the lumbar region will be exposed by carefully 

 removing from the surface of the bones the remains of muscles 

 and other textures already examined. The whole of the dorsal 

 region need not be dissected in order to expose the ligaments, but it 

 will suffice to take a segment containing four or five vertebrae with their 

 costal articulations intact. The articulations of the costal cartilages to 

 the sternum are to be examined on the part of the thorax removed for 

 the display of the triangularis sterni muscle. 



ARTICULATIONS OF THE RIBS. 



Each rib is articulated to the spinal column at two points, viz., 

 by its head, and by its tubercle. The head is received into a cup- 

 like cavity formed by two adjacent vertebral bodies and the disc 

 that unites them. This is the costo-central joint. The tubercle articu- 

 lates with the flat facet on the transverse process belonging to the 

 posterior of the vertebrae to which the head is articulated. This is the 

 costo-transverse joint. 



CosTO-CENTRAL JoiNT. This possesses two ligaments — the costo- 

 vertebral and interarticular, and two synovial sacs. 



Fig. 13. 



two costo-vertebral, and two intervertebral joints, viewed from below. 



1. Attachment of costo-vertebral (stellate) ligament to intervertebral disc ; 2. and 3. Attachments 

 of the same ligament to the anterior and posterior vertebral bodies ; 4. Posterior costo-transverse 

 ligament ; 5. Intervertebral disc, covered by 6. the inferior common ligament. 



The Costo-vertebral or Stellate Ligament is placed beneath the joint. Its 

 fibres radiate from the rib just below its articular head, and become 

 attached to the body of the vertebra in front, to the body of the 

 vertebra behind, and to the intermediate disc. 



