What are the name and locations of the specific abdominal muscles used within evacuating?

If you have a interconnect with a diagram that would be even better. The individual muscles under voluntary control pertinent to this function are the puborectalis and the external anal sphincter and they mantain fecal continence. You may be refering to what muscles would you use to force evacuation if you are constipated. All the muscles of the abdominal wall can be contracted surrounded by order to lift up the intraabdominal pressure and facilitate defecation.
I suggest you look at Grey's Anatomy. it's all surrounded by there within disgusting detail.
I'm not sure there are any specific muscles. Peristalsis (spellling may not be correct) surrounded by the intestine helps "move things along" as it be. I suppose any muscles in the belly might help include a bit of squeeze.