General Procedures and Dissection Graded Lab Procedures include: –The maintenance of tray and tools which includes cleaning at the end of each lab period. –The removal of any hair and/or tissue from the tables, sink, and drain trap. –Following dissection directions. NO mutilation Dissection grades by quizzes and practical exams.

Tools 2 forceps, 2 mall probes, 2 dissecting probes, 2 scissors, 8 pins Check your tray when your arrive - Clean tools and reline tray at the end.

External Anatomy Use the lab handout illustrations to identify the external structures on the rat. Once you have located major external structures and determined the gender of your rat you are ready to begin the skinning process.

Skinning the Rat Place rat in tray dorsal side up.

Use the point of the scissors to make an incision on the top of the head between the eyes.

Insert the mall probe and lift the skin away from the head.

Cut the lifted skin. Continue to lift and cut along the backbone.

Continue this incision until you reach the scaly top of the tail

Use the mall probe to lift the skin along the abdomen, on the left side of the rat. You will need to cut or break connective tissue holding the skin. Careful!!! The abdominal wall is thin.

Starting with the mid-dorsal incision, cut laterally behind the ear. Continue the cut around and across the ventral neck area.

You should now be able to pull the skin from around the forelimb.

Completely expose the forelimb.

Repeat the procedure with the hindlimb, by making a lateral cut posterior to the leg but anterior to the genital area.

You should now be able to pull the flap of skin from the rat’s body, Remember to be very careful along the thin abdominal wall.

Lateral View of skinned Rat

Use the mall probe to loosen the skin covering the neck and chest areas. Cut this skin away.

Lift and remove the skin from the head between the eye and ear, and around to the ventral side. Keep the ear in place.

The ear is intact

Identification of Muscles At this point all areas where muscles you will study are located, have been skinned. These areas must be cleaned before specific muscle can be distinguished. Use forceps to remove superficial fatty tissue that covers the surface of most muscles. Separate muscles by observing the direction of the fibers and comparing to illustrations.

Lateral View of the Muscles you will learn

Ventral view of the muscles you will learn.

Gluteus Superficialis Biceps femoris

Cervical trapezius Latissiumus dorsi

MasseterSerratus ventralis Triceps

External oblique

Digastric Sternomastoid Biceps brachii Sternohyoid