MYOLOGY 91 



Attachments. By a delicate aponeurotic membrane, from the sides 

 of all the true dorsal ribs, from the posterior border of the last ver- 

 tebral rib and the adjoining margins of the pelvis, and from the 

 entire posterior surface of the inferior border of the post-pubic 

 element of the pelvis; by aponeurosis, blending with the fascia to- 

 ward the root of the tail and lower part of the abdomen; and by 

 aponeurosis to the sides of the sternum, to the under part of the 

 pectoralis major muscle, and to the zyphoid prolongation. Also 

 by aponeurosis it meets its fellow from the opposite side, at the 

 linea alba. 



FIG. 22. The abdominal muscles of a hen. Right side, i, Obliquus ab- 

 dominis externus. 2, Obliquus abdominis internus. 3, Peritoneum covering 

 intestines. 4, Peritoneum covering the gizzard. 5, The lungs (note how small 

 they are from a relative standpoint). 6, The great sciatic or ischiadic nerve. 

 7, Lumbar nerves. 8, Kidney. 9, Brachial plexus. 10, Pericardium of the 

 base of the heart, n, Anterior vena cava. 12, Oil gland. 13, Showing a 

 sacculation of the abdominal muscles. There is no tunica abdominalis in the 

 fowl. 



Obliquus Abdominis Internus (Fig. 22, No. 2). Location. Just 

 internal with regard to the external oblique. 



Attachments. By aponeurosis, from the posterior third of the 

 post-pubic element of the pelvis; by muscular fibers, from the bal- 

 ance of the bone; and by a few fibers, from the iliac border posterior 

 to the acetabulum. Anteriorly, these fibers are inserted to the 

 entire posterior margin of the last vertebral rib, and into the pleura- 

 pophysial head of the last costal rib. 



Rectus Abdominis (Fig. 13, No. 10 and Fig. 23, No. i). Location. 

 The inferior median abdominal wall. 



