]JGAMENTS AND MUSCLES OF THE HORSE. 31 



The Diaphragm 



Consists of 



(a.) A tendinous centre. 



{h.) A fleshy rim. 



(c.) Two crara or pillars. 



The rim is attached to the ensiform cartilage of the 



sternum, and the cartilages of the false ribs (anteriorly), or 



to the rib above the chondro costal joint (posteriorly). 



The right crus (much the largest), is attached to the lumbar 



vertebra?, (blending with the inferior common ligament), 



and joins the tendinous centre. 



The left crus is smaller, and is attached to the first two 



lumbar vertebnv in a similar manner. 



The tendinous centre is composed of white glistening tibres 



which interlace. 

 Foramina of Diaphragm. 



(a.) Hiatus Aorticus.^A notch between the two pillars, giving 



passage to the posterior aorta, vena azygos, and thoracic 



duct. 



{}>.) Foramen De,rtruui.-^it\xs.tQ& slightly to the right of the 

 median plane, about the middle of the tendinous centre. 

 It gives passage to the posterior vena cava, which is ad- 

 herent to its margin. 



(c ) Foramen Sinistrum.-^h:^ is a slit in the fibres of the right 

 crus, a little to the left of the median plane. Through it 

 pass the oesophagus, oesophageal branches of the pneurao- 

 gastric nerve, and the pleural artery. 



The sympathetic and splanchnic nerves pass to the abdomen 

 above the crura, and underneath the psoas parvus muscles. 



Action of Diaphragm. -It is the principal muscle of inspiration, 

 increasing the antero-posterior diameter of the Thorax. 



COCCYGEAL REGIOIS. 



1. Erector coccygis. 3. Curvator coccygis. ^ 



'2. Depressor coceijgis. 4. Compressor coccygh. 



