590 



Anatomy, Physiology, and Pathology of the 



part of the neck upon the front of the chest when the ani- 

 mal's head is directed towards his side. The posterior portion 

 of the sternum in both animals presents fewer differences for ob- 

 servation, beino: terminated by a cartilage called the ensiform, 

 lettered c, fig. 1 1, and Z>, fig. 12. The attachments of the ribs 



Fiff. 12. 



Lateral view of the sternum of the horse, showing its keel-like shape. 

 a. The cariniforra cartilage. h. The ensiform cartilage. 



13. 



Portions of the ribs and their car- 

 tilages of the horse and ox. 



a. 1 ib or horse, showing d, its in- 

 dented u nion with the cartilage. 

 h. Rib of ox. c. Its synovial 

 articulation with the cartilage. 



to their cartilages also varies considerably, as seen in the sub- 

 joined sketch, fig. 13, where a represents a portion of the rib of 

 the horse, with its cartilage, and h the 

 same parts of the ox. In the former the 

 lower end of the rib is received into a cup- 

 like cavity in the upper part of the car- 

 tilaae ; a union which is further strensfth- 

 ened by indentations of their edges, locking 

 into each other, but greatly limiting the 

 extent of tlie motion between them : d^ 

 fig. 13. In the latter, however, we meet 

 with a true synovial articulation in this 

 place, marked c, in figs. 9 and 13. The 

 nature of this attachment was several years 

 since pointed out by Mr, Varnell, Demonstrator of Anatomy in 

 the Royal Veterinary College. Besides the facilities for motion 

 hereby obtained, the cartilages at their lower extremities are united 

 to the sternum, as in the horse, by synovial joints : see d, fig. 9. 



Having described the mechanical arrangements of the walls of 

 the thoracic cavity, we proceed to speak of the principal organs 

 which are concerned in respiration : they are the larynx, the wind- 

 pipe with its branches, and the lungs. At the upper part of the 

 windpipe, which, as its name implies, is the conduit of the air to 

 the lungs, we observe a peculiarly constructed organ, called the 

 larynx. It differs in many particulars in nearly every variety of 

 animal, and is more complicated in man than in any of the in- 

 ferior creatures. The larynx discharges a double office, being 

 the organ of voice, as well as the conduit for the air in breathing ; 

 and in proportion as the voice is incapable of modification, so do 

 we find simplicity in its structure. It presents the same general 



