Step 4 - Dissection of the Abdominal Wall, Penis and Scrotum
Open the abdominal cavity by cutting through the abdominal muscles medially from above the anterior
superior iliac spine to the umbilicus on either side and then superiorly in the
midline along the lines shown here. The flaps of muscle (A and
B) can then be lifted superiorly toward the costal arch.
Lift the inferior flap to view the umbilical folds
on the deep surface of the abdominal wall. Sometimes,
applying backlighting makes these folds
easier to see. The median umbilical fold is the remnant of the embryologic urachus;
the medial umbilical folds are the remnants of the embryologic umbilical arteries; and
the lateral umbilical folds are formed by the inferior epigastric arteries.
NOTE: The ductus deferens and the round ligament of the uterus pass lateral to the inferior
epigastric arteries as they enter the deep inguinal ring.
Finally, cut this inferior flap in the midline (along the median umbilical fold) and reflect each
flap inferiorly to open the abdominal cavity in preparation for the next dissection.
