QUESTIONS AND ANSWERS 61 



Insertion : The transverse processes of the lumbar vertebrae and 

 the outer surfaces of the fifteen or sixteen last ribs. 



Action : Extends the vertebral column and pulls the ribs forward 

 in expiration. 



Give the origin, insertion and action of the longus colli muscle. 



Origin: Posterior portion arises from the inferior face of the 

 bodies of the first six dorsal vertebrae. The middle portion, from 

 the transverse processes of the last six cervical vertebrae. The an- 

 terior portion, from the anterior three or four fasciculi of the 

 middle portion. 



Insertion: The posterior portion is inserted on the tubercle of 

 the sixth cervical vertebra. The middle portion, on the inferior 

 ridge of the bodies of the first six cervical vertebrae. The anterior 

 portion, on the inferior tubercle of the atlas. 



Action: Flexes the neck. 



Give the origin, insertion and action of the serratus magnus. 

 Origin : The external surface of the first eight ribs. 

 Insertion : The anterior and posterior triangular surfaces of the 

 scapula and the subscapularis. 



Action : Supports the body as a girdle, or depresses the scapula. 



Describe the diaphragm. What important structures pass through the 

 diaphragm? 



The diaphragm is the muscular partition between the thoracic 

 and abdominal cavities. 



Originates by right and left pillars from the lumbar vertebrae 

 and is confounded with the inferior common ligament of the spine ; 

 also from the xiphoid appendage of the sternum, and the anterior 

 extremities of the last twelve ribs. 



Insertion: Phrenic centre, dividing into right and left leaflets. 



The diaphragm is related anteriorly with the pleura and lungs ; 

 posteriorly, with the peritoneum, stomach, liver, colon and spleen. 



The aorta, thoracic duct, vena cava and oesophagus pass through 

 the diaphragm. 



How does the diaphragm of the ox differ from that of the horse? Of 

 what surgical importance is this difference? 

 The attachments of the muscular portion are much farther dis- 

 tant from the cartilaginous circle than in the horse. 



This arrangement permits puncture of the rumen through the 

 last intercostal space, whereas a puncture at this point in the horse 

 would enter the thoracic cavity. 



