Mouse Necropsy

8/10/2019 Mouse Necropsy

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European Late Effects Project Group

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Pathbaseby thePathbase Consortium

Necropsy of the

Mouseby Vincenzo Covelli

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14th International

Symposium on

icro!osimetry "IC#$S%&&'(

Latent times to

!eterministic late e))ectsa)ter ra!iation e*posure

Centre )or #a!iation

#esearch in $ncolo+y ,$nco#ay- .res!en

Invitation to the /th

International Con)erenceon 0ealth E))ects o)Incorporate!#a!ionucli!es , Emphasison #a!ium- Thorium-Uranium an! their.au+hter Pro!ucts "0EI#%&&4(

ore nes )rom

http233eura!nesor+
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Chapter 1

Introduction

1. General

In or!er to avoi! the pro+ression o) post,mortem !e+eneration processes- the necropsy must be carrie! out as soon possible

5utolysis be+ins as soon as ca!averic ri+i!ity is over- is particularly rapi!- especially in the mouse- an! lea!s- in a short time-

to the complete lysis o) several or+ans o) the animal- startin+ )rom the inner ones

These !e+enerative an! putre)active phenomena mani)est ith variable spee!s an! intensities2 the a!renals- the coverin+

epithelia o) the +ut an! the bone marro are the )irst to be altere!6 then the liver- spleen an! 7i!neys- hile the heart an!the s7eletal muscles- the )ibrous tissues- the s7in an! bones appear more resistant


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Figure1. Position of the mouse for Autopsy

0oever- the variations o) the environmental temperature can mo!i)y the time o) appearance an! the pro+ressin+ o) these

phenomena The putre)active processes- in )act- are accelerate! by )e hours in a arm atmosphere- hile a col!atmosphere can !elay their initiation consi!erably It is there)ore necessary to store ca!avers in a re)ri+erator "8 %9C to

849C( as soon as possible a)ter !eath- in case the autopsy cannot be carrie! out imme!iately

2. Materials

5ppropriate e:uipment is necessary in or!er to carry out a care)ul necroscopic e*amination

The mouse ill have to be care)ully lai! !on on an appropriate oo!en sur)ace- or on a smooth an! s:uare table o)para))in- a )e centimetres thic7- e*ten!e! on the bac7- ith the limbs sprea! an! hel! )irmly ith pins )i*e! in the )our


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pas";i+ 1( The necessary instruments are scissors- pliers- scalpels o) varie! )ormat an! size- an! small containers )ille!ith )i*ative to collect tissue sampless to be processe! by histolo+ical techni:ues

3. Description of the autopsy cards

.urin+ the autopsy- the investi+ator must transcribe- pre)erably on appropriate car!s- all the observations ma!e !urin+ thepost,mortem e*amination These ill serve to obtain a +eneral- in!ispensable ob


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;i+ = ouse car! reportin+ histolo+ical !ia+noses "Clic7here )or a printable #T; !ocument(

In particular- a series o) characteristics shoul! be !escribe! li7e the position- the shape- the colour an! the consistency o) the

or+ans- the aspect o) the cut sur)aces- the normal or patholo+ical content o) some hollo or+ans- li7e the bla!!er- pleura orintestine- about hich it ill be spo7en belo

The better metho! o) )illin+ in the car!s consists o) !ictatin+ a complete !escription o) the or+ans an! the lesions observe! toa person ho assists

The other )ace o) the car! shoul! contain the histolo+ical !escription o) the specimen o) every or+an ta7en

4. Criteria for specimen collection and tissue fixation for histological examination

In +eneral- a histolo+ical e*amination o) some or all or+ans is necessary )or a )inal !ia+nosis6 in this respect- it is importantto 7no ho to !eal ith tissues ta7en !urin+ the autopsy

;irst o) all- it is not a!visable to leave the or+an specimens )or even a short time in air6 they shoul! be )i*e! as soon as

possible The )i*ative can be 1&> bu))ere! )ormalin- '> ?en7er )ormolic aci!- or @ouin As )i*ative The stora+e o) the sectionsin the )i*ative shoul! not e*cee! %4 or 4B hours

It is rarely a!visable to )i* lar+e entire or+ans- as they have been remove!- but it is su++este! to ta7e only some sections-pre)erably those shoin+ patholo+ical characteristics The instruments )or this operation are a thin scalpel or a common razorbla!e oreover- it is convenient to !eal each or+an in a !i))erent ay be)ore the )i*ation The heart ill be !ivi!e! in tohalves ith a me!ian cut ta7en )rom the ape* to the base- so that the )i*ative can be absorbe! more :uic7ly 5 me!ian cut

alon+ the +reater a*is ill be e*ecute! )or 7i!neys an!- in some cases- also )or the testes These metho!s are essential inor!er to obtain +oo! histolo+ical sli!es
http://www.eulep.org/Necropsy_of_the_Mouse/histopathology_card.rtfhttp://www.eulep.org/Necropsy_of_the_Mouse/histopathology_card.rtfhttp://www.eulep.org/Necropsy_of_the_Mouse/histopathology_card.rtf


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Chapter 2

External examination

The e*ternal e*amination is the )irst proce!ure to carry out on the animalAs bo!y

1. General condition

The investi+ator ill e*amine the animalAs +eneral con!ition2 state o) nutrition an! !evelopment o) the s7eletal muscular

masses- presence o) s7in alterations- )ur- any super)icial lesions

5n animal )oun! in a ba! nutritional con!ition su++ests that a chronic !isease mi+ht be the cause o) !eath I) the bo!y is in a

+oo! +eneral state this is an in!ication o) a su!!en !eath- probably cause! by an acute process

2. !in and cutaneous adnexa

;rom the e*amination o) the s7in- the presence o) traumatic oun!s ill be obvious- as ell as that o) ulcers- acute or

chronic in)ectious processes- some types o) tumours o) the s7in- or o) the mammary +lan!s

$e!ematous phenomena can moreover be appreciate! as they usually cause the s7in to become sollen- smooth an! +lossy

Such phenomenon is calle! oe!ema hen it is limite! to some bo!y areas- an! anasarca hen- instea!- is +eneralize! to the

hole bo!y Phenomena o) this type can be correlate! ith many causes- li7e post,in)ectious to*aemia or +eneralize!leu7aemic processes

5nother character to ta7e into consi!eration !urin+ the e*ternal e*amination is the state o) the )ur The )ur appears rou+h-

!ry an! hirsute in a mouse in ba! shape- hen a serious !isease becomes chronic- or !ue to the presence o) parasites Inthese cases- )ur has a po!ery aspect Crusty an! !ry areas can also be present- )re:uently o) +rey,yelloy colour In somestrains- li7e the C'@l- a similar aspect is )re:uently associate! ith the presence o) parasites or )un+i oreover- in thisstrain the !epilate! areas sho particular characters- such as small spec7s- pre)erentially localize! on the hea! or on the

bac7 The phenomenon o) !epilation can also be present in animals a+e! or treate! ith hi+h !oses o) ionisin+ ra!iation Inthis last case- such phenomenon appears more prematurely

In pi+mente! strains- variations o) )ur colour are also )oun! a)ter ra!iation e*posure In particular- it is observe! that colourremains unchan+e! until the secon! month a)ter the treatment- also a)ter hi+h !oses- an! then it be+ins to turn hite inseveral bo!y re+ions The hea! is the )irst to become +rey- then the !epi+mentation e*ten!s in the or!er to nec7- to thebac7- an! )inally the entire )ur turns to hite The !epi+mentation phenomenon is absent in unirra!iate! an! a+e! mice The

!epi+mentation- in )act- is a phenomenon typical o) the treatment ith ionisin+ ra!iation

3. "atural orifices

It is a!visable to report the anomalies an! the lesions o) the natural ori)ices- as the mouth- the nose an! the anus to

complete the e*ternal e*amination

The lesions o) the mouth are easily !etectable by ma7in+ a care)ul e*amination o) the state o) the ton+ue- o) the mucosa o)

the )auces- o) the lips- an! o) the teeth

5nomalies o) the ton+ue are rare an! substantially consist o) an increase or in a !ecrease in volume- usually associate! ithcon+enital alterations2

Interestin+ mo!i)ications can be observe! sometimes on the labial an! oral mucosa Dormally- the colour o) this mucosa is

rose- but one possible )in!in+ is a pale mucosa in case o) erythroi! anaemia or a bluish in passive hyperaemia oreover- inmice !ea! )rom in)ectious !iseases- haemorrha+es o) the submucosa can be )oun! as petechia6 in some cases super)icia

erosions o) the mucosa- ulcers- or vesicles- are also present

Lesions o) teeth are observable in almost all animals a+e! or treate! ith hi+h !oses o) ra!iation- an! consist o) several!e+rees o) loss- erosion or )racture- ith particular re+ar! to the incisors- hich prevent the animal )ee!in+ a!e:uately It isthere)ore necessary- hen a un!ernourishe! mouse is )oun!- to care)ully e*amine the state o) its teeth- hose !e)ects- i)

very serious- can be a cause o) !eath

The aspect o) the mucosa o) the nasal openin+s ill have to be also reporte!- as ell as the eventual presence o) e*u!ates or

o) haemorrha+es This last report- calle! epista*is- may not only be connecte! to the action o) a trauma- but also toulcerative phenomena or rupture o) the all o) a vessel


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oreover- e:ual attention shoul! be pai! to the e*amination o) the anal openin+ In the animal a))ecte! by !iarrhoea- theanus is nearly alays smeare! by )aeces an!- in some cases- also by bloo! 5 prolapse! intestine "rectal prolapse( can also

be observe! in the anal area This lesion- noticeable also !urin+ the li)e o) the animal- shos an intense !ar7,re! colour ith)re:uent ulcerative processes !ue to haemorrha+ic stu))in+ o) the alls o) prolapse! intestine- an! to bacterial invasion Suchlesions are rather )re:uent an! are )oun! in nearly all strains o) mice


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Chapter 3

Internal examination

;olloin+ the e*ternal e*amination- the investi+ator can procee! to the !issection o) the animal

In some cases the interest o) the researcher is )ocusse! on a speci)ic area or or+an6 in this case

the investi+ator oul! be tempte! to limit his macroscopic e*amination to that particular re+ion-

ithout tryin+ to have a +eneral picture o) all the or+ans o) the animal This type o) limite!

survey is una!visable It is alays better to carry out a complete necropsy o) the mouse possiblyith a )ast an! accurate metho!- hich reveals the particular characteristics o) all the or+ans

an! their evi!ent lesions

We ill there)ore !escribe a systematic metho!- !esi+ne! to provi!e an! accurate autopsy o) alaboratory mouse


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;i+ 4 $penin+ o) the mouse s7in2 e*ternal e*amination o) subcutaneous tissues- muscles- lymphno!es an! mammary +lan!s "Clic7 on the ima+e )or a lar+er version(

$nce the animal is )i*e! on the appropriate table in the position !escribe! previously- the

investi+ator ill ma7e a small cut at the level o) the pubis- such as to allo the entrance o) one

point o) the scissors Then- the investi+ator ill per)orm a me!ian lon+itu!inal cut superiorly to

the chin- havin+ care to accurately seperate the s7in )rom the un!erlyin+ musculature


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The s7in is then !issecte! an! turne! on one si!e an! then on the other- so as to obtain ane*amination )iel! as i!e as possible ";i+ 4( The characteristics o) the subcutaneous

super)icial lymph no!es- mammary +lan!s an! o) the s7eletal muscles ill then be apparent

1. u#cutaneous

The presence o) a +lossy- +elatinous an! clear li:ui! )ille! subcutaneous space con)irms the

!ia+nosis o) oe!ema- also noticeable !urin+ the e*ternal e*amination- hile a more or less

e*ten!e! collection o) bloo!- ith enlar+e! mar+ins- in!icates the presence o) haematoma

Small- more or less numerous- haemorrha+ic petechia can moreover be observe! more)re:uently in mice a))ecte! by an in)ectious !isease Variations o) the normal colour can also be

)oun! )or the presence o) particular pi+ments- as it happens in icterus

2. uperficial and deep lymph nodes

Anatomical outline.In normal con!itions- the lymph no!es o) the mouse are easily !etectable

They are numerous- o) variable size in !i))erent strains o) animals- +reyish- an! shape! as a

small pea or bean 5ccor!in+ to the localization- they can be classi)ie! as super)icial lymph

no!es- situate! in the subcutaneous area an! near the s7eletal muscular masses- an! as !eeplymph no!es- situate! insi!e the thoracic an! ab!ominal cavity or close to the or+ans ;i+ure '

shos a +eneral picture o) the morpholo+ical characteristics o) every lymph no!e an! its

localization in the normal mouse
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Examination.$) the several lymph no!es- e ill !escribe the particular characteristics as theshape- the volume- the consistency an! the eventual relationships beteen them an! the

un!erlyin+ plans

The lymph no!es near the centre o) an in)lammatory process )re:uently sho increase o) volume

an! sometimes haemorrha+ic characteristics

;i+ $bservation o) the mesenteric lymph no!e


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When- on the contrary- the hole lymphatic system o) the animal is a))ecte!- this can beascribe! to a lymphoma @ut also in these cases- the only character that can be observe!

macroscopically is enlar+ement hich )re:uently is also o) remar7able !e+ree There)ore- it ill

be more pru!ent to ma7e a !ia+nosis o) lymphoma- even i) at this sta+e enou+h in!icative- only

hen the necropsy is )inishe!6 alterations o) the !eep lymph no!es an! o) other or+ans- li7e thethymus- spleen an! the liver- can be o) help

The investi+ator must also e*amine- ith particular attention- the state o) the mesenteric lymph

no!e This lymph no!e in the mouse is )oun! intimately connecte!- by means o) mesentery- to

the ascen!in+ colon ";i+ (- an! is easily !etectable hen the small intestine is re)lecte! on thele)t si!e In some !iseases- the mesenteric lymph no!e can sho remar7able variations in

colour- consistency- an! volume until becomin+ various times lar+er than the normal This

happens both in the lymphomas that in the mouse it is believe! to ori+inate


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The most )re:uent lesions o) the mammary +lan!s are the tumours The beni+n or mali+nanttumours that ori+inate )rom the !uct epithelia are a!enomas an! a!enocarcinoma These

tumours appear macroscopically as plates or no!ules o) various consistency- haemorrha+ic-

sometimes o) a cystic aspect- o) !iameter variable )rom a )e millimetres to some centimetres

Less )re:uent are tumours that have a connective tissue ori+in- li7e )ibroma or )ibrosarcoma-hich sho a oo!en consistency- are mar7e!ly invasive- an! o)ten ulcerate! at the s7in

sur)ace

In some strains o) mice- in particular in many C=0 lines- a spontaneous inci!ence as hi+h as 1&&

percenta+e o) these neoplasms is observe! In other strains- the increase o) inci!ence o) theseneoplasms can be the conse:uence o) chemical carcino+en- ra!iation or hormone treatment

4. !eleton and s!eletal musculature

The various sections o) the s7eleton may be e*amine! in a systematic ay only hen there are

speci)ic clinical,scienti)ic interests $therise- the inspection ill be limite! to those s7eletasections that appear as the autopsy procee!s 5 complete e*amination o) the s7eleton ill be

possible only by means o) one +oo! ,ray ";i+ B(
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;i+ B ouse ,ray picture

With this techni:ue- it ill be possible to !etect- in a more !etaile! ay- both the neo)ormations

o) the bone "tumours(- in many cases macroscopically evi!ent by their mass an! )or invasion o)the a!


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animals The state o) the s7eletal muscles must be then ta7en into consi!eration 5 mar7e!atrophy is a conse:uence o) an in)ectious !isease- o)ten cause! by viruses "!ermatomyositis(

$nce the observation o) the super)icial or+ans is over- the investi+ator ill procee! ith the

e*amination o) the inner cavities o) the animal- startin+ )rom the ab!omen- then the thora*-

an!- )inally- the s7ull


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Chapter 4

$#dominal ca%ity

1. &pening and general examination

$nce the ab!ominal cavity is opene!- usin+ a cut alon+ the me!ian a*is o) the muscular all ";i+/(- the investi+ator shoul!note phenomena hich ill be !isturbe! later in the pro+ress o) the autopsy There)ore the position o) the or+ans- the

presence o) any a!hesions or li:ui!s in the cavity- ill have to be observe!


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;i+ / $penin+ o) the ab!ominal all "Clic7 on the ima+e )or a lar+er version(

Variations o) or+an position "ptosis or situs inversus(- or absence o) an or+an- are con+enital anomalies an! very rare

occurrence 5!hesions beteen several or+ans- !ue to in)lammatory or neoplastic processes- as ell as amounts o) li:ui!s-more or less abun!ant- are more )re:uently seen

The abun!ant presence o) li:ui!s in the ab!ominal cavity is an in!ication o) a patholo+ical con!ition- an!- in this case- it isimportant to care)ully recor! this phenomenon- in or!er to achieve an accurate !ia+nosis

5n abun!ant- clear- lemon,coloure! li:ui! "ascites( is as a result o) portal hypertension- or o) some severe lesions2 renalnephritis or nephrosclerosis- hepatic cirrhosis or car!iac lesion These )in!in+s are also )re:uent in mice bearin+ +eneralize!

lymphoma or leu7aemia- associate! ith the presence o) abun!ant in)iltration o) neoplastic cells

The presence o) less or more abun!ant bloo! "hemoperitoneum( coul! be a conse:uence o) ab!ominal bloo! vessel ruptures-or o) in)lammatory processes o) the arteries "an+itis- polyarteritis(- trauma- or o) spontaneous ruptures o) aneurisms Insome cases- the hemoperitoneum can also be a conse:uence o) a rupture o) a vessel in a !etermine! or+an- a))ecte! by

hepatic tumours or lymphoma3leu7aemia

The presence o) bloo! in the ab!ominal cavity )re:uently pro!uces an in)lammatory reaction o) the peritoneum- calle!

peritonitis Various types o) peritonitis can be observe!2 the serum,)ibrinous peritonitis or the purulent one- easily!istin+uishable on the basis o) e*u!ate peculiarities The e*u!ate ill be serous ith thin )ibrinous )ilaments in the )irst case-an! !ense- creamy an! yelloish in the secon! case

In the ab!ominal cavity- mainly in the pelvic re+ion- small masses o) a!ipose necrotic tissue can also be )oun!- attache! by a

connective pe!uncle to the ab!ominal all This a!ipose !ar7,coloure! tissue can easily be con)use! ith small +lan!s orother structures

$nce the observation o) the ab!ominal cavity is complete!- the investi+ator can procee! to the e*traction o) the in!ivi!ualab!ominal viscera an! to their !etaile! e*amination

2. pleen

Anatomical outline.The spleen is an or+an o) pre!ominantly lympho,erythropoietic )unction The parenchyma o) this or+ancontains2 a( a tissue ith erythropoietic )unction calle! re! pulp- constitute! by vessels an! cor!s o) various types o) re! cells"haemocytoblasts- erythrocytes- leu7ocytes- me+a7aryocytes(6 b( a lymphoi! tissue calle! hite pulp

The spleen is situate! in the le)t superior ab!ominal :ua!rant6 it has a len+thene!- oval- sli+htly curve! shape

The ventral )ace is smooth an! conve*6 the !orsal one is sli+htly concave- oriente! toar!s the stomach- to hich it isconnecte! by means o) the +astrosplenic li+ament oreover- the hilum- throu+h hich the splenic vessels enter the or+an-

lies on the !orsal )ace o) the spleen

In a youn+,a!ult mouse the spleen measures appro*imately 1' millimetres in len+th- = millimetres in i!th- % millimetres in

thic7ness Its avera+e ei+ht is appro*imately o) 1&& m+ Un!er normal con!itions- the spleen has a )riable an! so)tconsistency- a smooth sur)ace covere! by a thin an! transparent capsule- an! a !ar7,re! colour Small variations in shape

an! volume- or the presence o) rare aberrant accessories no!ules o) splenic tissue- can be rarely observe! in animals o)!i))erent strains an! a+es In the spleen o) the C'@l mice it has been notice!- ith a certain )re:uency- the presence o)

blac7 spots- mainly localize! on the postero,lateral an! anterior part o) the or+an6 these areas are )oun! in the re! pulp an!

are !ue to the presence o) melanin in the cells

emo!al and examination The spleen ill be the )irst visceral or+an o) the ab!ominal cavity to be e*tracte! usin+teezers to hol! an! then cut the hilum to+ether ith the +astrosplenic li+ament ";i+ 1&(

The splenectomy is a simple operation since the or+an is easily !etache! ithout abun!ant haemorrha+e

.urin+ this e*traction the pancreas can also be easily remove! !ue to its intimate connection ith the spleen

The anatomo,patholo+ical e*amination o) the spleen must ta7e into consi!eration volume- consistency- colour- mar+ins an!any evi!ent lesion


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;i+ 1& Spleen e*traction

There are lesions- li7e the lymphoma3leu7aemia- in hich the or+an is enormously enlar+e! "splenome+aly( ith a tense

capsule- o) a har! consistency- an! o) rose or +reenish colour "chloroleu7emia( In these cases- i) a lon+itu!inal cut o) theor+an is e*ecute!- the investi+ator ill be able to )in! on the cut sur)ace proli)eration o) re! pulp "myeloi! leu7aemia(- orpresence o) trabecular stripes- or many lar+e lymphatic )ollicles easily visible on the re! pulp "lymphoma( The presence o)lar+e haemorrha+ic zones can be associate! ith the rupture o) vessels

5n enlar+e! spleen o) so)t consistency an! ith an elastic capsule- throu+h hich a !ar7,re! colour is visible- is an in!icationo) in)ectious process at the moment o) !eath In this case- at the cut- the re! pulp ill appear hyperplastic- )loin+- an!

easily removable ith the scissors

5n enlar+ement is also seen in the so,calle! Gspleen stasisG )or the abun!ant presence o) bloo! hich pools in the or+an5mon+ the causes that can pro!uce this con!ition- it is orth rememberin+ serious !isturbances o) the circulation cause! bycar!iopathies or pulmonary lesions

oreover the spleen can be a))ecte! by in)arcts- hich sho some peculiar characteristics in relation to the perio! over hichthe lesion has been mani)este! 5 stri7in+ly trian+ular hemorrha+ic area- ith the base usually oriente! toar! the sur)ace-

su++ests a recent in)arct $n the contrary- a sclerotic cicatri* su++ests that the lesion has ta7en place ell be)ore the !eatho) the animal an!- there)ore- is not correlate! ith the cause o) !eath

;inally the presence o) a circumscribe! visible mass on the sur)ace o) the spleen- usually smooth- haemorrha+ic an! o) !ar7,

re! colour is associate! ith vessel hyperplasia or neoplasia "an+iomas(

3. 'ancreas

The +lan!ular pancreatic tissue in the mouse is completely enclose! in the mesenteric a!ipose tissue an! !oes not appear astrue compact or+an as in the human bein+ ;re:uently- in the ol! animals- the pancreas is atrophic- because it is completely

lac7in+ in acini The atrophy o) the pancreas can also be the conse:uence o) a chronic pancreatitis or no!ular polyarteritis Insome cases- the pancreatic !ucts can be )oun! enlar+e! as cysts !ue to stenosis o) the pancreatic !uct- an! its rupture maycause a !isease such as )at necrosis "steatonecrosis(

Primary tumours are e*tremely rare in the mouse Within these neoplasms- the beni+n types are represente! by no!ularhyperplasia- an! by the so,calle! a!enomatosis- very !i))icult to !istin+uish macroscopically The mali+nant tumours- veryo)ten o) epithelial ori+in "a!enocarcinoma(- are hi+hly invasive- mainly in the mesentery an! in the a!


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emo!al and examination.$nce the e*ternal observation o) the spleen an! pancreas is complete!- the investi+ator canprocee! to the e*amination o) the +ut- inclu!in+ the stomach- an! then to its e*traction To this aim- it is necessary to ta7e

into consi!eration the e*ternal aspect o) the intestine an! ho it is arran+e!- in or!er to !etect possible !istension o) theall- usually cause! by the presence o) putre)active +as- or colour variations- cause! by enteritis- colitis- or )or possiblepresence o) bloo!

5t this is point- it is su++este! that the investi+ator ill )irst procee! to e*amination o) the mesenteric lymph no!e

With


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;i+ 11 Stomach an! +ut e*traction

I) the investi+ator hol!s this se+ment o) intestine "the cut rectum( ith )orceps an! li)ts upar!s an! superiorly - the various

intestinal se+ments can be +ra!ually e*tracte! procee!in+ in a cau!al,cranial !irection- cuttin+ the insertion o) the mesentery)rom the vertebral column up to the stomach I) you ma7e another cut at the level o) the oesopha+us- close! to the car!iacsphincter- the proce!ure is complete! so that the stomach an! the intestine can be remove! in one piece an! are then rea!y)or a !etaile! e*amination @e)ore procee!in+ to the luminal e*amination- hoever- it is a!visable to carry out one technica

proce!ure consistin+ in pullin+ out the )ull intestine- to achieve this you must procee! by cuttin+ the intestine insertion o) themesentery ";i+ 1%(

$penin+ o) the stomach an! the intestine The openin+ o) intestine an! stomach can be ma!e either !urin+ the autopsy- ith

)resh or+ans- or a)ter a )e hours o) )ormalin )i*ation To pass to the internal e*amination o) the +ut lumen- the investi+atormust procee! ith a sin+le lon+itu!inal cut up the intestine at the level o) rectum- an! )rom here continuin+ to the stomach-ta7in+ care that this cut be per)orme! close to the mesentery insertion


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;i+ 1% Fut e*tracte! an! rea!y to be e*amine!

The investi+ator is no able to investi+ate the contents o) the intestine- all thic7ness- colour- aspect o) mucosa an! its

obvious lesions In the +lan!ular part o) the stomach- particularly in .@5 strain- it is possible to observe proli)erative lesionso) the mucosa- hich can also be macroscopically !ia+nose! as a tumour The mucosa o) the lar+e an! small intestineappears re!!ish- hyperplastic an! ith )ine haemorrha+ic petechia or small ulcers in case o) an in)lammatory lesion "enteritisan! colitis( ;urthermore- in haemorrha+ic +astritis there is an abun!ant presence o) bloo!- hich appears as a !ar7 )lui!

The small intestine alls are normally scattere! by small- hite- protuberant no!ules- calle! PeyerAs patches- hich- at theautopsy- can be erroneously !ia+nose! as small tumours or metastases In +eneralize! lymphoma- these patches- to+ether

ith super)icial an! !eep lymph no!es- can appear har!ene! in te*ture- an! remar7ably enlar+e! to become very bi+no!ules o) +rey colour ;inally- in the a!vance! sta+e o) this lesion- the Peyer As patches can cover the entire intestine allhich ill then appear uni)ormly thic7ene!

.i+estive system tumours are )re:uent in the mouse an! easy to !ia+nose The epithelial mali+nant tumours

"a!enocarcinoma( are usually localize! in the +lan!ular part o) the stomach an! in the small an! lar+e intestine mucosaThey appear as lar+e ulcerate! masses ith a !istinct invasive character ore rarely the investi+ator may observe lar+etumours in the )orestomach an! small tumours- or polyps- usually localize! in the !uo!enum o) the .@5 strain

(. )i%er and #iliary ducts

Anatomical outline.The liver is a lar+e +lan!ular or+an hich occupies a a lar+e portion o) the ab!ominal cavity o) themouse With its superior conve* sur)ace- the liver a!heres to the !iaphra+m- hile its in)erior concave sur)ace is in contactith the stomach an! the !uo!enum

The liver has )our lar+e lobes hich


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;i+ 1= Liver e*traction

The normal colour o) the liver is !ar7,re!!ish The liver is har!- but )riable hen one e*erts pressure on the parenchyma Theei+ht o) the liver is o) appro*imately 1=4 + in a mouse o) three months o) a+e

The cholecyst- also calle! +all bla!!er- is visible on the in)erior sur)ace o) the or+an here it appears li7e a small a ba+ o) a)e millimetres in !iameter The bile- pro!uce! by the liver- reaches the +all bla!!er via the hepatic !uct- here it isconcentrate!6 the bile reaches the intestine throu+h the cystic an! the common bile !ucts

emo!al and examination In or!er to remove the liver- the investi+ator cuts- ith scissors- the )alci)orm an! coronaryli+aments that 7eep the or+an intimately connecte! ith the !iaphra+m- ta7in+ care not to cause lesions ";i+ 1=( $nce theliver is isolate!- it ill be remove!- to+ether ith the in)erior vena cava an! the hepatic vessels The investi+ator ill then


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pass to the e*ternal e*amination o) the or+an- ta7in+ care to !escribe the 7ey characteristics such as volume- consistency-colour- an! +eneral aspects o) the cut sur)ace

In some lesions- variation o) the volume o) the or+an is o)ten associate! ith mo!i)ication o) the liver mar+ins2 in the case o)or+an atrophy- such as acute atrophy o) the liver an! cirrhosis- the mar+ins are thin an! sharp6 hile they become lar+e an!roun! in all the lesions associate! ith hepatome+aly- such as hepatostasis- )atty !e+eneration- an! in)lammation

$) course- an increase in liver volume is also observe! in neoplasia- an! it must be remembere! that hepatomas are amon+the most )re:uent tumours observe! in the mouse- particularly in the C=0 strain These tumours consist o) +lobular masseso) variable size- )rom a )e millimetres to some centimetres- an! are usually localize! in one o) the +reater lobes o) the liver6

they are usually ell circumscribe! an! o) so)t consistency6 their colour is similar to that o) normal liver tissue

5 liver enlar+ement can also be observe! in the case o) +eneralize! leu7aemia3lymphoma accompanie! ith an increase in)irmness- an! variation o) the colour )rom rose to !ar7,+reenish In some cases- the presence o) irre+ular no!ules on theor+an sur)ace is observe!

I) the investi+ator procee!s to ma7e a lon+itu!inal cut alon+ the +reater lobes- he3she ill then be able to observe morecare)ully the structure an! the consistency o) the or+an Possible variations o) the colour an! aspect o) the lobe can be seen

In many types o) lymphoma- the patholo+ist mi+ht observe a massive in)iltration o) neoplastic cells associate! ith apronounce! proli)eration o) the connective tissue- ith the appearance o) small islan!s or lar+e stripes- hich usually alterthe normal architecture o) the lobes

In )atty !e+eneration- some yelloish areas- surroun!e! by !ar7,re! parenchyma- are observe! at the cut sur)ace $n the

contrary- in the con!ition o) GstasisG- the normal lobular structure seems preserve!- even i) a mar7e! con+estion is present-!ue to an abun!ant bloo! content in the lobes

$nce the liver observation is complete!- the or+an is turne! ith its in)erior )ace toar!s the investi+ator to e*amine the +allbla!!er The e*ternal characteristics o) this or+an shoul! be recor!e!- such as shape- size- an!- soon a)ter havin+ pro!uce!one small cut- the content o) the or+an an! the state o) the coverin+ mucosa

The volume o) the +all bla!!er is increase! by bile retention- mainly cause! by the presence o) stones or as a conse:uence o)

the pressure o) ab!ominal tumour masses $ther con!itions may cause a volume !ecrease6 such as chronic in)lammatory!iseases- !uctal obstruction- an! tumours

The +all bla!!er li:ui! content- hen present in su))icient amount- shoul! be !ran up into a pipette an! e*amine! Usually-the li:ui! is more or less clear an! o) a bron colour Very rarely- the investi+ator ill note the presence o) stones6 these aresmall- ith smooth irre+ular sur)aces- o) !i))erent colours )rom !ar7,bron to +rey- !ue to their !i))erent contents ;inally-

the mucosa shoul! be e*amine! In normal con!itions- it has a smooth aspect an! shos an irre+ular- re!!ish sur)ace !ue toin)lammatory !iseases only in )e cases

*. +rinary apparatus

$nce the ab!ominal cavity is )ree! o) the or+ans previously remove!- the investi+ator ill be able to more easily e*amine the

urinary apparatus


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;i+ 14 Ji!ney an! ureter e*traction

Anatomical outline.The urinary apparatus consists o) 7i!neys- ureters- bla!!er an! urethra The 7i!neys are paire! or+ans

locate! on the !orsal "posterior( all o) the ab!omen- besi!e the vertebral column They have a bean shape In the concaveme!ial mar+in o) the or+an- you can appreciate the presence o) the hilum o) the 7i!ney- )rom hich the main vessels an!nerves e*it The ureter also ori+inates )rom this same area- calle! the renal pelvis

The variation in !imensions or position o) these or+ans mi+ht be easily appreciate! by comparin+ the to 7i!neys In )act-

the ri+ht is usually lar+er an! heavier that the le)t one- an! it is also positione! more cranially The ei+ht o) the ri+ht 7i!neyis appro*imately %1& milli+rams- an! that o) the le)t is %&& milli+rams The 7i!neys sho a har! compact consistency- an! a

re!!ish colour that sometimes turns to yello

The ureters are to thin small !ucts that connect the 7i!neys to the bla!!er Their main )unction is to allo the urine-pro!uce! by 7i!neys- to be collecte! in the bla!!er The ureters en! up separately in the posterior part o) the bla!!er- closeto the nec7

The bla!!er appears as a small oval ba+- covere! by a thin +reyish all- an! lies in the anterome!ial area o) the ab!ominalcavity In its in)erior part- this ba+ shrin7s an! continues in the nec7 an! then in the urethra

The urethra consists in one me!ial small !uct that +oes )rom the nec7 o) the bla!!er to the e*ternal openin+ o) the penis inthe male mouse- an! in the )ossa clitori!is in )emales This tract represents the last part o) the urinary system- throu+hhich the urine is eliminate!

Kust )or topo+raphical reasons- the a!renal +lan!s are !escribe! in this chapter- !ealin+ ith the urinary system- because

these +lan!s lie on the superior pole o) the 7i!neys an! are intimately


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With this techni:ue- the prostate +lan!- hich is very !i))icult to !etect macroscopically- ill then be remove!

.iseases that alter the shape an! the volume o) this or+an "prostatic hypertrophy- tumours( are observe! very rarely in the

mouse6 in these cases only- the investi+ator ill be able to !escribe its macroscopic characteristics

The )emale an! male +enital apparatuses ill be e*amine! separately- havin+ speci)ic con)i+urations in each se* an! !i))erent

relationships ith the surroun!in+ or+ans

,. -emale genital apparatus

Anatomical outline.The +enital apparatus o) the )emale mouse inclu!es the uterus- the ovaries- the ovi!ucts an! the

va+ina

The uterus is )orme! by a tubular me!ian part "bo!y o) the uterus( an! to lateral )ormations "lateral horns( The cau!apart o) the uterus bo!y is calle! the nec7

The uterus is )oun! in the in)erior part o) the ab!ominal cavity an! a!heres to the posterior all o) the ab!omen Inparticular- the bo!y o) the uterus is place! anteriorly to the urinary bla!!er an! is covere! by a serosa a!herent to theposterior all o) the ab!omen In normal con!itions the colour o) the or+an is +reyish

The ovaries lie close to the in)erior pole o) the 7i!neys an! are tie! to the posterior all o) the ab!omen by means o) themesovarium They are small bilateral spherical or+ans ith smooth sur)aces .urin+ the perio! o) the se*ual maturity- theovaries assume a no!ular aspect !ue to the presence o) )ollicles an! corpora lutea

@eyon! their role as en!ocrine +lan!s- the ovaries have the )un!amental )unction o) pro!uction o) the oocytes that- oncee*pelle!- pass into the uterus throu+h the ovi!ucts- an! there are )ertilize!

The ovi!ucts are to ti+ht an! small tubes- rappe! aroun! themselves as a ball6 they connect the ovaries to the horns o)

the uterus

;inally- the va+ina is a short channel that be+ins )rom the nec7 o) the uterus an! en!s e*ternally in )ront o) the anal openin+

In the ab!ominal cavity- the va+ina lies in )ront o) the rectum an! behin! the urethra

emo!al and examination.The ;emale +enital apparatus is e*cise! by ma7in+ a cut on the me!ian bo!y o) the uterusclose to the nec7 ";i+ 1'( ;rom here- procee!in+ upar!s- the mesometrium li+aments- that )i* the or+an to the posteriorall o) the ab!omen- are cut up to the level o) the ovaries at the bac7The investi+ator ill then !elicately cut those

li+aments by hich the ovaries are attache! to the in)erior poles o) the 7i!neys- as ell as )rom the mesovarium li+aments-ith hich the ovaries are


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;i+ 1' Uterus #emoval "Clic7 on the ima+e )or a lar+er version(

The investi+ator ill ma7e some cuts on the sur)ace o) the or+an to investi+ate the consistency- the thic7ness o) the allsan! the character o) the contents oreover- enlar+ements are )oun! in case o) leu7aemia3lymphoma or cystic hyperplasia o)

the en!ometrium

The ovaries are then e*amine! )or their volume an! sur)aces Tumours "luteoma- tubular,a!enoma(- cysts

leu7aemia3lymphoma are some o) the lesions that more )re:uently a))ect this or+an an! in!uce variations o) shape orvolume

. Male genital apparatus


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Anatomical outline.In the male mouse- the +enital apparatus inclu!es the testes- receptacula seminis- the epi!i!ymis- thepenis an! the preputial +lan!s

The testes are to or+ans o) oval shape ith a !iameter o) a )e millimetres- situate! at the si!e o) the bla!!er an! insi!ethe scrotum They are covere! by a smooth an! transparent membrane "tunica albu+inea( Un!er normal con!itions- theyare +reyish,hite- o) so)t elastic consistency The avera+e ei+ht is 1&= m+ )or the ri+ht an! 1&1 m+ )or the le)t testis

The testes consist o) numerous tubules covere! ith various cell layers an! their main )unction is the pro!uction o) maturese*ual cells or spermatozoa oreover the testes pro!uce male se*ual hormones or an!ro+ens

The spermatozoa pro!uce! )rom the testes pass into the urethra throu+h the e*cretory !ucts "epi!i!ymis an! the !e)erent!ucts(

The receptacula seminis are to bilateral structures that are )oun! at the bla!!er si!es an! are in communication ith the

urethra They are )orme! )rom numerous small secretion )ille! cavities They have a curve! )lattene! shape an! a clear,+reycolour $in+ to their vesicular con)ormation these )ormations have a so)t consistency

In the mouse- the preputial +lan!s are inclu!e! in the connective tissue- they are lea) shape!- an! lie above the penis Theyare o) a !ar7,+rey colour an! a so)t consistency

emo!al and examination. The investi+ator )irst o) all must chec7 the position o) the or+an- because- hen the ab!ominacavity is opene!- the testes are o)ten )oun! outsi!e the scrotum- leanin+ to the posterior all o) the ab!omen an! at the

si!es o) the bla!!er6 there)ore- by +raspin+ them !elicately- they may be remove!- cuttin+ the e*cretory !ucts close to theiroutlet in the membranous urethra ";i+ 1(


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;i+ 1 Testis e*traction

The investi+ator ill then recor! the shape- the volume- the consistency- the presence o) tumour masses an! the characterso) the epi!i!ymis I) a me!ian lon+itu!inal cut o) the testes is ma!e- he3she ill also appreciate the colour- cut sur)ace

consistency- presence o) in)lammatory zones or o) neoplasms

5 rupture o) a bloo! vessel that accompanies the e*cretory !ucts or the same testis usually causes the enlar+ement o) the

or+an In this cases the testis appears mar7e!ly enlar+e! ith i!e areas o) bloo! in)iltration- the remainin+ parenchyma isre!uce! to a small necrotic portion

The receptacula seminis are o)ten e*pan!e! an! )ille! o) serous li:ui! This happens hen an obstacle is present in thee


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in)lammation These lesions are o) +reat !ia+nostic importance in the mouse- because they can be o)ten the cause o)peritonitis

In or!er to complete the e*amination o) the male +enital apparatus- the investi+ator ill then e*amine the penis an! thepreputial +lan!s The abscesses o) these +lan!s represent a rather common lesion in ol! animals an! they can sometimes be!etectable on the correspon!ent ulcerate! s7in


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Chapter (

/horacic ca%ity

1. &pening and general examination

The investi+ator ill no procee! to open the thoracic cavity startin+ )rom the last rib by cuttin+ the costal cartila+es at theirpoint o) union ith the bone Continue cuttin+- procee!in+ up both si!es- until reachin+ the articulation o) the sternum ith

the ribs";i+ 1(6 the in)erior part o) the sternum is raise! ith the clamp an!- then- its insertions ith the )ront mar+ins o)

the !iaphra+m are cut Jeepin+ the sternal plate raise!- the insertions o) its inner )ace ith the parietal pleura an! thepericar!ium are )inally separate!


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;i+ 1 $penin+ o) the thoracic cavity "Clic7 on the ima+e )or a lar+er version(

$nce the thoracic cavity is opene!- the investi+ator ill be able to pass to the removal o) the viscera

5lso in this case- as it as in!icate! )or the ab!ominal cavity- it is necessary to pay attention to some characteristics that canbe mo!i)ie! as a conse:uence o) the e*traction techni:ues In this respect- the investi+ator must consi!er the position o) theor+ans "situs inversus- con+enital anomalies(- the presence o) a!hesions "as a result o) pleuritis or pericar!itis( or hy!ro, an!haemothora*

2. /hymus


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Anatomical outline.The thymus in the mouse consists o) to lobes- an! lies on the me!ian line o) the vertebral column-close to the base o) the heart

The ri+ht lobe is lon+er than the le)t- an! has an oval shape )lattene! in its antero,posterior !iameter The le)t lobe is i!eran! shorter an! has a trian+ular shape 5 smooth thin capsule covers the to lobes The lobes have a parenchymatousconsistency an! hite colour In normal con!itions- the thymus o) an a!ult male mouse o) three months o) a+e has anavera+e ei+ht o) =& m+

emo!al and examination.The thymus is the )irst or+an o) the thoracic cavity to be e*tracte! $ne o) the to lobes in itsin)erior part is raise! ith a clamp an! the li+aments beteen its in)erior )ace an! the pericar!ium are un+lue! ith the

scissors

In normal con!itions- the or+an shos variations o) !imensions in relation to the a+e o) the animal In )act- in the youn+mouse ";i+ 1B(- the thymus is ell !evelope!- hile in the a!ult or in the ol! a+e is atrophic an! !i))icult to !etectmacroscopically


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;i+ 1B Thymus observation

Size variations o) thymus are )oun! in some !iseases- ith particular re+ar! to localize! lymphatic lymphoma "thymic

lymphoma( In these cases- the thymus is enormously enlar+e!- increase! in har!ness- o) hitish colour6 sometimes- itoccupies a +reat part o) thoracic cavity In this case- the cause o) the !eath is the compression that the thymic mass

e*ercises on the respiratory movements

Sometimes- the investi+ator ill also observe the presence o) clear li:ui! in the thoracic cavity- an! the enlar+ement o) the

lymph no!es o) the thoracic chain


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3. )ungs and heart

Anatomical outline.The lun+s are to lar+e or+ans o) the thoracic cavity an! are compose! o) lobes The ri+ht lun+ o) themouse- li7e that o) all other small ro!ents- is lar+er than the le)t one This is !ue to the )act that the heart occupies- ith its!iameter- the +reater part o) the le)t thoracic cavity While the ri+ht lun+ is compose! o) )our lobes "the superior- the mean-the post,caval- an! the mi!!le(- the le)t lun+ shos a sin+le lobe

In normal con!itions- the colour o) the lun+ !epen!s on the amount o) air an! bloo! present- usually it is pale rose,coloure!The lun+s are elastic an! have a spon+y consistency

5 thin an! transparent serosa membrane- calle! visceral pleura- covers the lun+s 5t the level o) the me!ian all- inpro*imity o) the hilum o) the lun+- the pleura is re)lecte! an! covers the inner all o) the thoracic cavity an! then becomes

the parietal pleura 5 thin space is present beteen these to membranes "pleural cavity(

The heart has a pyrami!al trian+ular shape- ith its +reater a*is oriente! obli:uely to the le)t It is !ivi!e!- by the septum- in

one le)t an! one ri+ht hal) ith no communication beteen them 5n atrium an! a ventricle )orm each hal) o) the heart Thebloo! )rom the atrium +oes into the ipsilateral ventricle an! then into the circulation- either pulmonary on the ri+ht han! si!eor systemic on the le)t The atrioventricular canals are supplie! ith a valve that allos the bloo! to )lo )rom the atrium tothe ventricle- but not vice versa The tricuspi! valve lies beteen the ri+ht atrium an! the ventricle6 the bicuspi! valve is

)oun! beteen the le)t atrium an! the ventricle Throu+h the vena cava- the non,o*y+enate! bloo! arrives in the ri+ht atriuman! then passes in the ipsilateral ventricle Throu+h the pulmonary artery- the bloo! reaches the lun+s here it iso*y+enate!- an! it returns to the le)t atrium- throu+h the pulmonary veins6 then it +oes into the ipsilateral ventricle an!)inally it is !istribute! to all re+ions o) the bo!y throu+h the aorta

In the mouse- the len+th o) the apical,basal !iameter o) the heart is o) appro*imately / millimetres- hile its transverse!iameter- at the level o) the ventricles- is appro*imately ', millimetres

5 serosal membrane calle! the pericar!ium covers the heart6 the heart is o) re!!ish colour an! ei+hs aroun! 1=&m+

emo!al of lungs and heart.The removal o) all the thoracic or+ans "heart- lun+s- trachea- an! main vessels( must be

simultaneous ;irst- the oesopha+us an! main vessels "vena cava an! thoracic aorta( ill be cut ith scissors at the level o)the !iaphra+m ";i+ 1/(

Therea)ter- pullin+ anteriorly- the attachment o) the aorta to the vertebral column is remove! an! then- procee!in+ anteriorlytoar!s the nec7- the attachments o) the trachea an! the oesopha+us a7in+ another cross,sectional cut in the pro*imal

part o) the nec7- possibly over the laryn+es an! the thyroi!- the investi+ator can complete the e*traction This simpletechni:ue allos the isolation o) all the thoracic or+ans ithout causin+ any lesion or chan+es in their mutual relationships

5lternatively- the investi+ator may procee! to the separation o) the heart )rom the lun+s- leavin+ trachea- bronchi an!thyroi! in situ


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;i+ 1/ Lun+s an! heart observation

E*amination o) the lun+s .urin+ the e*ternal e*amination o) the lun+s- some particular characters ill have to be annotate!

accurately "shape- volume- consistency an! colour( an! their obvious variation

Partial re!uction o) lun+ volume may be observe! in atelectasis !ue to a compression o) a!


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The oe!ematous lun+ appears translucent- enlar+e!- an! o) pale colour- !ue to abun!ant li:ui! 5t a lon+itu!inal cut-per)orme! alon+ the +reater a*is o) each lobe- these characters may be better appreciate!6 hen you press the or+an

sur)ace- you mi+ht appreciate the loss o) !iscrete amount o) a clear li:ui! 5 similar picture is present in the case o)emphysema- here the lun+s appear e:ually pale an! abnormally e*pan!e! In this case cuttin+ the lobes is accompanie! bya thin crac7le- cause! )rom the abun!ant air comin+ out )rom the alveolar cavities

5 !i))use or circumscribe! enlar+ement o) one lobe may be an in!ication )or a !ia+nosis o) pneumonia In this case- the lun+

shos peculiar characters such as an intense !ar7,re!!ish colour an! har!ness similar to that o) liver parenchyma"hepatization( oreover- the cut sur)aces appear )inely +ranular an!- un!er pressure- a loss o) haemorrha+ic )lui! is

!etecte!

The presence o) some har! hitish no!ules easily allos the investi+ator to ma7e a !ia+nosis o) lun+ tumours a!enoma ormetastases(

emo!al of the heart.;or an accurate e*amination o) the or+an- the investi+ator must isolate the heart )rom the lun+s-

!elicately cuttin+ the main vessels usin+ scissors

The e*ternal e*amination o) the heart consists o) a !escription o) the e*ternal characteristics to+ether ith possible

variations- usin+ the same metho!olo+y )olloe! )or the other or+ans alrea!y !escribe! 0oever- !ue to the small size o)the heart an! conse:uent han!lin+ !i))iculty- the investi+ator- in the ma


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Chapter *

Cranial ca%ity

1. &pening and general o#ser%ation.

In or!er to complete the autopsy- the investi+ator must procee! to the openin+ o) the cranium )or e*amination o) the brainThe techni:ues use! are numerous- but e oul! li7e to su++est one that- in our opinion- appears the simplest )or a smal

ro!ent

Jeepin+ the hea! )irmly ith the ai! o) lar+e )orceps- the s7in must be cut ith a me!ian,lon+itu!inal cut )rom the nape to

the snout ";i+ %&(re)lectin+ then the to e!+es o) the s7in )rom one si!e to the other an! then pullin+ them toar! outsi!eso that the investi+ator mi+ht better observe the entire s7ull 5pplyin+ this techni:ue- the eyes to+ether ith the 0ar!erian+lan!s- hich lie in the orbital cavity behin! eye,ball ";i+ %1(- ill be !isplaye! ;inally- these or+ans coul! be e*amine!be)ore the investi+ator procee!s to openin+ the s7ull
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;i+ %& S7in openin+ )or s7ull observation


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;i+ %1 $bservation o) eyes an! 0ar!erian +lan!s

2. Eye

Anatomical outline. The eye- locate! in the orbital cavity- has a nearly spherical shape an! is connecte! at the bac7 to the!istal part o) the optical nerve

5 transparent- uncoloure! an! non,vascularise! membrane- calle! the cornea- covers the )ront hal) o) the eye The sclera-hich covers the posterior part o) the eye- is- o) course- not visible until the or+an is remove!2 it is opa:ue- hite- an!


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bri+ht The sensitive portion o) the eye consists o) an inner membrane- calle! the retina6 a nervous matri* that inclu!es the)inal part o) the optical nerve

The iris is locate! behin! the cornea an! consists in a circular !is7 ith a central hole calle! the pupil

The lens lies behin! the iris an! insi!e the eyeball It has a nearly spherical shape- an! is transparent- uncoloure!- o) an

elastic consistency an! occupies almost the entire ocular +lobe .ue to protein !enaturation- the lens mi+ht sho !i))erent!e+rees o) opacity "cataracts(

The cataract is a lesion that mi+ht spontaneously appear in an ol! mouse or as a possible late e))ect a)ter treatment ith

ra!iation 5ssociate! ith this lesion- atrophy o) the iris is sometimes present In this case- the investi+ator ill observe a!ar7 ra!ial strips aroun! the pupil to+ether ith the presence o) spots o) pi+ments in the )rontal part o) the eye In thea!vance! sta+e o) this lesion- the iris can be completely absent or ith the presence o) some pieces le)t an! locate! at thepupil e!+es Whitish irre+ular plates mi+ht be observe! in the central zone o) the cornea- mainly in ol! .@5 mice

3. 0arderian gland

Anatomical outline.The 0ar!erian +lan! "or retro,orbital +lan!( is locate! in the orbital cavity behin! the eye It is U,

shape! an! embraces the ocular +lobe at the bac7 Un!er normal con!itions- the +lan! has a +rey colour

Examination.The beni+n an! mali+nant tumours o) this +lan! are )re:uent an! they cause- in the ma


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;i+ %% $penin+ o) the s7ull


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;i+ %= @rain e*traction

4. rain

Anatomical outline. The brain represents the main part o) the central nervous system "CDS( an! it is containe! in thecranial cavity The brain has an ovoi!al shape ith the lon+est a*is oriente! in the s7ullAs cau!al !irection Three connectivemembranes- calle! menin+es- cover the brain The outer one is the !ura mater6 it is )ibrous- stron+ an! is in !irect contactith the inner )ace o) the s7ull6 un!er this membrane- a thin- transparent- invisible membrane- calle! the arachnoi!- lies

Un!er this one- the investi+ator can see the pia mater- hi+hly vascularise! an! intimately a!herent to the sur)ace o) thebrain


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The investi+ator ill then pass to e*amine the !orsal sur)ace o) the brain hich consists o) to lar+e hemispheres smooth- o)+rey colour- both separate! by one !eep lon+itu!inal channel The ol)actory bulb is locate! in )ront o) the hemisphere- hile

the cerebellum is localize! at the bac7 The cerebellum is compose! o) to small +rey hemispheres an! one me!ian lobe"vermis( place! beteen the to hemispheres6 it is covere! by thin convolutions

$n the in)erior sur)ace o) the brain- the investi+ator ill observe the me!ulla oblon+ata that is in !irect communication iththe spinal cor!

The pons- compose! by a hite nervous substance- is locate! in the cranial part o) the spinal cor! The optical chiasma- intohich the optical nerves en!- is visible more ahea!

In the youn+,a!ult mouse the avera+e brain ei+ht is appro*imately 4'& milli+rams

emo!al and Examination The openin+ o) the cranial cavity is carrie! out usin+ scissors that must be use! only )or this

proce!ure

The investi+ator ill ma7e a crosscut at the level o) the nasal septum- hich !ivi!es the to orbital cavities ;rom this point-payin+ attention that the scissors !o not penetrate the nasal cavity too !eeply- the investi+ator procee!s to cut the occipitalan! parietal bones ";i+ %%( 5)terar!s- the s7ull is remove! an! the brain an! menin+es can be seen ";i+ %=(

.iseases o) the menin+es consist mainly o) !i))use haemorrha+e )or rupture o) menin+eal vessels In this case- the presenceo) circumscribe! re+ions o) collecte! bloo!- usually in correspon!ence ith the a))ecte! lobe- can be seen

When the s7ull is completely remove!- it is possible also to observe partial or total brain enlar+ement as in the case o) !i))use

oe!ema or )or tumours

In or!er to complete the e*amination )or other possible !iseases- it is necessary to procee! to the removal o) theencephalon The techni:ue consists in raisin+ the brain by +ently intro!ucin+ )orceps un!er the )rontal lobe The nerves an!

the vessels o) the brain base are then cut an!- procee!in+ toar!s the brain base- the bulb is separate! )rom the spinal cor!ith a sin+le cut The encephalon is then remove! in toto- so that the cranial base can no be e*amine! ith particular

re+ar! to the hypophysis ";i+ %4( The investi+ator ill then observe the volume an! the shape o) this +lan! that- in normalcon!itions- is an oblate spheroi! ith its +reater a*is perpen!icular to the cranial base
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;i+ %4 $bservation o) the hypophysis a)ter brain removal "Clic7 on the ima+e )or a lar+er version(

With these manual operations- the investi+atorAs


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Once the necropsy has been carried out microscopical examination is required. It is very important that

appropriate pieces of tissue be taken and these sectioned in the most useful orientation. he follo!ing site is avery useful guide to blocking up and cutting tissues from rodents"

http"##!!!.ita.fhg.de#reni#trimming#$%F.htm
http://www.ita.fhg.de/reni/trimming/TR_F.htmhttp://www.ita.fhg.de/reni/trimming/TR_F.htm


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Mouse Necropsy

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