THE SKELETON. 67 



11. How do you distinguish the caudal from the cephalic aspect of 

 any vertebra? 



12. Draw ventral aspect of sacrum and label all features. 



13. Give the two features distinguishing the caudal vertebrae from 

 all others. 



14. Note the size and direction of the spinous process throughout 

 the column. 



15. Describe the variation in number of the different groups of ver- 

 tebrae in other mammals. 



16. Draw lateral aspect of sternum and label all features. 



17. Describe the attachment of ribs to sternum. 



18. What features common to all the ribs? 



19. Name ribs having a tubercle. 



20. Draw first rib and label all features. 



21. Draw cephalic aspect of ninth rib and label all features. 



22. How do you distinguish a false rib from a true rib? 



23. What features mark the caudal aspect of a rib? 



24. Make a drawing showing the articulation of a rib with the spinal 

 column and label all parts. 



25. How do ribs vary as to number in mammals? 



THE THORACIC LIMB. 



The thoracic or fore-limb of the cat is composed of a 

 scapula, clavicle, humerus, ulna, radius, seven carpals, 

 five metacarpals, and fourteen phalanges (Fig. 20). The 

 scapula and clavicle form the shoulder girdle. 



The scapula, commonly called the shoulder-blade (Fig. 

 30), is not articulated with the bones of the trunk, but 

 is held in position by the serratus magnus, levator anguli 

 scapulae, and other less important muscles. It articulates 

 with the head of the humerus by the glenoid cavity. It 

 presents three well-marked borders: the cephalic or an- 

 terior, the vertebral, and the axillary adjacent to the 

 vertebrae on the side near the axilla or armpit. The 

 outer surface of this bone is divided by a strong spine 

 into two nearly equal fossae, the cephalic of which is the 

 supraspinous, and the caudal one the infraspinous, fossa. 



