446 APPENDIX. 



IX. The Diaphragm and the Muscles on the Ventral Side of 

 THE Vertebral Column in the Lumbar and Pelvic Regions. 



Remove the ventral and lateral walls of the thorax completely, 

 as far back as. the diaphragm, — leaving only a ring attached to the 

 margin of the diaphragm. Remove the abdominal walls in the same 

 way, as far back as the pubis, leaving the diaphragm in position. 

 Remove the thoracic viscera (the heart and lungs may be preserved 

 for future study). Remove also the abdominal viscera as far back 

 as the beginning of the pelvis, cutting the large intestine where it 

 passes into the pelvis. The dorsal wall of the abdominal cavity 

 should be cleared of fat, blood-vessels, etc., without injury to the 

 crura of the diaphragm. 



1. The diaphragm (p. 151, and Fig. 74). Study by transmitted 

 light, to see the tendons, etc. 



2. The psoas minor (p. 139, and Fig. 162, 9^ p. 398). Find its 

 tendon and separate it from the iliopsoas (Fig. 162, 8) as far craniad 

 as this can be done without tearing the fibres. 



3. The iliopsoas (p. 193, and Fig. 162, 8). Find both portions; 

 isolate them as far as it can be done. 



4. The quadratus lumborum (p. 139). Free the lateral edge of 

 the iliopsoas from the abdominal wall and turn the whole muscle 

 mediad as far as possible. The bundles of the quadratus lumborum 

 will be found beneath it, against the transverse processes of the 

 lumbar vertebra;. 



With a heavy cartilage-knife separate the two innominate bones 

 along the pelvic symphysis. This is easily done if the knife is 

 inserted exactly into the line of junction of the two bones. Divaricate 

 the edges some distance, so as to make a ventral opening into the 

 pelvic cavity. If necessary, part of the innominate bone of one side 

 may be removed to make the opening larger. 



Find the thin sheet of fibres forming the levator ani muscle (Fig. 

 162, 11) at the side of the rectum, attached to the edge of the sym- 

 physis. Carefully free the rectum and urogenital organs from this 

 and remove them as far as the anus, leaving the levator ani intact. 



5. The iliocaudalis (p. 137, antl Fig. 162, ir). 



6. The levator ani (p. 269, and Fig. 162, 11). 



Remove with great care the levator ani and iliocaudalis of one 

 side, by cutting first the attachment to the symphysis and the ilium; 

 turning the muscle mediad, then cutting the attachment to the tail. 

 There are thus exposed on the lateral wall of the thorax the medial 

 surface of the obturator internus, craniad of it the pyriformis, caudad 

 of it the quadratus femoris. Dorsad of these is the abductor caudaa 

 internus. 



7. The abductor caudae internus (p. 137). 



On the ventral surface of the tail are exposed the following: 



8. The flexor cauda; longus (p. 138, and Fig. 162, vS). 



9. The flexor caudce brevis (p. 138, and Fig. 162, 13). 



