412 



DISSECTION OF THE ABDOMEN. 



Fig. 136. 



along the outer half of Poupart's ligament ; along the anterior two-thirds 

 of the crest of the hip bone ; and from the tendon of the transversalis 

 muscle, c, (fascia lumborum) in the interval between that bone and the 

 last rib. The fibres diverge on the abdomen to their destination : The 

 upper are fleshy and ascend to be inserted into the cartilages of the lower 



three ribs, where they join the inter- 

 nal intercostal muscles of the lowest 

 two spaces. The remaining fibres 

 pass obliquely to the aponeurosis. 



The aponeurosis covers the fore 

 part of the abdomen from the pelvis 

 to the chest, and blends with its 

 fellow along the middle line. For 

 the most part it incases the rectus; 

 but midway between the umbilicus 

 and the pubes it is undivided, and 

 lies in front of that muscle. Supe- 

 riorly it is attached to the thorax 

 after the following manner: The 

 stratum superficial to the rectus is 

 fixed to the ninth rib, and blends 

 with the aponeurosis of the external 

 oblique ; and the stratum beneath the 

 muscle joins the cartilages of the 

 eighth and seventh ribs, and the en- 

 siform cartilage. Inferiorly its fibres 

 become more distinct and separate, 

 and are inserted into the front of the 

 pubes, and into the pectineal line for 

 half an inch behind the attachment 

 of Gimbernat's ligament. 



Connections. The internal is cov- 

 ered by the external oblique muscle. 

 It is attached on all sides, except 

 between Poupart's ligament and the 

 pubes where it arches over the cord, 

 and has the cremaster muscle con- 

 tiguous to it. The parts covered by the internal oblique cannot be seen 

 till the muscle is reflected. 



Action Both muscles will depress the ribs ; and will assist in forcing 

 back the viscera of the belly, which have been carried down by the descent 

 of the diaphragm. 



One muscle may incline the body laterally ; and contracting with the 

 external oblique of the other side (the fibres of the two having the same 

 direction) it will rotate the trunk to the same side. 



The CREMASTER MUSCLE (fig. 137, D ) is a fasciculus of fibres, which 

 lies along the lower border of the internal oblique muscle, and is named 

 from suspending the testicle. The muscle has attachments, at the inner 

 and outer sides, similar to those of the internal oblique. Externally it is 

 fleshy, and arises from Poupart's ligament below, ami in part beneath the 

 internal oblique, with which some of the fibres are connected. Internally 

 it is small, arid is inserted by tendon into the front of the pubes, joining 

 the tendon of the internal oblique. . 



INTERNAL OBLIQUE MUSCLE OF THE ABDOMI- 

 NAL WALL. 



A. Internal oblique. 



B. Latissimus dorsi, cut. 



c. Part of the hinder tendon of the transver- 

 salis muscle. 

 D. Poupart's ligament. 

 K External: F. Internal intercostals. 



