Cat Brain Removal

	REMOVAL AND STUDY OF THE CAT BRAIN David B. Fankhauser, Ph.D. Professor of Biology and Chemistry U.C. Clermont College Batavia OH 45103
Slide brain out of calvarium	This page has been accessed times since 22 Jan 2003. 21 January 1993, 30 Jan 1996, 31 Dec '96, 15 Jan 98, 18 Jan 03	Rear view of cat brain

Tools: hacksaw blade, wide bladed screw driver, flat jawed pliers

1. Clean the surface of the skull of a skinned cat of all muscle.

Pay special attention to the temporalis and muscles at the rear of the skull. Clean the occipital bone well below the occipital protuberance.

2. Make the following seven shallow cuts with a sharp hack saw blade, taking care not to saw too deeply or you will damage the brain:
a: first cut across the rear of the occipital bone, well below the occipital protuberance as low on the skull as muscle allows.

b: extend the first cut on on either side of the anterior portions of the occipital bone (cutting the R and L side).

c: Extend the previous cuts (keep them shallow) laterally through the temporal bones. Make the cuts as low on the side of the head as possible.

d: Make the last two cuts, one each above the R and L superciliary ridges, so that the cuts form an X between the eyes. These cuts should meet the cuts through the temporal bone. There are two layers of frontal bone which must be cut in the front due to frontal sinuses, therefore the cuts between the eyes must be much deeper than the other cuts.

3. Gently pry at the cuts using a wide-bladed screw driver, exploring where the cuts need to be made deeper. Start at the rear occipital cut and work forward. The frontal bone is difficult because of the large frontal sinuses. You must cut through both the exterior and interior layers of bone to free up the fron of the unit. Do not push the screw driver too deep or you will damage the underlying brain. Repeat the cutting and testing with the screw driver until the calvarium becomes loose. Do not remove yet.

4. Remove the brain-calvarium unit: Lift the front of the calvarium, reach in and cut close to the bone cranial nerves and latex/vessels so that the unit lifts from the front. Lift as much as you can and cut the spinal cord as deeply as you can to leave it attached to the brain. Lift off the brain/calvarium as a unit.

5. Explore the edges of the cut bone around the brain. Often pieces of the frontal bone forming the orbital surfaces need to be flaked off, and overhanging pieces of bone around the cerebellum and the sides of the cerebrum prevent removal of the brain. Use flat nosed pliers to break away these pieces. You may need to saw off the anterior tip of the calvarium to remove the remaining frontal sinus pieces.
It is easier to remove the brain from the calvarium if the dura mater is snipped along the ventral surface. Press and pry the cerebrum out of the calvarium, leaving the dura mater attached to the calvarium. Because the tentorium cerebelli is ossified in the cat, you must pull the brain forward to avoid breaking brain apart at the midbrain.

6. Take great care in lifting out the brain, so that as many features remain attached to the brain as possible, including the cranial nerves, and as much of the spinal cord as possible. The pituitary is usuallyretained in the sella turcica by a constriction of dura mater and becomes detached from the brain.

7. ILLUSTRATE THREE VIEWS OF THE ISOLATED BRAIN, label listed features:
a) ventral: cerebral hemispheres , the infundibulum, mammillary bodies, cerebral peduncles, pons, medulla oblongata

Here is a labeled version of the ventral brain.
Here is a version of the ventral brain with cranial nerves labeled

b) posterior: R&L cerebral hemispheres, longitudinal fissure, R&L cerebellar hemispheres, vermis, dorsal medulla oblongata

Here is a labeled version of the posterior brain.

c) posterior deep view by spreading R&L hemispheres: superior and inferior colliculi (= corpora quadrigemina), pineal gland, corpus callosum.

Here is a labeled version of the posterior deep brain.

NOTE: We will study the brain's cranial nerves I, II, III, IV, V, VII and VIII next week.

Alternative means of removing calvarium (no longer used in 2001)

Remove the calvarium by sliding it backwards, leaving the brain in the skull. In the cat, the tentorium cerebelli is ossified, and is thus a challenge to remove the calvarium without damaging the connection between the cerebrum and the cerebellum. One strategy is to cut through the calvarium and attempt to slide the calvarium to the rear , between the cerebrum and cerebellum. Alternatively, two saw cuts may be made, one above and one below the tentorium, so that the calvarium is removed in two pieces.

	1. Clean the surface of the skull of a skinned cat of all muscle. Pay special attention to the temporalis and muscles at the rear of the skull. Clean the occipital bone well below the occipital protuberance.
	2. Make the following seven shallow cuts with a sharp hack saw blade, taking care not to saw too deeply or you will damage the brain: a: first cut across the rear of the occipital bone, well below the occipital protuberance as low on the skull as muscle allows.
	b: extend the first cut on on either side of the anterior portions of the occipital bone (cutting the R and L side).
	c: Extend the previous cuts (keep them shallow) laterally through the temporal bones. Make the cuts as low on the side of the head as possible.
	d: Make the last two cuts, one each above the R and L superciliary ridges, so that the cuts form an X between the eyes. These cuts should meet the cuts through the temporal bone. There are two layers of frontal bone which must be cut in the front due to frontal sinuses, therefore the cuts between the eyes must be much deeper than the other cuts.
	3. Gently pry at the cuts using a wide-bladed screw driver, exploring where the cuts need to be made deeper. Start at the rear occipital cut and work forward. The frontal bone is difficult because of the large frontal sinuses. You must cut through both the exterior and interior layers of bone to free up the fron of the unit. Do not push the screw driver too deep or you will damage the underlying brain. Repeat the cutting and testing with the screw driver until the calvarium becomes loose. Do not remove yet.
	4. Remove the brain-calvarium unit: Lift the front of the calvarium, reach in and cut close to the bone cranial nerves and latex/vessels so that the unit lifts from the front. Lift as much as you can and cut the spinal cord as deeply as you can to leave it attached to the brain. Lift off the brain/calvarium as a unit.
	5. Explore the edges of the cut bone around the brain. Often pieces of the frontal bone forming the orbital surfaces need to be flaked off, and overhanging pieces of bone around the cerebellum and the sides of the cerebrum prevent removal of the brain. Use flat nosed pliers to break away these pieces. You may need to saw off the anterior tip of the calvarium to remove the remaining frontal sinus pieces. It is easier to remove the brain from the calvarium if the dura mater is snipped along the ventral surface. Press and pry the cerebrum out of the calvarium, leaving the dura mater attached to the calvarium. Because the tentorium cerebelli is ossified in the cat, you must pull the brain forward to avoid breaking brain apart at the midbrain.
	6. Take great care in lifting out the brain, so that as many features remain attached to the brain as possible, including the cranial nerves, and as much of the spinal cord as possible. The pituitary is usuallyretained in the sella turcica by a constriction of dura mater and becomes detached from the brain.
	7. ILLUSTRATE THREE VIEWS OF THE ISOLATED BRAIN, label listed features: a) ventral: cerebral hemispheres , the infundibulum, mammillary bodies, cerebral peduncles, pons, medulla oblongata Here is a labeled version of the ventral brain. Here is a version of the ventral brain with cranial nerves labeled
	b) posterior: R&L cerebral hemispheres, longitudinal fissure, R&L cerebellar hemispheres, vermis, dorsal medulla oblongata Here is a labeled version of the posterior brain.
	c) posterior deep view by spreading R&L hemispheres: superior and inferior colliculi (= corpora quadrigemina), pineal gland, corpus callosum. Here is a labeled version of the posterior deep brain.

REMOVAL AND STUDY OF THE CAT BRAIN