1. Frog Dissection

2. Place Frog in Pan
Place him/her in the dissection pan. The frog should be lying on his dorsal (back) side with his belly facing up.

3. Pin the Frog
To secure the frog for the dissection, pin each of his four limbs to the pan.

4. Begin the First Skin Incision
Once the legs of the frog are securely pinned to the dissection tray you can start your first incision:
Use the forceps to lift the skin midway between the rear legs of the frog.
Using the scalpel, make a small cut through the lifted skin.
This cut should be made in the along the center, or midline, of the frog, bisecting it equally.

5. Continue Skin Incision
Now, using the scissors, continue the incision up the midline all of the way to the frog's neck. Be very careful not to cut too deeply.

6. Finish the First Skin Incision
When your scissors reach the frog's neck, you have cut far enough.

7. Cut Above Front Legs
Using either the scissors or the scalpel, make horizontal incisions through the skin between the front legs.

8. Cut Above Rear Legs
Still using either the scissors or the scalpel, make horizontal incisions through the skin just above the rear legs.

9. Separate Skin & Muscle
Once you have finished the incisions between the front and rear legs of the frog you need to separate the skin flaps from the muscle below. To do this:
Pick up the flap of skin with the forceps, and
Use a scalpel to help separate the skin from the muscle below.

10. Pin Skin Flaps
Once you have finished the incisions between the front and rear legs of the frog you need to separate the skin flaps from the muscle below. To do this: Pick up the flap of skin with the forceps, and Use a scalpel to help separate the skin from the muscle below

11. Begin 1st Muscle Incisions
Begin the incisions in the abdominal muscles in the same way as when cutting through the skin:
Use the forceps to lift the muscle midway between the rear legs of the frog.
Use the scalpel to start the incision in the direction of the chin

12. Continue Muscle Incision
Now, using the scissors, continue the incision up the midline all the way to the frog's neck. Be careful not to cut too deeply. The muscle is thin and you don't want to damage the organs underneath

13. Turn Scissor Blades
This is very important. When you reach a point just below the front legs, turn the scissor blades sideways to cut through the bones in the chest. This should prevent damage to the heart or other internal organs

14. Finish 1st Muscle Incision
When your scissors reach a point just below the frog's neck you have cut far enough.

15. Make 2nd Muscle Incisions
Next, using either the scalpel or scissors, make horizontal incisions through the muscle between the front legs.

16. Second Muscle Incisions
Still using either the scissors or scalpel, make horizontal incisions just above the back legs.

17. Separate Muscle & Organs
To open up the abdominal area you need to pull back the muscle flaps. To do this:
Hold the flaps of the muscle with forceps, and
Use a scalpel to separate the muscle from the tissues below.

18. Pin the Muscle Flaps
Once the muscle flaps have been separated from the underlying tissue, they must be pinned back. This will allow easy access to the frog's internal organs.

19. Open Triangular Flaps
To finish opening up the frog's body cavity, fold back the triangular flaps of skin and muscle which are above the front legs. To do this:
Hold the flap of muscle and skin with the forceps, and
Use a scalpel, if necessary, to help separate the flaps from the underlying tissues.

20. Pin the Triangular Flaps
As above, once the muscle flaps have been separated from the underlying tissue, they must be pinned back to allow access to the body cavity.

21. Liver
You are now at the first layer of the dissection. At this point you will be able to see the entire liver and heart.
The liver is a large, brownish colored organ covering most of the body cavity. In the pictures above it is circled by a yellow border.

22. Heart
The heart is a small triangular shaped organ between the front legs and anterior to the liver. In the pictures above it is circled by a yellow border.

23. Stomach and Intestines
The “J” shaped organ held by the forceps.

24. Gall Bladder
When you raise the liver up you will see a small, greenish sac underneath it. This is the gall bladder. In the pictures above it is circled by a yellow border.

25. Stomach
The stomach is a large, firm, sac-like organ on the left side of the frog. In the pictures above it is circled by a yellow border.

26. Small Intestine
The small intestine is a long, folded, tube-like organ that is posterior to (below) the stomach. It is similar in color to the stomach, but smaller in diameter. In the pictures above it is circled by a yellow border.

27. Lungs
The lungs are at the anterior end of the body cavity on either side of the heart. In a preserved frog, they are small, reddish-pink organs. The frog's left lung is circled in each of the pictures above

28. Ovaries
Found in female frogs only. Locate the ovaries. They are dark organs which may fill most of the frog's body cavity, depending on the time of year that the frog was collected.

29. Frog Fat