Procedure: Organ weights and tibia length

1. Mice are euthanized in the CO₂ chamber.
2. Body weight is measured.
3. The abdomen of each mouse is doused with ethanol to avoid hair contamination.
4. The mouse is pinned down on a cork board ventral-side-up.
5. The fur is opened above the symphysis with a small incision; a double-Y is cut through the skin without disturbing the underlying abdominal muscles; the Y-incision is extended to the mandibular bone and toward the paws.
6. Skin flaps are pinned back onto the board, without disturbing abdominal muscles.
7. The abdominal wall is opened with an incision above the pelvis in a T-manner to the ribcage and sternal bone.
8. The abdominal cavity is opened by folding the muscles back.
9. Organs are dissected:
   1. Heart: dissect from aortic root right above the atria; dip the heart onto tissue to remove as much blood from the atria and chambers as possible.
   2. Liver: dissect from the stomach, diaphragm ligaments, and vessels at the hilus.
   3. Spleen: dissect carefully from the pancreas; remove vessels at the hilus.
10. Organs are weighed.
11. Tibia length is measured by removing the pin from the left hindpaw, flexing the limb and measuring the length with caliper from the patella to the ankle.