SURGICAL ANATOMY OF THE ABDOMEN 13 



pancreas. The crook or arch looks forwards, and in 

 the concavity of the curve on its inside the small in- 

 testine opens and the colon begins. The inferior ex- 

 tremity is placed within the double colon at its sternal 

 curve, the apex resting on the ensiform cartilage of the 

 sternum ; at least, this is its usual position. The colon is 

 divided into two portions, the single and double ; it is 

 about 12 feet in length. For convenience of description 

 the double colon is divided into four parts ; commencing 

 from the crook of the caecum it proceeds forwards and 

 downwards, passing beneath the right kidney (having the 

 pancreas between it and that organ) to the diaphragm, 

 and, bending to the left, forms its suprasternal flexure ; the 

 second portion is continued from here, running backwards 

 and upwards into the left flank, turning inwards opposite 

 the pelvis and close up against the spine to form the pelvic 

 HexHve ; now follows the third portion, running forwards 

 above the second and attached to it by peritoneum : when 

 it reaches the diaphragm it makes a curve to the right, 

 the diaphyagmatic flexure, followed by the fourth portion, 

 which is attached by peritoneum to the first, and reaches 

 posteriorly to the base of the caecum, where it terminates 

 in the single colon. This crosses to the left side beneath 

 the first lumbar and last dorsal vertebrae, being attached 

 by peritoneum to the crura of the diaphragm and the 

 mesenteric vessels. The double colon at its origin is 

 very small, but it quickly enlarges, and at the supra- 

 sternal flexure is of considerable size ; at its pelvic curve 

 it is greatly reduced in volume, but at the diaphragmatic 

 flexure it again enlarges, and close to where it terminates 

 in the single colon attains its largest size, and then suddenly 

 contracts to form the single colon. These differences in 

 the volume of the colon are of direct practical interest. 

 The pelvic curvature and the single colon are the most 



