Fume Hood

Most importantly, safety is a concern in any necropsy situation. By using a fume hood, you are protecting yourself from any inhalants from the animal or preservatives. Keep the work area clean by washing it down with ethanol or disinfectant. The object in the game is to prevent becoming a study specimen yourself. So, the safer the better. Just use your head and you should be fine.

Dissecting Board

Naturally, a surface is needed to perform the necropsy. A dissecting board with a corked surface works best, but carboard boxes, multiple layers of paper towels, and discarded calendars have been used in the past. It is always nice to wrap your board in paper towel and then lay a few free pieces on the surface. When you are finished with your necropsy, wrap up the carcass in the paper towels. Any liquid of unmentionable origin will not stain or ruin the surface of the board with the wrapping in place.

Scissors and Forceps

Scissors, definitely a must have for any necropsy technician. It is a good idea to have a few pairs on hand of various sizes and sharpness. For the more delicate dissections, a fine tipped pair allows for precise and controlled cuts. With the big incisions, a rounded tipped pair protects the surrounding tissue from any unwanted nicks. For cutting bone, a old pair of scissors should be placed aside or use special bone tools. Usually a pair of retired tissue cutting scissors works best when maintaining the sharpness of the blades is no longer a concern. Forceps are also a staple item when performing a necrospy. They are very similar to duct tape, the uses for them are endless. Gripping, holding , pinching, prodding, snipping, retrieving, and tapping out Yankee Doodle on the necropsy board...there is nothing they can't do. With forceps and scissors, your necropsy will be a breeze.

Saline

Saline is very important. As you can imagine, nothing is removed from the animal without a great deal of debris, blood, and fluid coating the surface. You obviously need to rinse the tissue in order to study the structure itself. Never rinse tissue in your fixative or water. The difference in osmolarity between the tissue and the water causes cellular swelling and rupture, which is VERY BAD. Rinsing in fixative starts the fixation process causing discoloration and fusion of the debris to the surface of the tissue. Physiologic saline solution or phosphate-buffered saline maintains the tissues appearance and doesn't harm the cellular structure. If you don't have commerical saline on hand, don't worry. By mixing 4.25 grams of sodium chloride with 500 ml of distilled water, you can rest assured that your tissues are safe.

Preservatives

Obviously, in order to prepare slides from the tissues being taken, they are going to have to be preserved. For general preservation and histology techniques, 10% neutral buffered formalin meets the requirements of the job. For more specific and sophisicated techniques, numerous fixatives are available on the market to fulfill those special needs. When deciding how much fixative is needed, a good rule of thumb is to use 10 parts of fixative with every 1 part of tissue. Also, if the tissue is not processed by histology immediately, periodic changing of the preservative should assure the tissues will not dry out. Preservative will fully penetrate tissues 1 cm thick or less.With a mouse, tissues are small enough to be fully penetrated by the preservative, with the exception of the liver which can be sectioned or separated. On larger species, scoring the surface of the tissue or sectioning before fixation leads to good results.

With any necropsy, it is important to make quantitative as well as qualitative observations. It is important to take a body weight of the animal before necropsy and certain selected organs specified by your protocol. Of course, the object of this game is to only weigh the item of choice. This means judicious trimming of the attached tissue and debris to get the clearest picture. Some structures in a mouse will only weigh a few thousandth's of a gram, so an electronic scale is needed.

Pins

To pin or not to pin, that is a question as old as the cliche. The answer is left strictly up to the necropsy technician depending on his/her personal preference. But since this is an unbiased site, we will site the pros and cons for both techniques. In pinning the animal, the necropsy technician creates a stable work foundation. The animal is not moving anywhere if all four paws are pinned to the board. A 7.5 earthquake can occur, and your animal will remain in the same position. According to the majority of necropsy techniques, special commerical necropsy pins are required. But, tacks work just as well and are significantly cheaper. On the other hand, the necropsy technician may wish to have the freedom of movement if the animal is liberated from the board. Many more manipulations are allowed through this method than the pinning approach. You make the choice, it is entirely up to you.

Ethanol

As with anything worthwhile in life, there is always going to be a mess to clean up. A squirt or squeeze bottle of 70% ethanol is our cleaning agent of choice because it is so versatile. Not only does it aid in the necropsy by sterilizing the incision site and keeps fur out of tissues, it can be used during the clean up. You can clean your instruments, work area, hands, etc. If we could only buy a household cleaner that accomplishes the same tasks, the world would be a better place.