140 



'////: MiTH'ri.ATI' 



ARTICLE III. ARTICULATIONS OF THE THOIIAI. 



Thoso aro also divided into eftritwir and intrinsic. Tin- first, named 

 oosto-vt iteliral, unito the ribs to the spine. The second join the different 

 pieces of the thorax together; they comprise: 1, The chondro-flternal 

 articulations ; 2, Chondro-costal articulations ; 3, The articulations of tho 

 eo-ul cartilages with each other; 4, Tho sternal articulation peculiar to 

 the larger Ruminants and tho Pig. All thest) joints will bo first studied in a 

 particular manner, then examined in a general way as to their movements. 



1. Articulations of the Bibs with the Vertebral Column, or Costo-vertebral 



Articulations. 



Each rib responds to the vertebral column by two points its head ami 

 its tuberosity. Tho first is received into one of the iutervcrtebral cavities 

 hollowed out on tho sides of the spine, and is therefore in contact with two 

 dorsal vertebra) ; the second rests against the transverse process of the 

 posterior vertebra. From this arrangement arises two particular articulations 

 belonging'to the arthrodial class, which aro named costo-vertebral and custo- 

 transverse. 



COSTO-VERTEBRAL ARTICULATIONS. Articular surfaces. Pertaining to 

 the rib, we have tho two convex facets of the head, separated from each 

 other by a groove of insertion and covered by a thin layer of cartilage. 

 On the vertebne, tho concave facets which by their union form the inter- 

 vcrtebral cavity ; these facets are also covered with cartilage, and separated, 

 at the bottom of tho cavity by the corresponding intervertebral disc. 



Mode of union. 1. An interarticular liyament (Figs. 83, 2; 84, 1), im- 

 planted in the groove of insertion of the head of the rib, and attached to 



Fig. 83. 



Fig. 84. 



ARTICULATIONS OK TIIK IMIIS WITH Till. \ II:- 

 n. in: ]:, ANI> <>i TIII.SI; \\ i in i \, H ,.i m.i: 

 (iNri;u:ou I-LAXK). 



1, Intcnirtirulur coMu-viTtcl.r.-il ligament ; 

 2, .'t, 4, Fasciculi of tho stellate, <>r in- 

 ferior costo-vertcbral ligament ; .">, (.'<>MIIII<>U 

 inferior vertebral ligament. 



ARTICULATIONS OF THE RIBS WITH TIIK VKR- 

 TKIIK/K. AND OK THESE WITH EACH OTHER 

 (ri'l'KIl 1'I.ANK). 



1, Spinal canal, upper face, showing the 

 common superior ligament ; 2, Interar- 

 tinilar < -osto-vertebrul ligament; ''-, Inter- 

 is cos to-transverse ligament; 4, Pos- 

 terior costo-transverse ligament. 



tho superior border of the intcrvertebral disc, which it encircles upwards 

 and inwards, to unito on the median lino with the ligament of tho opposite 

 side. 2. An inferior periphery I liijunn /</ (Fig. 84, 2, 3, 4), flat above and 

 below, thin and radiating (whence it is often nanu-d tlic >7<7/// ligament), 

 formtxl of three fasciculi which arc fixed in commoti on the inferior face of 



