ANATOMICAL
TERMS:Term
Dorsal
Ventral
Lateral
Anterior
Posterior
Superficial
Proximal
Distal
Meaning
Upper or back surface
Under or belly surface
Side
Toward the front (head) end
Toward the back (tail) end
Near the surface
Close to
Far from
FETAL PIG DISSECTION
SAFETY PRECAUTIONS
Extreme care must be taken when using
dissection instruments, particularly scalpels.
To the extent possible, make cuts away from
your body. The pigs are preserved in a
chemical solution, so wear gloves, goggles
and an apron, and work in a well ventilated
area. If chemicals contact your skin, wash
them off. When you finish, dispose of the
fetal pig in the manner instructed by your
teacher. Clean and disinfect all tools, work
surfaces and your hands.
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Circulatory System
Photo of the heart
with labels of
structures studied
Vital Statistics:
 Name
 Sex
 Length
 Age
Respiratory
System
Photo with labels
of structures
studied
Digestive System
Photo with labels of
structures studied
Excretory
System
Photo with labels
of structures
studied
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PROCEDURE:
PART 1: EXTERNAL ANATOMY
1. Rinse your specimen and place it on its side in the dissecting tray.
2. Measure the specimen from the snout to the base of the tail. Use the graph below to
estimate the gestational age of your specimen.
3. Turn your specimen onto its back. Take a photo of the specimen’s dorsal side to be
included in your assignment.
4. Determine the sex of your specimen by comparing its external reproductive organs to
those in the diagrams below.
5. Record the name, sex, length and age of your pig for use in your assignment.
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PART 2: EXPOSING THE ABDOMINAL ORGANS
1. Place the pig with its dorsal surface on
the tray. Spread out the limbs. Tie a piece of
string to one of the forelimbs near the ankle.
Pass the string under the tray and securely tie
the other forelimb. Repeat the process with
the hind limbs.
2. Select the point just anterior to the
umbilical cord on the specimen’s ventral
surface. Using forceps pinch the skin of the
abdomen along the midventral line and pull it
slightly away from the animal. With your
scissors, make an incision in the skin. The
incision should be just large enough to pass
the point of your scissors through. Now
make a midventral cut (1) ending just
posterior to the midline of the animal. To
avoid damaging the organs as you cut, keep
the tips of the scissors pointing up. Be
careful not to damage the umbilical cord.
3. From the starting point, make a second
incision around the base of the umbilical cord
extending back to just anterior to the anus
(2).
4. Locate the base of the sternum (breast bone), situated in the center of the chest. The ribs are
attached to the sternum. Select a point posterior to the sternum and cut across the ventral surface (3).
The incision should be posterior to the diaphragm, which you will be able to see as a dome-shaped layer
of muscle separating the abdominal and thoracic cavities.
5. Make two final incisions, one on each side of the cuts bordering the umbilical cord and just anterior
to the hind limbs (4). Use T pins to pin back the skin to expose the internal organs of the abdominal
cavity. The T pins should point away from the specimen so they will not interfere with your work.
6. The organs of the abdomen are covered and protected by a membrane called the peritoneum. The
double layered sheets of peritoneum are called mesenteries. Using forceps or a dissecting probe, gently
move the mesenteries aside to reveal the underlying organs.
7. Using the diagram to the right, locate and identify the organs of the abdominal cavity.
8. Using your digital camera, take a photo of your fetal pig’s abdominal cavity.
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PART 3: EXAMINING THE DIGESTIVE SYSTEM
1. Remove the following abdominal organs as carefully and intact as possible. Lay
the organs out on a paper towel so they are displayed in the right sequence.
 Liver
 Small Intestine
 Gall Bladder
 Stomach
 Duodenum
 Pancreas
 Large Intestine
2. Take a photo of the collection of organs displayed on the paper towel to be
included in your assignment.
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PART 4: EXAMINING THE URINARY SYSTEM
1. Remove the following urinary organs as
carefully and intact as possible. Lay the
organs out on a paper towel so they are
displayed in the right sequence.
 Ureters
 Kidneys
 Bladder
2. Take a photo of the collection of organs
displayed on the paper towel to be included
in your assignment.
Kidney
Ureter
Urinary bladder
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PART 4: EXAMINING THE ORGANS OF THE THORACIC CAVITY
Exposing the organs of the thoracic cavity:
1. Locate the base of the sternum (breast bone), situated in the centre of the chest. The
ribs are attached to the sternum. Use this as the starting point for your incision. With
forceps, pinch the skin of the abdomen along the midventral line and draw it slightly
away form the animal. With your scissors, make an incision on the skin. The incision
should be just large enough to pass the point of your scissors through. Now make a
midventral cut (shown as #1 in the diagram below). This cut should extend as far
forward as the hairs near the base of the throat. Be careful not to damage the
underlying body wall as you cut. Remember to keep the tips of your scissors pointing up,
not down, to avoid damaging the internal organs.
2. Next, make two cuts (shown as cuts #2 and #3 in the diagram below) from the
midventral line in the region of the thoracic cavity. Carefully lift the skin and pin it to the
side of the specimen using T pins. The T pins should point away for the specimen so they
will not interfere with your work.
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3. Using a sturdy pair of dissecting
scissors, cut the ribs along the sternum,
and pry them apart to reveal the organs
of the thoracic cavity.
4. Using the forceps or a dissecting probe,
remove the connective tissues and
membranes that surround the lungs and
heart.
Examining the Circulatory System:
6. Carefully remove the heart. Cut from
the bottom to the top to expose all for
chambers as shown in the diagram below
and right. Place the heart on a paper
towel and take a photo to be used for
your assignment.
 Left and right atria
 Left and right ventricles
 Septum
 Tricuspid valve
 Bicuspid valve
Atrium
Ventricle
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EXAMINING THE RESPIRATORY SYSTEM:
5. Carefully remove the trachea, bronchi
and lungs. Ensure that they remain
connected together. Place them on a
paper towel and take a photo to be used
for your assignment.
 Larynx
 Trachea
 Lungs
Epiglottis
Tongue
larynx
Trachea
Esophagus
Lobe of a
Lung
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