DIAPHRAGMATIC REGION. 209^ 



down the central line of the tendinous portion, and gradually 

 blend with its fibres. Near the centre- of the diaphragm, and a 

 little to the right, is a large opening, the foramen dextrum^ 

 through which passes the posterior vena cava. Between the 

 pillars superiorly is a second opening, the hiatus aorticus, through 

 which pass the posterior aorta, vena azygos, and thoracic duct. 

 Below this, the right crus forms towards the left a third opening, 

 the foramen sinistrum, for the passage of the oesophagus and 

 pneumogastric nerves, accompanied by the pleural artery. There 



Fig. 77. 



The diaphragm, and superficial muscles of the internal femoral region— viewed from belowr 

 A, The diaphragm ; a a, The tendinous centre ; a' a'. The fleshy periphery; a" a"i The crura; 

 a'", The hiatus aorticus ; a"". The foramen sinistrum ; a""'. The foramen dextrum ; &, The sar- 

 torias ; c, The gracilis. 



are thus three openings — the hiatus aorticus above, the foramen 

 sinistrum in the middle, and the foramen dextrum below. 

 Certain of the sublumbar muscles originate partly in the thorax, 

 and the diaphragm forms arches which allow their passage, and 

 that of the sjonpathetic and splanchnic nerves ; these arches are 

 bouiided by ligaments, the ligamenta arcuata ; outside the arches, 

 the diaphragm is attached to the last rib by a broad fold ot 

 elastic tissue. 



Relation. — Anteriorly with the pleura, which covers Doth it 



p 



