642 A MANUAL OF ANATOMV 



passing between the anterior superior iliac spine and the pubic 

 spine. 



The internal abdominal ring is situated midway between the 

 symphysis pubis and the anterior superior iUac spine, and | inch 

 above Poupart's Hgament. 



The inguinal canal extends obliquely downwards, forwards, and 

 inwards from the internal to the external abdominal ring, and is 

 situated immediately above the inner half of Poupart's ligament. 



Topography of Arteries, Triangles, and Iliac Fossae. — ^The bifur- 

 cation of the aorta into right and left common iliac arteries usually 

 takes place opposite the centre of the body of the fourth lumbar 

 vertebra, a finger's breadth to the left of the middle line. The 

 position of the bifurcation is indicated in one of two ways : (i) a 

 point fully i inch below the umbilicus and a finger's breadth to the 

 left of the linea alba pretty nearly corresponds with the point of 

 bifurcation ; (2) a more definite guide is a point in the line which 

 connects the highest parts of the iliac crests a finger's breadth to 

 the left of where it intersects the linea alba. 



The common and external iliac arteries are indicated by a line 

 drawn from a point midway between the anterior superior iliac 

 spine and the symphysis pubis to the point corresponding to the 

 bifurcation of the aorta. This line should be slightly curved, with 

 the convexity directed outwards. Its upper 2 inches indicate the 

 course of the common iliac artery, and the remainder represents 

 the external iliac. 



The deep epigastric artery, in its first or oblique part, is indicated 

 by a line drawn from the inner border of the internal abdominal 

 ring to the outer border of the rectus abdominis at a point midway 

 between the upper border of the symphysis pubis and the umbilicus. 

 The subsequent course of the vessel is represented by a line corre- 

 sponding to the centre of the rectus abdominis, and reaching to a 

 point about 2 inches above the umbilicus. This latter line is about 

 i| inches distant from the linea alba. 



The triangle of Hesselbach is situated on the inner side of the 

 first or oblique part of the deep epigastric artery, and above the 

 inner half of Poupart's ligament. 



The triangle of Petit is situated immediately above the centre 

 of the iliac crest. In this region a lumbar hernia may protrude, 

 and a lumbar abscess may come to the surface at this point. 



The right iliac fossa contains the terminal part of the ileum, the 

 caecum, the ileo-csecal valve, and the vermiform appendix in part. 



The left iliac fossa contains the iliac colon. 



McBurney's point is situated in the right spino- umbilical line 

 between i| and 2 inches from the anterior superior iliac spine. 

 According to McBurney it corresponds very accurately in the living 

 subject to the base of the vermiform appendix. Practically it 

 coincides with the centre of the right iliac fossa. 



Monro's point is situated at the centre of the spino-umbilical 

 line. Its distance from the anterior superior iliac spine a 2-6 inches. 



