ABDOMEN. 



THE ABDOMINAL WALLS. 



Dissection. Locate on the cadaver (i) the ensiform, or metastcrnum ; (2) the 

 sympliysis pubis ; (3) the spine of the pnbcs ; (4) the crest of the pubes ; (5) the 

 crest of the ilium ; (6) the anterior superior iliac spine ; (7) the loiver eight ribs ; 

 (8) the umbilicus; (9) Pouparf 's ligament ; (10) the mid-line of the abdomen. 



The abdominal walls include (i) skin ; (2) superficial fascia; (3) panniculus 

 adiposus ; (4) deep fascia ; (5) the external or descending oblique muscle ; (6) the 

 internal or ascending oblique muscle ; (7) the transversalis muscle ; (8) the rectus 

 abdominis ; (9) the pyramidalis ; (10) the sheath of the rectus; (i i) the trans- 

 versalis fascia; (12) the linea alba; (13) the lineae transversae ; (14) the linese 

 semilunares ; (i 5) peritoneum. 



1 . Define panniculus adiposus. 



The great mass of fat in the upper strata of superficial fascia is thus desig- 

 nated. It is of variable thickness. In it are found the cutaneous vessels and 

 nerves to the skin covering the abdomen. 



2. What can you say of the deep fascia ? 



It is beyond doubt the same as the aponeurosis of the external oblique 

 muscle. The thin fascia described by some authors is not continuous with the 

 fascia lata, nor has it attachments to bone ; hence it must be the deep layer of 

 the superficial fascia. The aponeurosis of the external oblique muscle is continu- 

 ous with the fascia lata ; hence it must represent the deep fascia. 



3. Define linea alba. 



It is in the mid-line, extending from the ensiform cartilage to the symphysis 

 pubis. It is the place where the muscles of the two sides of the abdomen meet. 



4. Hoiv is the sheath of the rectus formed f 



By a delamination or splitting of the aponeurosis ofthe internal oblique muscle. 

 In front of the muscle, then, is the entire thickness of the aponeurosis of the 

 external oblique, and half of the thickness of the internal oblique ; behind the 

 muscle is the entire thickness of the transversalis, and half of the thickness of 

 the aponeurosis of the internal oblique. 



5 . Does the muscle extend through the sheath from end to end in this manner ? 

 No ; it perforates the posterior wall of its sheath midway between the 



umbilicus and the pubic crest, thus leaving, from this point down to the pubic 

 crest, the three aponeuroses all in front of the muscle. 



6. By what name is the lower margin of the posterior part of the sheath of the 

 rectus known ? 



It is called the semilunar fold of Douglas. 



Preparation and Incisions. Make a circular incision through the skin, three 

 inches in diameter, around the umbilicus as the central point. Begin at the cir- 

 cumference and dissect the skin toward the umbilicus for about one inch all 

 around. Now, with a small pair of scissors puncture into the peritoneal cavity 

 through the center of the umbilicus ; insert a tube and inflate the cavity to its 



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