Setup for Dissection
Preparation
This section explains the steps necessary to prepare your frog for the dissection process.
Step 1: Place Frog in Pan
Rinse the frog with water then place it in the dissection pan. The frog should be lying on its dorsal (back) side with the belly facing up.
Step 2: Pin the Frog
Pin the frog for dissection by securing each of the four limbs to the pan. Place the pins through the hands and feet to secure them to the pan.
Step 3: Begin the First Skin Incision
Once the legs of the frog are securely pinned to the dissection tray begin the first skin incision by using the forceps to lift the skin midway between the rear legs of the frog. Using the scalpel, make a cut along the center, or midline, of the frog, bisecting it equally.
Step 4: Continue the Skin Incision
Continue the skin incision by using the scissors to cut all the way up the frog’s body to the neck. Be very careful not to cut too deeply.
Step 5: Make the Leg Incisions
Still using the scissors, make horizontal incisions just above the rear legs and between the front legs of the frog.
Step 6: Separate the Skin and 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.
Step 7: Pin Skin Flaps
Once the skin flaps have been cut pin them to the dissection tray using several pins.
Step 8: Begin the First Muscle Incisions
This section will describe the procedures for making the incisions through the frog’s abdominal muscles.
Now that the skin has been removed, begin the abdominal muscle incision by using the forceps to lift the muscle midway between the rear legs of the frog. Next, use the scalpel to start the incision in the direction of the chin.
Step 9: Continue the Muscle Incision
Using the scissors, carefully continue the incision up the midline of the frog, but do not cut too deeply as to damage the organs.
Step 10: Turn Scissors Blades
This is very important. When you reach a point just below the front legs, turn the scissors blades sideways to cut through the bones in the chest. This should prevent damage to the heart or other internal organs. When your scissors reach a point just below the frog’s neck you have cut far enough.
Step 11: Make the Second Muscle Incisions
Next, using the scissors, make horizontal incisions through the muscle between both the front legs and above the back legs.
Step 12: Separate Muscle & Organs
To finish opening up the frog’s body cavity, therefore, exposing the abdominal region, use the forceps to hold the muscle flaps while separating the muscle from the tissues below with a scalpel.
Step 13: 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.