Methods 3% trypanblau was intravenously injected into experimental rabbits.The subcutaneous loose connective tissue of abdominal wall was removed for stretching,staining and observed under microscope.
医学百科 The Medicine Book (Big Ideas Simply Explained)
In 1910, Swedish surgeon Hans Jacobeus described the first use of diagnostic laparoscopy, performed by inserting a cystoscope through the patient's abdominal wall.
And if you were tiny and you followed that tunnel, you would find that it was attached to the connective tissue in the abdominal wall that holds our organs in place.