ARTICULATIONS OF THE HEAD WITH THE NECK 267 



or joints, by which means tliey are enabled to move freely in the required 

 directions during respiration or breathing. 



CostO-Vertebral Articulations.— Each of these joints is formed by 

 the articulation of the head of a rib between the bodies of two vertebrae, 

 and by the union of the tubercle of the rib with the transverse process 

 of the vertebra behind it. Several small ligaments enter into each joint 



Fig. 349. — Articulation of tlic llil.s htjiI Siiine 



1. Common inferior vertebral ligament. 2, 2, 2. Inferior costo-vertebral ligaments. 3. Inter- 

 articular costo-vertebral ligament. 4. Inter-vertebral fibro-cartilage in section. 



and unite the ril) firmly to the spine, while at the same time permitting 

 free play of one bone upon the others. 



CostO-Sternal Articulations. — These are the joints formed by the 

 union of the infciiur extremities of the cartilages of the eight true ribs 

 with the sternum or breast-bone. Each articulation has a capsular liga- 

 ment lined by a synovial membrane, and two other connecting ligaments 

 extending from the costal cartilage above and below to the sternum — 

 superior and inferior costo-ifternal ligaments. 



ARTICULATIONS OF THE HEAD WITH THE NECK 



OccipitO-Atloid. — The union of the head with the neck is effected by 

 the articulation of the two occipital condyles with corresponding concavities 



