The skin overlying the linea alba is incised from just below the xyphoid process down to the pubic symphysis.
Be careful not to cut any higher than the xyphoid process. Since the rat has only one pleural cavity, a pneumothorax must be safely avoided.
Since the rat is a loose skinned animal the skin incision, as well as the laparotomy, can be performed with a forceps and scissors. After creating a hole in the abdominal wall, the scissor blade is gently pressed upwards to make sure that no intestines are harmed. Now the linea alba is cut all along its exposed length. Cutting next to it would cause substantially more bleeding.
The small intestine and cecum are taken out of the abdomen and draped in gauze. To keep the intestines moist and viable the gauze is soaked in water.
If the urinary bladder is distended to such an extent that it restricts access to the operating field, it can be punctured and drained with the 2 ml syringe. Retractors are placed in all four corners of the opened abdomen.