PAET THIRD. 



ANATOMY OF THE ABDOMEN AND LOWER 

 EXTREMITY. 



DISSECTION I. 



PARIETES OF THE ABDOMEN. 



A block is to be placed under the lumbar vertebrae, and the abdo- 

 minal muscles made tense by inflating the peritoneal cavity by a blow- 

 pipe introduced through the umbilicus. A longitudinal incision is to be 

 made from the ensiform cartilage to the pubes, penetrating to the ten- 

 dons of the muscles ; the amount of fat to be divided varies so much 

 that great caution is necessary lest the tendons themselves be wound- 

 ed ; when reached they are known by their white and glistening 

 aspect. From just below the umbilicus a second incision is to be car- 

 ried upward and outward to the most dependent part of the margin 

 of the thorax. The precaution above mentioned must also be ob- 

 served in the inner half of this incision, which posteriorly should 

 penetrate to the muscular fibres. The two angular flaps of integu- 

 ment thus formed are to be reflected upward and downward. The dis- 

 sector must keep close to the tendon, cleaning it carefully and slowly 

 from all the cellular tissue and superjacent parts, and, when dissecting 

 the muscular portion, follow the direction of its fibres, freeing them 

 patiently, one by one, from their sheath, being particularly careful at 

 the point of their junction with the broad flat tendon into which they 

 are inserted, not to divide and dissect up the tendon itself, but to keep 

 it intact in its whole extent. Toward the groin more or less of the 

 fascia should be left, in order to observe its relations to the external 

 abdominal ring. The external oblique muscle cannot be exposed 

 posteriorly without turning the subject over upon its face, or at least 

 upon its side. The abdominal muscles are almost invariably disco- 

 lored of a greenish hue ; this is not usually owing to decomposition, 

 but to the effect of sulphuretted hydrogen in the intestinal canal upon 

 the coloring matter of the blood in the muscular tissue. 



The PARIETES OF THE ABDOMEN extend from the median 

 line to the spinal column on each side, and from the ribs 

 above to the pelvis below ; they include three pairs of flat 

 muscles, disposed in layers, and the direction of whose 

 fibres is different ; in front they terminate in extensive apo- 

 neuroses, also disposed in layers, and between them on 



