SUPPORT, MOTION, AND SENSATION 



331 



veloped, composed of ribs attached to a ventral breastbone (sternum) 

 and to the dorsal backbone. Ascending the evolutionary tree farther 

 the organism became better adapted to turn the head. A fish or 

 frog must not only roll the eyes but also change the entire position 

 of the body in order to look behind. Not so with a cat, which may 



cervical 



vertebrae" 



rooCitcs 

 iclncc 



Cranxum. 



clavicl© 



L /..scapula. 



-thoracic sternuTn 

 vertebrae 



lumbar 

 v©rt<atorcc© 



-5ctortxm 



Carpus 



patella 



tibia, 

 fxbula,. , 



1 1 fl / f i// 



In/ 1/ i//j 



.tarsus 

 mata-torsLrs 



Human skeleton. Can you recognize the bones of a disarticulated skeleton.^ 



roll its eyes and is also able to turn its head. This ability to rotate 

 the head is due to varying numbers of cervical, or neck, vertebrae. 

 Four-footed animals are further characterized by four other sets of 

 vertebrae, thoracic (with ribs), lumbar (without ribs), sacral (for the 

 attachment of the pelvic girdle), and caudal. 



