34 



THE HORSE IN HEALTH AND DISEASE 



BONES OF THE AXIAL SKELETON 



The nxiol skeletaii consists of the liead, verteljral eolumii, and 

 thorax. Each of these parts is iniiiortant enougli to tleserve special 

 study. 



The head or skull is composed of 34 bones (including the small 

 bones in the ears). They are divided into the cranial bones, which 

 enclose the brain and the essential (jrgans of hearing, and the 

 facial 6o/(f.s-, which include all the other bones of the head. 



Occipital Parietal 



Squamous temporal 



Fig. 3. — Skull (right view): 1, 2, Occipital bone; 3, 4, 5, 6, 7, 8, 9, processes 

 of temporal bone; 10, 11, 12, parts of frontal bone; 13, 14, 15, lacrimal bone; 

 16, malar bone; 17, tuberosity of nfaxilla; IS, facial crest; 19, infra-orbital 

 forameifl*%3, nasomaxillary notch; 21, body of premaxilla; 21', nasal proce.ss 

 of same; 22, 23, 24, 2.5, 26, 27, 28, 29, mandible; 30, interdental .space; 31, 

 inci.sor teeth; 32, canine teeth; 33, hyoidbone. (Sisson, Anatomy of Domestic 

 Animals.) 



Most of the bones of the skull are flat Iwncs (Fig. 3). There are 

 only two freely movable joints between the bones of the head, 

 the articulation of the lower jaw and that between the hyoid bone 

 and the base of the skull. All other unions are by connective 

 tissue and are immovable. 



The bones of the cranium are the occipital, sphenoid, ethmoid, 



