124 



TOPOGRAPHIC AND APPLIED ANATOMY. 



FlG. 56. The inferior half of the anterior abdominal wall as seen from within. The pelvis is shown in frontal 

 section. The greater portion of the peritoneum has been left intact, but portions of it have been removed upon the 

 right from the internal abdominal ring, upon the left from the epigastric vessels, the lateral umbilical ligament and the 

 vas deferens, and in the middle line from the median umbilical ligament. 



FIG. 57. In the left iliac fossa the layers of the abdominal wall are shown, the dissection exposing the sigmoid colon. 

 The recti muscles are divided and the urinary bladder has been made visible above the symphysis without injuring the 

 peritoneum. Upon the right side there is an internal inguinal hernia. 



contain the inferior (deep) epigastric artery and veins. The vas deferens may also be seen beneath 

 the peritoneum and palpated as a hard cord; it is situated to the outer side of the epigastric fold. 

 In this situation it leaves the inguinal canal to pass into the true pelvis behind the bladder. This 



Plica umbili- 



calis lateralis 



Sac of femoral 



hernia 



Symphysis 



Plica umbili- 



calis media 



Cavity of 

 bladder 

 Bladder 



Plica epigas- 

 trica 



Lateral inguinal 

 fossa 



External ob- 

 lique muscle 



Internal ob- 

 lique muscle 



Transversalis 

 muscle 



FIG. 58. The inferior half of the anterior abdominal wall with the hernial regions as seen from within and above. 

 At the site of the femoral ring is the sac of a femoral hernia. The interior inguinal fossa is limited internally by 

 a sharply bordered fold (falx inguinalis), which belongs to the transversalis abdominis muscle. (Frozen formalin pre- 

 paration.) 



orifice of the inguinal canal is known as the internal abdominal ring in contradistinction to the 

 external orifice, which is known as the external abdominal ring. At the internal ring the sper- 

 matic vessels (the spermatic artery from the abdominal aorta and the spermatic veins) also dis- 

 appear in company with the vas deferens. The peritoneum closes this internal abdominal ring 

 and forms the external inguinal fossa (fovea inguinalis lateralis), which is situated to the outer 

 side of the deep epigastric artery. While this fossa corresponds to the abdominal orifice of the 

 inguinal canal, the middle inguinal fossa (fovea inguinalis medialis), situated between the plica 

 epigastrica and the plica umbilicalis lateralis, lies directly beneath the external opening of the 

 inguinal canal. Still further to the inner side is the fovea supravesicalis, situated between the 



