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Skinning

Look for the point where latex was injected into the arteries and veins to make them more visible -- in the neck or in the abdomen.
There should be a cut in the skin, or the skin should already be partially removed.

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Use scissors and forceps to cut only the skin, not muscle!
If you see organs, you’ve gone too deep.
The skin should peel easily from the muscle.
The cobweb-like connective tissue that binds skin to muscle is called loose areolar tissue, and it tears easily.

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Remove the skin from all sides of the rat. When finished, it should look like this:

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Neck Muscles

Move the glands out of the way to expose the neck muscles.
Do not remove the glands!

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Masseter

Sternohyoid

Sternomastoid

Spinodeltoid

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Chest Muscles

Spinodeltoid

Pectoralis major (superficialis)

Pectoralis minor (profundus)

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Arm Muscles (Ventral)

Biceps brachii

Triceps brachii

Forearm extensors

Forearm flexors

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Abdominal Muscles

External Oblique

Rectus Abdominis

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Lateral Muscles

Clavotrapezius

Acromiotrapezius

Spinodeltoid

Masseter

Spinotrapezius

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External Oblique

Forearm

Flexors

Forearm Extensors

Spinodeltoid

Latissimus Dorsi

Acromiotrapezius

Spinotrapezius

Cutaneous Maximus

Triceps Brachii

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External Oblique

Forearm

Flexors

Forearm Extensors

Spinodeltoid

Latissimus Dorsi

Acromiotrapezius

Spinotrapezius

Cutaneous Maximus

Triceps Brachii

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Posterior Legs, Dorsal

Semitendinosus

Biceps Femoris

Sartorius

Gluteus Maximus

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Posterior Legs, Ventral

Tensor Fascia Latae

Gracilis

Tibialis Anterior

Gastrocnemius

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Salivary Glands

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Mandibular Glands

Sublingual �Gland

Parotid Gland

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Respiratory System

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Cut through and remove the sternohyoid and sternomastoids to expose the larynx and trachea.
Do not remove the salivary glands!

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Cut through the sternum, taking care not to puncture the diaphragm or damage the heart, arteries, or veins.
Create flaps of bone and muscle by making lateral cuts caudal to the diaphragm.
Open the thoracic cavity and expose the lungs and heart.

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Heart

Larynx

Trachea

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Thymus Gland

Left Lung

Diaphragm

Right Lung:

Anterior Lobe

Middle Lobe

Posterior Lobe

Accessory Lobe

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Digestive System

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Make an “I” shaped cut through the abdominal (muscle) wall and pull the muscle flaps aside. Be sure not to cut through any organs!

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Cecum

Small Intestines (Jejunum)

Large Intestines

Liver

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Reflect the lobes of the liver (do not remove) to expose the stomach, duodenum, and greater omentum.
Pull the jejunum out of the abdominal cavity to see the entire length of the large intestines.

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Note the two connective tissues: the mesentary, which binds the intestines together and has blood vessels, and the greater omentum, which stores fat.

Mesentary

Greater Omentum

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Duodenum

Ascending Colon

Transverse Colon

Spleen

Descending Colon

Rectum

Stomach

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Circulatory System

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The aortic arch has three branches, from left to right: �

brachiocephalic (right subclavian + common carotid)
left common carotid
left subclavian�

In rats, there are two anterior vena cavas -- one left, and one right.

Lead to the internal and external jugular veins.�

There is one posterior vena cava.

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Right Common Carotid

Right Subclavian

Brachiocephalic

Left Common Carotid

Left Subclavian

Left Atrium �(Heart)

Right Atrium �(Heart)

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Left External Jugular

Left Subclavian

Left Anterior Vena Cava

Right Anterior Vena Cava

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Posterior Vena Cava

Left Renal Vein

Abdominal Aorta

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Right Common Iliac Artery

Right Common Iliac Vein

Left External Iliac Vein

Left Internal Iliac Vein

Left Femoral Vein