194 



UlAi'JIKAG-M. 



cess of the first lumbar vertebra, and by the other to the body of the 

 second. 



Fig. so * 



The tendinous centre of the diaphragm is shaped like a trefoil leaf, 

 of which the central leaflet points to the ensiform cartilage, and is 

 the largest ; the lateral leaflets, right and left, occupy the correspond- 

 ing portions of the muscle ; the right being the larger and more 

 rounded, and the left smaller and lengthened in its form. 



Between the sides of the ensiform cartilage and the cartilages of 

 the adjoining ribs, is a small triangular space where the muscular 

 fibres of the diaphragm are deficient. This space is closed only by 

 peritoneum on the side of the abdomen, and by pleura within the 

 chest. It is therefore a weak point, and a portion of the contents of 

 the abdomen might, by violent exertion, be forced through it, pro- 

 ducing phrenic, or diaphragmatic hernia. 



The lesser muscle of the diaphragm takes its origin from the bodies 



* The under or abdominal side of the diaphragm. 1, 2, 3. The greater muscle; the 

 figure 1 rests upon the central leaflet of the tendinous centre; the number 2 on the left 

 or smallest leaflet ; and number 3 on the right leaflet. 4. The thin fasciculus which 

 arises from the ensiform cartilage ; a small triangular space is left on either side of this 

 fasciculus, which is closed only by the serous membranes of the abdomen and chest. 

 5. The ligamentum arcuatum externum of the left side. 6. The ligarnentum arcuatum 

 internum. 7. A small arched opening occasionally found, through which the lesser 

 splanchnic nerve passes. 8. The right or larger tendon of the lesser muscle ; a muscu- 

 lar fasciculus from this tendon curves to the left side of the greater muscle between the 

 oesophageal and aortic openings. 9. The fourth lumbar vertebra. 10. The left or 

 shorter tendon of the lesser muscle. 11. The aortic opening occupied by the aorta, 

 which is cut short off. 12. A portion of the oesophagus issuing through the cesopha- 

 geal opening. 13. The opening for the inferior vena cava, in the tendinous centre of 

 the diaphragm. 14. The psoas magnus muscle passing beneath the ligamentum 

 arcuatum internum : it has been removed on the opposite side to show the arch more 

 distinctly. 15. The quadratus lumborum passing beneath the ligamentum arcuatum 

 externum ; this muscle has also been removed on the left side. 



