136 EQUINE ANATOMY. 



the last dorsal vertebrae from the tenth, the lumbar 

 vertebrae, posterior border and external face of the 

 nine last ribs. Action : Expiratory. 



5. Ilio-spinalis. — Synonyms. Longissimus dorsi, 

 (P). Attachments : The lumbar border, external an- 

 gle and internal face of the ilium, sacro-iliac ligament, 

 sacrum, spinous processes of all the lumbar, dorsal, and 

 last four cervical vertebrae, articular facets of the 

 lumbar vertebrae, the transverse processes of all the 

 dorsal and last four cervical vertebrae, costiform pro- 

 cesses of the lumbar vertebrae, external surface of the 

 fifteen or sixteen last ribs. Action : Extensor of the 

 vertebral column ; may act as an expirator. 



6. Common intercostal. — Synonyms. Trachelo- 

 costalis, (G). Transversal costarum, (P.) Attach- 

 ments : The external face of the ribs, transverse pro- 

 cess of the last cervical vertebrae. Action : Depresses 

 the ribs. 



T. Transverse spinous of the back and loins. — 

 Synonyms. Transverso-spinous, (G). Spinalis and 

 semi-spinalis dorsi, (P). Attachments: The lateral 

 border of the sacrum, the articular processes of the 

 lumbar and transverse processes of the dorsal vertebrae, 

 spinous processes of the sacral, lumbar, dorsal and last 

 cervical vertebrae. Action : Extensor of the spine. 



Costal Region.— Fifty-four pairs. 



