24 EQUINE ANATOMY. 



fossae by the petrous portion of the temporal. In the posterior 

 fossa is the foramen magnum, the communication between the 

 spinal and cerebral cavities. 



Contents cerebrum, cerebellum, cranial nerves and vessels. 



The orbital cavity and nasal fossa are described with the special 

 senses of sight and smell. 



The temporal fossce, oval in shape, lie behind the orbit, on the 

 outer cranial wall, bounded within by the parietal ridge, without 

 by the zygomatic process. 



They lodge the temporal muscle, coronoid process and vessels. 



THE HYOID. 



The hyoid bone consists of seven segments, lying below the 

 head, above the larynx and under the tongue, in the inter-maxil- 

 lary space. 



It consists of a body, two thyroid or great cornua, two styloid or 

 lesser cornua, and two styloid bones. 



The body is convex in front, concave behind, with two lateral 

 prolongations, continuous with the thyroid cornua, and an ante- 

 rior appendix, projecting into the muscular structure of the tongue. 



The thyroid or great cornua project backward, articulating with 

 the extremities of the thyroid cartilage. 



The styloid or lesser cornua are small, and articulate below 

 with the body at its junction with the great cornua. It often has 

 a cartilaginous nodule at its inferior extremity, the styloid nucleus. 



The styloid bones are long, flattened on the sides, articulating 

 above with the hyoideal prolongation of the temporal, below with 

 the lesser cornua. They represent the styloid process and stylo- 

 hyoid ligament of man. 



THE STERNUM. 



The sternum forms the inferior boundary of the thoracic cavity, 

 showing on either side articulations for the first eight ribs. It 

 shows an anterior extremity, the cervical prolongation, and a 

 posterior, the abdominal prolongation or xiphoid appendix. 



It is flattened, laterally, in its anterior two-thirds, and from 

 above downwards in its posterior one-third. 

 Articulations, 16. 



With eight anterior ribs on either side. 



