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CWD Testing

Procedure for Removal of the Brain Stem & Cerebellum for CWD Testing in Cervine Animals

Step 1 - Remove the head from the animal at the atlanto-occipital joint. This is the first joint behind the skull. Trophy animals which are bing caped for the taxidermist are usually cut at this same location, so the procedure can be effectively applied to these animals also. See Photo #1 for approximate location of atlanto-occipital joint. Try to severe the brain stem as far posterior as possible during the removal process.


Step 2 - Once the head has been removed and the head is held in the upright position, the foramen (opening) around the brain stem should allow you to visualize the brain stem and the cerebellum. Trim the fibrous sheath around the brain stem and cut the cranial nerve trunks free from the brain stem. See Photo #2 for orientation of parts.


Step 3 - Insert the modified spatula (bend pointed down) between the brain stem and the cerebellum, to a sufficient depth to insure the obex area (bifurcation or Y) of the brain stem is preserved with the portion or brain stem that is removed. Remove the brain stem by cutting downward.
Step 4 - The cerebellum is suspended from the top of the brain cavity. Turn the bend of the spatula up and carefully remove a large portion of the cerebellum much the same as the brain stem was removed.


Step 5 - Photo #4 shows what the brain stem and the cerebellum look like after they have been removed from the brain cavity.


Step 6 - Section the brain stem by making a lateral cut 3/4 inch forward and behind the obex. See Photo #5 for location of the cuts. Place the center portion containing the obex in a container of 10% formalin. Place the other portions in a whirl-pac (Zip Lock) bag.
Step 7 - Section the cerebellum by removing a piece 1 inch square and placing it in the container of 10% formalin. Place the remainder of the cerebellum in the whirl-pac with the brain stem parts and freeze.