Aiii THE SKULL. 49 





' d^ semicylindrical transverse piece of bone attached to the 

 caudal margin of the coronoid process. It articulates with the 

 .mandibular fossa of the temporal bone. 



Hyoid Bone. Os hyoideum (Fig. 38 and Fig. 104). — 

 uhe hyoid bone forms the support for the tongue and gives 

 origin to muscles passing to the 

 /./tongue and larynx. It also 

 supports the thyroid cartilage 

 (Fig. 104, 1). 



It consists of a transverse 

 cony bar, the body (Fig. 38, a) 

 id of two COrniia or horns ^7^. jS.-Hyoid Bone, Dorsal View. 



. ;tached to each end of the a, body; i, c, d, e, cranial coiiui; /, 

 •< y caudal cornu; b, ceratohyal; c, epihyal; 



' ^' d, stylohyal; e, tympanohyal; /, tliyro- 



The cranial cornu (lesser hyal- 

 jornu of human anatomy) is the longer (Fig. 38, b-c). Each 

 arises from the cranial face of the body at its lateral end, curves 

 laterad, and then caudodorsad. It consists of four bony pieces 

 ■ . movably united by cartilage. 



; I The terminal piece is the tympanohyal {e) ; it is imbedded 



•in the tympanic bulla just ventrad of the stylomastoid foramen. 



ft is not therefore seen attached to the cornu after the latter 



has been separated from the skull. The other pieces become 



successively shorter toward the body, and are called stylohyal 



d), epihyal {c), and ceratohyal {b). 



The caudal cornua (/) (greater cornua of human anatomy) 

 ::.rise from the ends of the body. Each consists of a single 

 :)iece of bone, the thyrohyal (/), which passes caudolaterad ; 

 its free end is united to a process of the thyroid cartilage (Fig. 

 i04, 1). 



The Skull as a Whole. — In the following description of the 

 ; kull as a whole the mandible, hyoid, and ear-bones are not 

 included. 



The skull forms a bony box which contains the brain and 



is produced craniad into the facial portion which encloses the 



v Spasal cavity and forms the framework of the face. 



i^..3.\ In dorsal view (Fig. 39) the skull presents a smooth con- 



' ';;Vex surface, broadest caudad, with the two zygomatic arches 



