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
Check your tray when your arrive - Clean tools and reline tray at the end.
2 forceps, 2 mall probes, 2 dissecting probes, 2 scissors, 8 pins
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
Triceps
Masseter
Serratus ventralis
External oblique
Digastric
Sternomastoid
Biceps
brachii
Sternohyoid