INTERNAL OBLIQUE MUSCLE. 411 



part of the aponeurosis towards the thigh, as in fig. 140. For this pur- 

 pose an incision is to be carried through the aponeurosis from the front of 

 the iliac crest to about three inches from the linea alba ; and the tendon 

 is to be detached from the subjacent parts with the handle of the scalpel. 

 When the aponeurosis cannot be separated farther from the tendons be- 

 neath, near the linea alba, it is to be cut in the direction of a vertical line 

 to the symphysis pubis. 



After the triangular piece of the aponeurosis has been thrown towards 



the thigh, the spermatic cord is to be dislodged from the surface of Pou- 



/ part's ligament, to see the insertion of this band into the pubes, and to lay 



bare the fibres (triangular ligament) which ascend therefrom to the linea 



alba. 



Potipart's ligament (fig. 136, D ) is the lower border of the aponeurosis 

 of the external oblique, which intervenes between the front of the crista 

 ilii and the pubes. Externally it is round and cord-like, and is attached 

 to the anterior superior iliac spine. Internally it widens as it approaches 

 the pubes (fig. 135, D ), and is inserted into the pubic spine and the pec- 

 tineal line of the hip-bone for about three-quarters of an inch, forming a 

 triangular -looking piece with its base directed outwards, which is named 

 Gimbernat's ligament. 



Poupart's ligament is not straight between its outer and inner attach- 

 ments, but is curved downwards to the thigh ; and it retains this position 

 as long as the fascia lata remains uncut. Its outer half is oblique, and is 

 firmly united with the. subjacent iliac fascia ; along the line of union of 

 the two, the other lateral muscles of the abdominal wall are attached. 

 Its inner half is placed over the vessels passing from the abdomen to the 

 thigh. 



Triangular ligament. From the insertion of Gimbernat's ligament 

 into the pectineal line, some fibres are directed upwards and inwards to 

 the linea alba, where they blend with the other tendons. As the fibres 

 ascend, they diverge and form a thin band, to which the above name has 

 been given. 



Dissection. The upper part of the external oblique is now to be taken 

 away, on both sides of the body, to see the parts underneath. The muscle 

 may be detached by carrying the scalpel through the digitations on the 

 ribs back to the free border, and then through the insertion into the crista 

 ilii. It may be thrown forwards as far as practicable, after the nerves 

 crossing the iliac crest are dissected out ; but in raising it care must be 

 taken not to detach the rectus muscle from the ribs above, nor to cut 

 through the tendon of the internal oblique at the upper part. By the 

 removal of the fatty tissue the underlying internal oblique muscle, with 

 some nerves on its surface below, will be prepared. 



At the lower border of the internal oblique the cremaster muscle on the 

 cord is to be defined (fig. 137) : it is about as wide as the little finger, and 

 consists of fleshy loops which issue through the external abdominal ring. 

 Its inner attachment is tendinous, and is easily taken away. 



Parts covered by external oblique (fig. 136). Beneath the external, is 

 the internal oblique muscle, with the ribs and the intercostal muscle?. At 

 the lower part of the abdomen the muscle conceals the spermatic cord, and 

 the branches of the lumbar plexus in the abdominal wall. 



The INTERNAL OBLIQUE MUSCLE (fig. 136, A ) is fleshy below and apo- 

 neurotic above, just the reverse of the preceding ; and its fibres (except the 

 lowest) ascend across those of the external oblique. The muscle arises 



