46 THE POCKET ANATOMY 



The corresponding spaces between the rib cartilages are occupied by th* 

 anterior intercostal aponeurosis. 



Intercostales intern! (n) : inner lip of groove on inferior 

 border of rib, extending from angle to sternum(F) inner edge 

 of superior border of rib below (Intercostals). [Probably ele- 

 vate ribs and aid inspiration.] Fibres run downwards and back- 

 wards, but not so obliquely as the external muscles. The inner surface 

 of each intercostal space between the tubercle and angle is occupied by 

 the posterior intercostal aponeurosis. The intercostal vessels and 

 nerve lie between the external and internal muscles. 



Subcostales (10) : inner surface of a rib, near angle(p) 

 inner surface of ist, 2nd, or 3rd ribs below(FT) (Intercostals). 

 [Elevate ribs.] 



Triangularis aterni : side of ensiform appendix and sternum, 

 as high as 3rd intercostal space, posterior surfaces of cartilages 

 of 7th, 6th, and 5th ribs(F) posterior surfaces of 2nd, 3rd, 4th, 

 5th and 6th ribs at junction of bone and cartilage(TF) (Anterior 

 branches of intercostals). [Draws down ribs.] 



Levatores costamm (12) : apex and lower border of trans- 

 verse processes of yth cervical and upper n dorsal vertebrse 

 (T) superior border of rib below, extending from tubercle to 

 angle(F) (Intercostals). [Raise ribs.] 



DIAPHRAGMATIC REGION. 



Diaphragma : posterior surface of ensiform appendix, in- 

 ternal surfaces of lower six costal cartilages(F), ligamenta 

 arcuata (externa et interna) (A). Right crus, from bodies and 

 intervertebral substances of ist, 2nd, 3rd lumbar vertebrae(T). 

 Left crus, from bodies and intervertebral substances of ist 

 and 2nd lumbar vertebrae(T) central tendon (Phrenics). [En- 

 larges vertical diameter of thorax, so aids inspiration.] The 

 ligamentum arcuatum internum arches over psoas, attached to 

 body of ist lumbar vertebra internally and to transverse pro- 

 cess of ist lumbar vertebra externally. The ligamentum arcuatum 

 externum reaches from transverse process of ist lumbar ver- 

 tebra to lower border and apex of last rib, arching over 

 quadratus. 



Openings. AORTIC(F) : between the crura and spine, trans- 

 mits aorta, thoracic duct, and vena azygos major. CESOPHA- 

 GEAL(F) : above and little to left of aortic, transmits 0330- 

 phagus and pneumogastric nerves. CAVAL(T) : in the right 

 leaflet of tendon, transmits vena cava inferior, which is in- 

 separably united to it. In each crus there is a fissure for the 

 three splanchnic nerves, the left one transmitting in addition 



