272 DISSECTION OF THE ABDOMEN. 



fascia lumborum. All the fibres are directed to the anterior 

 aponeurosis. 



The aponeu- Its anterior aponeurosis is widest in the centre, and narrowest at 



behTncT 88 S the upper end. Internally it is continued to the linea alba, passing 



rectus, ex - beneath the rectus as low as midway between the umbilicus and the 



lower part, pubis, and in front of the muscle below that spot. Its attachment 



below to the pelvis is nearly the same as the internal oblique ; for 



it is fixed to the front of the pubis, and to the pectineal line for 



Fibres to about an inch. Some of the fibres end on the transversalis fascia, 



fascTa 6rSaliS an ^ are connected beneath Poupart's ligament with a thickened band 



of that fascia which is called the deep crural arch (fig. 97, p. 263). 



Use. Action. The transversalis muscle draws downwards the lower 



ribs, and diminishes the abdominal cavity, compressing the viscera 



and forcing upwards the diaphragm. 



At pelvis Conjoined tendon. The aponeuroses of the internal oblique and 



conjoined transversalis muscles are united near their attachment to the pubis, 



tendon. and give rise to the conjoined tendon. The aponeurosis of the 



internal oblique extends about half an inch along the pectineal line, 



while that of the transversalis reaches an inch along the bony ridge 



and forms the greater part of the conjoined tendon (fig. 102 and fig. 



105, p. 286). 



Posterior The posterior aponeurosis of the transversalis, or the fascia luiu- 



apoueurosis. k orum ( c ^ j s a escr ibed in the deep dissection of the back, and it is 

 sufficient here to state that it consists of three layers : an anterior, 

 attached to the front of the roots of the lumbar transverse process ; a 

 middle, attached to their tips ; and a posterior, attached to the spine 8 

 of the same vertebrce. The transversalis is chiefly continuous with 

 the middle of these layers and only slightly with the others. 

 Relations of Relations. Superficial to the transversalis are the two muscles 

 before examined; and beneath it is the thin transversalis fascia. 

 Its fleshy attachments to the ribs alternate with like processes of 

 the diaphragm ; and the highest slip joins the lower edge of the 

 triangularis sterni muscle. The lower border of the transversalis is 

 fleshy in the outer, but tendinous in the inner half, and is arched 

 above the internal abdominal ring. 

 Expose Dissection, Remove the aponeurotic layer from the rectus muscle 



^ ^ ne r ^ n t side, make a longitudinal incision through the tendinous 

 sheath, and turn it to each side. As the sheath is reflected, its 

 union with three or more tendinous bands across the rectus will 

 have to be cut through ; and near the pubis a small muscle, the 

 pyramidalis, will be exposed. The dissector should leave the nerves 

 entering the outer border of the rectus. 



Leave the On the left side of the body the rectus should not be laid bare 

 left side. below the umbilicus, in order that the special dissection of the parts 



concerned in inguinal hernia may be made on this side. 



Rectus The RECTUS MUSCLE (fig. 102, A) extends along the front of the 



muscle : abdomen from the pelvis to the chest. It is narrowest below, where 



origin from it arises from the pelvis by two tendinous processes : one, the 



internal and smaller, is attached to the front of the symphysis pubis 



