Differences between growth sites and growth centres

DIFFERENCES BWDIFFERENCES BW
GROWTH SITES ANDGROWTH SITES AND
GROWTH CENTRESGROWTH CENTRES
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CRANIAL GROWTHCRANIAL GROWTH
CENTRES –CENTRES –
FACT OR FALLACYFACT OR FALLACY
--KoskiKoski(AJO1968)(AJO1968)

 The termThe term growth centregrowth centre has beenhas been
widely used with skeletal growthwidely used with skeletal growth
phenomena to the extent that it hasphenomena to the extent that it has
been used to cover up many growthbeen used to cover up many growth
sites.sites.
 Baume-Baume- proposed that the term skeletalproposed that the term skeletal
growth centre can be used to describegrowth centre can be used to describe
places ofplaces of endochondral ossificationendochondral ossification
withwith tissue seperating forcetissue seperating force..

 Time factorTime factor is also brought into considerationis also brought into consideration
wherein growth centre should mean a placewherein growth centre should mean a place
where the growth of a skeleton takes place for awhere the growth of a skeleton takes place for a
sufficient lengthsufficient length of time to make aof time to make a realreal
contributioncontribution to the increase in skeletal mass.to the increase in skeletal mass.
 BAUMEBAUME also definedalso defined growth sitesgrowth sites as regions ofas regions of
periosteal or suturalperiosteal or sutural bone formation andbone formation and
modelling resorptionmodelling resorption adaptive to environmentaladaptive to environmental
influences.influences.
 KOSKIKOSKI has tried to examine some of thesehas tried to examine some of these
alleged growth centres using the definition givenalleged growth centres using the definition given
byby BAUMEBAUME as the criterionas the criterion..

Growth centreGrowth centre
 InherentInherent genetic potentialgenetic potential
 Independent ofIndependent of environmentenvironment
 ExtirpationExtirpation
 Resemblance toResemblance to epiphyseal plateepiphyseal plate

Epiphyseal plateEpiphyseal plate

Koski studied the following areas-Koski studied the following areas-
1.1. SuturesSutures
2.2. Cranial baseCranial base
3.3. Nasal septal cartilageNasal septal cartilage
4.4. Mandibular condylesMandibular condyles

SUTURESSUTURES
There are two schools of thoughtThere are two schools of thought
regarding the growth at suturesregarding the growth at sutures
1.1. Sutures areSutures are 3 layered structures3 layered structures having twohaving two
layers of connective tissue seperated by a singlelayers of connective tissue seperated by a single
layer of connective tissue. The connective tissuelayer of connective tissue. The connective tissue
layer acts as the proliferatng zone. Implies tissuelayer acts as the proliferatng zone. Implies tissue
seperating forces in the sutural tissue.seperating forces in the sutural tissue.

22.Sutures are.Sutures are 5 layered5 layered with the 2 bones onwith the 2 bones on
either side having 2 layers of periosteumeither side having 2 layers of periosteum
with a 5with a 5thth
intervening connective tissueintervening connective tissue
layer.layer.

 Question is whether the growth is primary orQuestion is whether the growth is primary or
secondary in nature.secondary in nature.
 EvidenceEvidence in favour of dependant rolein favour of dependant role appears toappears to
be accumulating-be accumulating-
1.1. Trabecular patternTrabecular pattern
2.2. Removal of suturesRemoval of sutures- little or no effect on- little or no effect on
growthgrowth
3.3. Shape of suturesShape of sutures- functional stimulus.- functional stimulus.

4.4.Closure of suturesClosure of sutures- determined- determined
extrinsically.extrinsically.
5.5.External force applicationExternal force application
6.6.Parrallelism of suturesParrallelism of sutures- superficial- superficial
-zygomatico-maxillary sutures-zygomatico-maxillary sutures
-direction of growth varies-direction of growth varies

 ConclusionConclusion
-unlikely that there are tissue separating forces-unlikely that there are tissue separating forces
-they are unlikely to be growth centres.-they are unlikely to be growth centres.

Clinical implicationClinical implication
 Split suture -RME.Split suture -RME.

Cranial baseCranial base
 Cranial base synchondrosis especially theCranial base synchondrosis especially the
spheno-occipetal synchondrosis has beenspheno-occipetal synchondrosis has been
considered to be a growth centre.considered to be a growth centre.
 Evidence in favour-Evidence in favour-
1.1.structural similaritystructural similarity to epiphyseal plates.to epiphyseal plates.
22.reaction to.reaction to biochemical stimulibiochemical stimuli similar tosimilar to
epiphyseal growth plates.epiphyseal growth plates.

Cranial baseCranial base

 Evidence againstEvidence against
11..no tissue seperating forces.no tissue seperating forces.
22..transplantstransplants

ConclusionConclusion
 There seems to be no direct evidence toThere seems to be no direct evidence to
support the claim that they are growth centres.support the claim that they are growth centres.

NASAL SEPTAL CARTILAGENASAL SEPTAL CARTILAGE
 The general concensus – nasal septalThe general concensus – nasal septal
cartilage provides thrusting force tocartilage provides thrusting force to
carry maxilla forward and downwardcarry maxilla forward and downward
during growth.during growth.

ChondrocraniumChondrocranium Relationship of theRelationship of the
cartilagescartilages

 Evidence in favourEvidence in favour
11.. endochondral ossificationendochondral ossification -is seen.-is seen.
2.2. vomeralvomeral--edgeedge -is an area of proliferation-is an area of proliferation
3.3. on palatalon palatal –surfaces resoption on nasal and–surfaces resoption on nasal and
deposition on oral side.deposition on oral side.
4.4.excisionexcision
5.5.arrhincephalic patientarrhincephalic patient-normal vertical-normal vertical
-retarded saggital mid-retarded saggital mid
faceface

Deficient growthDeficient growth
Deficient growthDeficient growth

11..excisionexcision-retards growth (may be due to-retards growth (may be due to
trauma, early excision does not affect)trauma, early excision does not affect)

 ConclusionConclusion
May be a growth centre in post natal life.May be a growth centre in post natal life.

CONDYLAR CARTILAGECONDYLAR CARTILAGE
 There is a general belief that growth at theThere is a general belief that growth at the
condyles moves the mandibular body forwardcondyles moves the mandibular body forward
and downward and this opens the space belowand downward and this opens the space below
the cranial base into which the mandibular andthe cranial base into which the mandibular and
maxillary processes grow and teeth errupt.maxillary processes grow and teeth errupt.

1.1.StructuralStructural
- Is a- Is a secondary cartilagesecondary cartilage. Latecomer, not. Latecomer, not
even from the same precursor as the aseven from the same precursor as the as
epiphyseal cartilage.epiphyseal cartilage.
-Does-Does not grow interstitiallynot grow interstitially like epiphyseallike epiphyseal
cartilagecartilage but appositionallybut appositionally ..
-The-The cells that divide are the intermediatecells that divide are the intermediate
layerlayer cells and not cartilage cells, these are likecells and not cartilage cells, these are like
undifferentiated mesenchymal cellsundifferentiated mesenchymal cells
--Structural organizationStructural organization is lackingis lacking

--non hypertrophic cartilage cellsnon hypertrophic cartilage cells-the layer is-the layer is
very narrow and change into hypertrophic layervery narrow and change into hypertrophic layer
very soon.very soon.
-the whole-the whole hypertrophic area seems to be inhypertrophic area seems to be in
aa state of mineralizationstate of mineralization whereas in thewhereas in the
epiphyseal plates only the degenerative zone isepiphyseal plates only the degenerative zone is
mineralizing.mineralizing.
--spongiosaspongiosa always seen in long bones isalways seen in long bones is
lackinglacking

 2.2.FunctionalFunctional
 Resposive toResposive to mechanical stimulusmechanical stimulus
 Respond differentially from epiphysealRespond differentially from epiphyseal
cartilages tocartilages to various hormonal and chemicalvarious hormonal and chemical
agents.agents.

3.3.TransplantsTransplants
only whenonly when
transplanted withtransplanted with
adjacent bone does itadjacent bone does it
grow, but even then thegrow, but even then the
structure is notstructure is not
maintained as beautifully.maintained as beautifully.

 4.4. Tissue culture studiesTissue culture studies
demonstrates lack of cartilage growthdemonstrates lack of cartilage growth
 5.5.SurgicalSurgical
bilateral condylectomy shown to have nobilateral condylectomy shown to have no
appreciable effect on the growth.appreciable effect on the growth.
 6.6.ImplantImplant
direction of growth seems to varydirection of growth seems to vary
considerably. sometimes upwards andconsiderably. sometimes upwards and
backwards and sometimes upwards andbackwards and sometimes upwards and
forwards.forwards.

 FINAL CONCLUSIONFINAL CONCLUSION
The existence of growth centres have not beenThe existence of growth centres have not been
demonstrated beyond doubt. We should keep andemonstrated beyond doubt. We should keep an
open mind and look for explanations andopen mind and look for explanations and
theories that agree with all well known facts.theories that agree with all well known facts.

Thank youThank you
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Differences between growth sites and growth centres

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