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In the last 2 lectures we took about the skull, and we divide it into the

cranial part and the facial part.

Last lecture we stopped at paranasal sinuses , we said that we have 5paranasl sinuses ( maxillary,frontal,sphenoid,ethmoidal,mastoid) and we said

that all of them open into the nasal cavity except the mastoid.

Today we will start with new topic which is more important clinically and it

called the skull fractures.

When we speak about the skull fracture, we divide the fractures depend on

the fractured bone, so we have fracture related to the cranial bone and

fracture related to the facial bone.

Now, the cranium of the skull (cranial bone) also is divided into:

1) the cranial vault (the roof &the wall).

2) The cranial base.

SoSkull fractures

Cranial bone

fracture

Facial bone fracture

Cranial vault

fracture

Cranial base

fracture

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So we will start with the fractures that usually happen to the cranial vault

(calvaria).

Before we start, you have to know that the skull itself is built up to resist up

these kinds of fractures by 2 things:

FIRST : convexity of the skull

when you look to the skull ,you can see that it has rounded shape ,so when

you have a blow on the skull ( la sam7 Allah ) the force (due to the

convexity of the skull) will be distributed into waves all over the skull ,by

these we will minimize the effects of the blow.

SECOND: the buildup of the skull itself.

If we look to the skull, we will see that it is made up of 2 tables of compactbone (outer & inner layers of compact bone) and there is layer of spongy

bone between them.

So, why it is made up of 2 layers of compact bone (diploid bone which is mean

duple layer of bone)????

these usually happens because if you have a very large blow to the skull,

these will lead to fracture to the outer layer , but you need another force

(power) to fracture the inner one

these is another way by which the skull will resist the fracture.

SO REMEMBER THESE POINT

**the skull will resist the fracture by 2 ways

1-the shape of the skull (convexity of the skull)

2-the tables formation (diploid bone)

However, if the force is so strong, it may lead to fracture in both tables.

The fractures that happen to the vault of the skull, it is usually classified

into 4 or 5 kinds of fractures.

1) The most common one we refer to it as a linear fracture.

As it is indicate, these fracture will go into a linear way (like line,

LOOK TO THE PICTURE),

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2) so the blow to the skull usually

comes from a very fast object

(like small stone), these will

lead to a fracture which is

radiating

in both direction (in a linear

way).

THESE THE MOST COMMON KIND OF FRACTURE THAT USUALLY

HAPPENS TO THE CRANIAL VAULT OF THE SKULL (CALVIRA)

NOTE: if the suture separate, these separation is considered linear

fracture because the suture is linear also.

2) the second kind of fracture is caused by very heavy and large object ,

so when it blows down over the skull especially in a thin area ,it will

destroy the skull ,and make it to be impressed inside ,and these

also lead to further harmful to the under Neath soft tissue

( like meninges and brain) .

This kind of fracture called depressed fracture,

because the bones have been depressed inside to the cranial cavity. OK

NOT THAT COMMON

3) Comminuted fracture

what dose comminuted mean??

it is mean : kind of complicated OR there is a several segementes

so ,in these case the object is large and it is very fast so it will lead to

fracture of the skull into many small

fragments

-so , it is a strong blow & it will lead to

fracture of the bone of the skull into

several pieces

AS A REVIEW

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until now we spoke about 3 kinds of fractures :

1-linear fracture

2-depressed fracture

3-comminuted fracture

4-NOW , the forth kind of fracture usually happens to the cranial wall in

area called pterion area and we called it pterion fracture .

What is the pterion???

It is the weakest point in the skull, which is distinguished by H shape suture.

if you look to the skull laterally , you will find that there is apoint

where 4 bones ( frontal,paraital,greater wing of sphenoid ,

temporal ) meet together and forming 5 different joints

or sutures .

so these area because there is so many sutures , if someone have a blow

on the lateral aspect of the skull ,these will lead to separate the sutures

( THE MOST COMMON KIND OF SEPARATIONWHERE YOU HAVE SO

MANY SUTURES) .

So it is a very dangerous region of the skull, why??

1) The point of weakness (because there is so many sutures that isresembling the shape of the letter H.(LOOK TO THE PICTURE)

2)another thing is consider very important in the pterion fracture that is

the

largest meningeal artery which is providing blood supply to the meninges

called middle meningeal artery .

these middle meningeal artery enters the skull through foramen spinosum

and then it will be distributed into anterior branch and posterior branch.

The anterior branch is just directly passing to the internal surface of thepterion and it is even grooving the bone.

NOW, these artery in the pterion and the pterion very

common area to be fracture , so if there is a fracture in

the pterion directly there will be injure in these artery.

Pterion

**It is agreek word that is meaning

a wing because it is close to the

greater wing of sphenoid.

**it is located about 3 cm above

the midpoint of the zygomatic arch

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Now, if this artery is injured,

these will lead to severe bleeding

(because it is from arterial source) these bleeding

we refer to it as EPIDURAL HEMORRHAGE.

So after injury there will be bleeding ,and then accumulation of blood the

fractured site( bone) and the meninges.

NOTE: epidural hemorrhage for all artery that are supplying the meninges

,the most common artery 80% to be injured is the anterior

branch of middle meningeal artery

because the most common fracture happened in the pterion .

NOTE: the most common reason for the epidural hemorrhage is motor

accidents (car accidents).

NOW .What is happing there??

if there is a severe bleeding the blood will start to accumulate there

,pressuring the meninges , and in turn the meninges will pressuring the brain

,so if there is no drainage of these hemorrhage quickly the patient will get

into coma within just half an hour and within hours (2 or 3) he will get intodeath.

So, those are the fractures that affect the calveria:

1-linear.f 2-depressed .f 3-comminuted .f

4-specific one which is the pterion fractures.

THE FRACTURE THAT ARE EFFECTED THE CRANIAL BASE

Those fractures are further classified into 3 different parts dependingon the location.

As we know the cranial base from inside made of 3 fossa :

1-anertior cranial fossa.

2-middle cranial fossa which is butterfly shape.

3-poserior cranial fossa.

Hemorrhage : bleeding

Epi: above ( outside)

Dural: referring to the first

layer of meninges, because this

artery is located between the

meninges and the skull bone.

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NOW , if there is a fracture in the anterior cranial

fossa

**if the damage happened to the cribriform plate of

ethmoid

so the cribriform plate of ethmoid actually opened into

the nasal cavity ,so if these

part fractured and also lead to tearing in

the meninges ,it will cause kind of bleeding there , so the blood

come from the brain all the way down into the nasal cavity

then to the outside .

These we call it EPISTAXIS.

epistaxis mean: nasal bleeding .

Causes

More than 100 causes

The last common cause eno there is a fracture to the anterior cranial fossa.

So, the epistaxis doesnt only relate to the anterior cranial fossa fracture

(any nasal bleeding called epistaxis) .

But if you have severe blow on your skull, and then you find a nasal bleeding ,

you have to put in your consideration there is a possibility of fracture in the

anterior cranial fossa.

The more common thing to find a tearing of meninges , YOU KNOW that

there is a fluid between the meninges and the brain , these fluid protecting

the brain and act as shock absorber and it is called CERBROSPINAL FLUID

(CSF) .

y Note :Cerebrospinal fluid (CSF):

y -cerbro: from cerebrum y -spinal: from the spinal cord

NOTE: the cribriform

plate of the ethmoid is

perforated to allow for

the olfactory nerves to

pass through it down

into the nose.

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y We can define it as:y A clear colorless fluid, that comes from the filtration of the blood.y -consider as A PLASMA FLUID.

So if there is a tearing of meninges ( sometime due to just a fracture to thecristagali ,so if it is fractured ,it will injure the meninges)

once the meninges injured ,there will be a leaking of CSF into the cranial

cavity, and then through the perforation of the ceribriforem plate of

ethmoid to the nasal cavity .

So if someone came to you with an accident , and he has a severe blow on

his head ,and you see that there is a colorless fluid leaking from the nose

that is mean there is a CSF leaking & that what we call it CEREBROSPINAL

RHINORRHEA .

What dose rhinorrhea mean ???

It is mean rhinenose (iam NOT sure about the spelling)

Mean filtration of the CSF.

the third thing thing you going to find in the anterior cranial fossa is the

EXOPHTHALMOS .

exophthalmos : is meaning the bulging of the eyeball anteriorly outside the

orbit .

The exophthalmos indicates that there is a fracture in the orbital plate of

the frontal bone, when there is a fracture the blood will leak into the orbit,

so there will be a blood accumulation into the orbit and this accumulation will

produce a pressure, and this pressure will push the eyeball outside.

SO, AS A REVIEW

Those are 3 different signs for anterior cranial fossa fractures:

1-epistaxis (nasal bleeding)

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2-cerbrospinal rhinorrhea(CSF running from the nose)

3-exophthalmos (bulging of the eyeball outside)

FRACTURE IN THE MIDDLE CRANAIL FOSSA

The most common fracture in the cranial base happened in the middle

because it is the weakest part of the base of the skull due to there is so

many foramina and canals there .

NOW, if there is a fracture the CSF will not leak through the nose, it will

leak through external auditory maitous.

NOTE: petrous mean ROCKEY.

These bulging inside the temporal bone actually happened because within it

there is the internal ear and middle ear.

So, nerve to the inner ear come from the brain then pass through the

internal auditory meatous to the inner ear.

So if there is a fracture in the middle cranial fossa and there is a leaking in

CSF , the most common area that the CSF will pass through it is the internal

auditory meatos then the inner ear then middle ear and finally the external

ear opening to the outside .

So, when you see patient have a leaking of CSF from his ear: that is mean

these patient have a fracture in middle cranial fossa.

Note :

As you know, there is a connection between the external opening of the ear

and the middle cranial fossa called INNER EAR OPENING (INTERNAL

AUDITORY MEATOUS) which is located in the petrous of temporal bone.

*petrous part : huge elevation within the cranial base of the

skull this part covered the Internal and Middle ear .

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The nerve of the inner ear comes from the brain and enters the internal

Auditory Meatus and go to the inner ear

IF there is a fracture on middle cranial

fossa there will be an injury to certain Cranial nerve ( 3rd,4th,6th) these

nerve arise from middle cranial fossa and passing from there to superior

orbital fissure to MOVE THE EYE BALL :)

Very Important nerve which is the largest Cranial nerve 5th Cranial nerve

with its 3 branches Maxillary ,Mandibular < supply the upper and lower

teeth > and Opthalmic branch .

Maxillary nerve pass through foramen rotundum

Mandibular nerve pass through foramen ovale

IF there is a fracture on middle

cranial fossa , the most common

site for leakage of CSF is ear ,

also there will be an injury to

certain

Cranial nerve

( 3rd,4th,6th) these nerve arise

from middle cranial fossa and

passing from there to superior

orbital fissure to MOVE THE

EYE BALL :)

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Opthalmic nerve pass through superior orbital fissure , in this case of injury

of the trigimnal nerve the patient will have paresthesia in his upper and

lower jaw and lips .

When you have a fracture in the middle cranial fossa this Cause leakage ofCSF from ear, paresthesia in the upper and lower jaw and lips , cant move

your eye ball .

Complicated fracture we cant notice itdirectly because the bleeding will accumulate

On the back of the neck and covered by

posterior muscles of the neck , the blood will

accumulate between the bony part and those

muscles it will take 24-48 hours to indicate

this accumulation , this injury will go to the

nerves that come from jugular foramina

( 9th, 10th, 11th) nerves .

Always the facial bones are small and double so its gonna be a single bone

fracture or complicated one complex ,, involving more than one bone.

Single fracture in facial bone commonly occur in the Nasal bone , or mandible

Posterior cranial fossa

fracture

Facial bone fracture

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*If you have any bony fracture that involve soft tissue damage *

Complicated facial fracture :

Le fort use to drop the skulls from a roof of

a high building then he go and analyze the

pattern of the fractures so he find that the

fractures happen in 3 levels of the weakness

in the face so he called them :

Level 1 = le fort 1

Level 2 = le fort 2

Level 3 = le fort 3

y Level 3 : the most dangerous one

Le fort 1 :

Called transmaxillary because it

passing in a plane crossing the 2 maxillary bones , if you took a lateral

view you will see that the fracture going all the way to reach thepterygoid process of the sphenoid bone.

Le fort 2 :Passing through the sub- zygomatic *zygomatic bone is above this

plane.

plane involve several bones , other name is pyramidal because as you

see its going in pyramidal shape in this case floating segment

unstable segment will involve Nasal bone , Lacrimal bone , Maxillarybone and may posteriorly involve thepterygoid process.

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So ,, in le fort 1 all of the alveolar process and the teeth will drop

Down.

And in le fort 2 the pyramidal fragment that involve nasal , maxillary

and lacrimal bones will drop down.

le fort 3 :which refer to it as suprazygomatic but more correctly we will say

about it CranioFacial because whole of the facial skeleton of the face

will separate from cranial bone , this fracture involve Zygomatic,

Maxillary , Nasal bones .

single fracture :

most common in the nasal bone !Why ?

prominence in the face ,, if you fall down the first thing you gonna hit

is the nose small and tiny plate of bone

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y The fracture of the nasal bone itself not severe condition but we getafraid from the complication that may be occur in this case.

the complication happen if the fracture extend into the frontal

process of the Maxilla which contributing on the middle wall of the

orbit

*Middle wall of orbit : frontal process of Maxilla

lacrimal bone , ethmoid , and the body of sphenoid

y The second complication is the injury within the frontal or ethmoidalair sinuses

* because in the frontal bone we have frontal air sinuses behind the

nasal bone down there is ethmoidal air sinuses.

Although the mandible is the strongest bone of the facial skeleton but its

the 2nd bone to be fractured , Why ?!

* Movable bone ( only movable bone in the facial skeleton)

1. Condylar fracture : most common because of the narrowing in themandible which mean less amount of bone , less density ,, easy to be

fracture especially when you have a hit to your chin when your mouth

is open ,, nothing to support the mandible only the area of the TM

joint ,, so after the hit the whole mandible will go backward however

the condyle fixed in TM joint , ones the mandible go backward the

condylar neck will fracture

2. Body fracture : common fracture if its happen usually gonna be in the

canine region because :* canine has the larger root so the larger socket less amount of

bone- easy to fracture .

* convexity .

3. Angel fracture : 1. Posterior downward

Mandibular fracture :)

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2. Anterior downward .

*What is the difference between them ?!

downward backward : dislocation of the whole ramus superiorly .

on the outer surface of the ramus there is a muscle called Masseter

muscle that arise from the zygomatic arch and one from inside which

called Medial pterygoid , if the mandible fractured at the angle region

the ramus will go up by the action of these 2 muscles

* superiorly dislocation of the ramus .

Forward downward : no displacement the body of the mandible will

prevent it >

4. Coronoid process fracture : the largest mastication muscle inserted on

the coronoid process of the mandible so it will be superiorly

dislocation by the action of the temporalis muscle .

What you have to do due to the fracture ?!

mandible is a ring bone passes in 2 sides if you have a fracture in one side you

expect to find a fracture in another side may not be there but expect that

and look for it :)

so we have to see all sides of the mandible you need complete view it mean

you have to use panorama x_ ray the best way to diagnose the fracture in

the mandible because it will show whole parts of the mandible from side to

side another , when you look to the picture you should pay attention to 2

important regions 1. Cortical margin

2. Mandibular canal

you should follow them to discover any discontinuation which will indicate a

kind of fracture .

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y forgive us for any mistake !y best wishes ,,

HAYA MOMANI ,, HEBA RADIADEH :)