ACTION OF THE DIAPHRAGM. 369 



Ordinary Auxiliaries. 



Muscle. Attachments. 



Serratus Posticus Superior Ligarnentum nuchae, spinous processes 



of last cervival and upper two or three 



dorsal vertebrae upper borders of 



second, third, fourth, and fifth ribs 

 just beyond the angles. 



Sterno-mastoideus .. . .Upper part of sternum mastoid pro- 

 cess of temporal bone. 



Extraordinary Auxiliaries. . 



Levator Anguli Scapulae Transverse processes of upper three or 



four cervical vertebrae posterior 

 border of superior angle of the scapula. 



Trapezius (superior portion) Ligamentum nuchae and seventh cervical 



vertebra the upper border of the 



spine of the scapula. 



Pectoralis Minor .Coracoid process of scapula anterior 



surface and upper margins of third, 

 fourth, and fifth ribs near the cartilages. 



Pectoralis Major (inferior portion) Bicipital groove of humerus costal 



cartilages and lower part of the ster- 

 num. 



Serratus Magnus Inner margin of posterior border of scap- 

 ulaexternal surface and upper bor- 

 der of upper eight ribs. 



Action of the Diaphragm. The descriptive and general 

 anatomy of the diaphragm gives a pretty correct idea of its 

 functions in respiration. It arises, anteriorly, from the inner 

 surface of the ensiform cartilage, laterally, from the inner 

 surface of the lower borders of the costal cartilages and the 

 six or seven inferior ribs, passes over the quadratus lumborum 

 by the external arcuate ligament, and the psoas inagnus by 

 the internal arcuate ligament, and has two tendinous slips of 

 origin, called crurae of the diaphragm, from the bodies of the 

 second, third, and fourth lumbar vertebrae and the interverte- 

 bral cartilages on the right side, and the second and third lum- 

 bar vertebrae and the intervertebral cartilages on the left side. 

 From this origin, which extends around the lower circumfer- 

 24 



