Univet·sity of Jordan Facult)' of Medicine

Medico! Ccmmi~tcc: Tile Univ~<-uity of Ja.rdon

lH[ lL§ tt<O> llco>g y . ~

D §Jhtecelt

ladl(es

D (Q)t]htceJr

lD)1r"' N a 1nnt •e: • F. ~raj. .Bustami ... . JDraute: .•.• • 26/6/.20:13. ...... .

- "" l~Jri.ce: .. ~4-.J .. b .. :

®

---.~.._ -.. - ~~blood vesXI_5 C'/7-K Tt LAG t: o ~I'MphiLfic;

n.erv~s Q, G~t~ 11 e c fl ·'.X( (7 ·ssl.A..Q_ tJ. ,tJ:- ~ 0v1 VI~ C§J

de..~1.Sf:.. ~ne.cn\J...e_ fl'ss~M. ~ ~t-~.

(a) Hyaline cartilage cells (chondrocytes) are located in lacunae, surrounded by intercellular material. (b) A micrograph of hyaline cart1lage. (X250.)

' ~ C 'l(i'V\.l ros f-t1 I C

- c KOV\. c:l r o b-€ns \:. '>.

- c-RcvJ..ra ~+0

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'tfou..f rJY

c. t.iJ. Vl( Sf

n'ssw (C-T)

~l c\ {y j ~ \_~() ~~"\ \ Y\1 e.r ce...Q,e uJ cl r 5VI.Io5r~

~---------------

~aun.cl subs+~~c~/---------~-~~~

~wSc\\V\; vt.o (GAG~) ~~----~~~~--~ ~

\,tJQ,_~ ..(Zr;y.,..,

rtsis t

.s

k ~rnfr1n SL-<..tfhrli(

Ch (!yt)rot'-h'n >:>

~--- ~~" W ,t:te_ r 'R..e.s i s-t ~ ress; (l)o\

Gttc;.s C{fyv, b i .,IZ..

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h:J rL~ U rOY! I c c2 u.'J..

d () 11 (J ~ /a, WI

Prot eo~c,lns Ynlt te.-t't t e..Vl a U. ~ ~ 'U::,

wit~ p;o-ftr'/.1 Cure. ft_~ Pro teo c..-rn s ( e -.3 Cl8J tr_JCrl ns)~ cJ'd _j{~i!)e. m 6-!e eu.Je /

C-<!""' f t'f.. Jf ,' o n 0. lAd o. c1: oV) 1 ;!t-er5 ctft1/nJ.t n-'' c r o (/-r.Jrl n /s u1s

·- -~--~-·--~-------'--'---- ·--·

c eJj 5 1'1 €_5€ ncl:Jw"J.._ eel}_ ---~ ~ ~~Jt---------'--"" f

c~6Y!cl ro bir1s-t<:.

~

-E---- HYALINE CARTILAGE.@

c::;;=-:-:-:::::=------=-------'_..-::::::;;;;;;:;:=-:-~"-------~· ~ Fig. 4.12 Hyaline cartilage. a Paraffin~ section of hyaline cartilage showing large

ovoid and polygonal chondrocytes (C) which secrete cartilage matrix (M)

(collagen and proteoglycans). The

perichondrium (P) is shown, from which,

in gro"ing cartilage, new chondrocytes

are produced by mitosis. Note that the

matrix is deeply stained close to the

chondrocytes, indicating concentration of

particular types of proteoglycans. r

- ·t (cf{G)1J. roiti n J ~j,U: ~J

~~r~· \

H :1 .,L-"-< 0;v...hi "(} t (f) ft.._ "'o st w i ~ J1 s tr i bu-t eJ ~~~--%--CM~hl-:-(w--e- ® ~ ~6'\SJ.¥- apter1rd ~ce} C ?

tJ-.t. ~o cu1..d. S'vtb 5-Hnc~ d6 {1...z rrvt11 tr/x ~ ~ S("J vue.. . ro(Y,Ff>' ve_ rrvle.x OV) -t},_,_ cdi'IJ'-1? a,J ~ dciSh'c tlf<e5 eVV\ lae_JdcJL fl'\ U · (i) Cavlll; f\ > ~ fe.. Jr ~CLJ erV\ W~t'~ KS i 5K frt--Ssu.r-t @ pO..s~ ~·c rwt~ fYtx{ fe_rrffdYI ~ h'tct tr/x W1 <N<.

Je.efJ SftlinJ V]ecv -tt~ )_flCUYtu_) {[) FERi CHoNDf(;U.M FRfSfNT 1N 1'105T PLACES. EXCE?TtoNS ~ ct.rn'culnr ettrfZP~ ¥ e.ri~~s;s ({) L-oCJ'Ih'6Y! ;o.)most- db fh_ st::J.e.J-on db ~s b) <uh'<-ul"-r e;;.. di og ~ iofll.t t ( OA 6 witr cNt;ir•j<)

c) no~ , ~~)( 7

Nr1ck1t 9 l5-rdY\c.~u· v/) vev1 N~ ~1./r 1; (t.b5

( Ul~tc~ CMtJ}.c~

r: bro CtM.-fJ (L~e_ J) ~ ~ 0 ~Jc(}k r)e.,v ~ S JrGVL\

den$-{ ~'(sro'vls h'S5lJ..R..~ w~

{a)-Fibrocartilage contains many large, collagenous fibers in its intercellular material. ~ -A'(sy 0 U {lf t5 d. i # -t-r Cfl h ·~Je . (f!Ju Ch.UYLdro"-hs+r ~·{rra er?.r~ .. btj~

£/J rf-vy fl'1.e J 2) C<J-.J..-hl in1 fyff. J ~fl~/11 t ~,·cft.t ~isH 1-enfio-.., 3) et0cA..6fWic ;v'Afr/')( ?;: 4) P~Ricl-/oNDi2tUM R@Sf!JT sJ LoCr1 h'or... ~ (i-;;te(ve rt( c

Pu..61'c Jy Mf J, s

c)

Found mostly in: -ex1ernal

ear

-epiglottis

C h. OYI..d to~i.-e5

wi~ ~

ctRJJ 0$~ /;;;/ @;· t-q,*-1. : '"··:-~.<. ;-' ft

' C~ v\t\(~ r o ~te s cl,_6Vlclfpren: (; 1 /)

ce_Us C~d.robtR5ts-MaP_ ceJ.Rs

--~~~~~~~ ~srinJR,- 'Wfe ctPJ.r Jm'v-eJ IIJ\<0 \\ o V or'!)_ '11\ ucQe .. as wi tJ i.'+fl e. 0j fayld..-:Jf'v, d'Lfu- CiM.fc1 i vt 5

\ OY81l"<l£t, fV\;n1s~;y Ay ?rot~i" l';j.,_"d"~;, . . .. Cow\ c{;~e_l'\ h,t.te_ u1 ro ct..cjvtcho (:,!.;ut-.. s 9/. o H-eo pr~j~5.

l_ct{,""cLob.tms) duivd e..it~ (ir6'MfjtW<eS.ut~~..,,f c~s w ; d r'Vl Jd 6VI cf r/ /c A fJ 'u'VI ce111 /Ve <JY @ (?(JYIA c ,.( (}Vl d r e(j CA 1 c

c U) $ '.~'~. tPJ.. ; II /11 ~ j ttij &!. c~ re. r/ c;: (JYt d r/ G(/A-1 l L i(_ [}.(

~f}So(~t'c c::Jnf8h•VI ( (Jroteir1 5(jntkst"s)

@o"t\Jro';jteSl ~ cbc~wGftJtSI:> ~t-trro<u.JJ {sy Mrl.luir.

cw,J ~·( wicl\iY\ l«cunr1C?..- (otty CiA.t.rYJ.dtofj~s ~ o.:c/r'v-t_ '-\A ?n;f~ .f'::)Vlt.P--V?/J ~u..f- cJ (clu ... cttcrv...choc_yf<:s-

lrt C.o--vv--t lvr"J c-t ch r u-( •

. rna-' . . . · .. usually ar-

.. • . ·•.: ., :. ranged in groups ·

Elastic

Fibrocartilage Type I collagen, acidophilic matrix, ondrocytes arranged in paral­

lel rows between bundles of col­lagen, always associated with dense regular collagenous con­nective tissue or hyaline carti­lage

most places. ~:.xceo-..P tions: articular carti­lages .and epiphyses

Perichondriu~

Penchondnlll9

. Articular ends of long bones, nose, larynx, trachea, bronchi, ventral ends of ribs

Pinna of ear, walls of audi­tory canal, auditory tube, epiglottis, cuneiform carti­lage of larynx

Intervertebrdl disks, articuiar disks, pubic symphysis, in­sertion of some tendons

··----. ------~-------------

~~ Jt:Ms<?.- -....p- c.o,h·(,J (~-.;- ... \ ~·-p- ?1"))

{] iJf1 ~ < S p (fl1 B (A ...,cJJ.o <As -"r -wtuL.Jl <::J 0 {i

(_ ~ tv<:_ WI. JlJ pq,,., uJ~

~ h'tl~) ~ &~s+e.u..wt ~

0 . WELL ~ ve.vtt.P. 3fSIArC"CJ

1i<:li>ccu1Jc ol cancellous L>one

FIG. 0-23 Upper ontl or femur cut c.Q_ronally"2!l£..~. ing(cnnc~~~:0a~d t:_~mp_ncl) llonl:n:lnd lllo ali[JnrnCiltOf bony lraboculac alonu line:; ol stress.

~- b ·. , tyi/. be. cul.a. <. C-.'\.v·, ti e.s e..rwe. '-'Yi

cf0 sf <{Y'-jj ba'vtQ. uYt--fc1 i Vi

~ bov- (._ 0'\1\ fl. rr c\N

M ed.di M.:J o~_ v r t:J r . e. C r\_ i) t f-.:) r/6 5 h ft « f-4Jy..}:,1 t'flJ 'I Jb;w b (/~

·'"Y\1\. r'\ r r c-w

~~; h'w Tv I 2jur:; ( 'jo\A f<.~ ~4~~ ~ ~ h!J(t. ru..~ec!c)q "\('ou<:>. b<..!~ ~!Ad;

ceJJs

@ ()SfcoY!fts . 'J

0'!JY!e. cd[s

,....,.......----Hydroxyapatite ...... crystals in ,.... parallel with ,.... ...... -: collagen fibrils ,

{(eYf6Y15J. f.tz ·~ JuvJ,tess ~ r i 8 1 cf..,'t~ '~ bdY!.e

® d_·. · .... --:· :·y,. """ "' '""' "'''•'=• · . · ----:-----=--· . ia called~

) ••••

0

, ~ • :. • : -,, , : .. 1 I.',· • ~'

® • . . · """:" Stacking of lamellae C"Ver ~. -· .. ·-... · _.· . ~ ...... Bone ~cqui!'es tbicl-.ne.ss by W&7 .. aAf · · ""' .... , .. ©

. · __ . _. . .. Between adjoir..i.ao la.r:::ellae .-:-:--:- · --....:. --:_. __..;... · · ~ there are spaces called

.". ·- · -. ·-•. -. ~$ ~ These spaces are

--~. ·:.~ ..... & .. · 7, ::;::;1hlhlllliJ" '""' •. £$:£_~:':

Fig. 7J Scheme 10 show how lamel/oe cons!ilulc bone.

.............. Osteocyte

cf•:·B> ~ . ~ ~--·-- --~.:' lacuna .

Bone marrow

Fig. ?.4 Relationship of osteocyte 10 lamellae.

®

7]w, f:Jf{ cb /J all.{ t~ cLfje) :s-;·. o':J_J !J<JYI. e'

-f 1 o ({,"1" if 6 (Jit ~' CfV\ fi_u_ 0 t/~ t_,t,j r -10_ Sf<l<es ~ v Vt d s ~111t - rk ,f<l ,cel~,w_ q,u_ <'LM ,, "'J (J a'} Cneet1i r t'c

f ( -.'L{ e S 0.. r o t·t vJ__ ct_ s l<IA .QQ. c <:,nty af2 cit " ,__Q ""'{> SIA.c /-.... UL

-~/l'on 1, b"'JJ1e 0 ecl)jeJ "'-- ~I V"r.rs/cln 5";t.N~n11 <fY @ J ff lfi] ' f?.e !w' e"' ftc,__ f.a_w. cJI II. ' -" -ti'W. <IA.t ~I Cu 11. ctt

~,,,;";if DfkoY:J le s) 'I ~J.. C<t~,J,. 'c,_L(,,( J<Ast a, ""' ~ fr,1 bew_{~,

CJ~ 5f(Yij,:} hoY1e_ - .t't wt_QJ_ ~~ be_ 5€~ U,LI:-~

@ {)k_ 5/ls IC srKucrutE a f If"":9j ~r-i eo.--y·7q b<f'vlc 0 -(;t.,__ s:tme t1-? --t!~ -.1-t.(_ botX <nA.-1d< (Lf ~ /t._,"'cef,te . ~ ho-ft ~fo;, ~ -.'!.) ~~J.. aJkoY:Jfcs """-j t/e_vi_ froc-me.--,

GJ -(:/_ ;;~l! £A ~ -[.t_._ 1-e/:u, ;,.,_ ct "' • u_., t '1, \5EL s lA Wt<1 h ,, ~-~~ ~ & ~ v roW s r Rc<.JJ- ""' s f1Jt<JJ J,(])-._,

-()~ f'Ylllitrr-oVJ SfrLce.s OCCVtf(j ?>\__ ?JrerL{f/1 c1Aec::L -ctvz_~ -{)u_ 6 6Yl<. f lA j, J f,L n c < 6 wf- ~ C;r.-.., (' <1 L/- bOY<, -u.,_ Sf'<l ( "-"

OVU- ~c:o ~W\~111 l (Je__/"'J Hjr&Jinl-~ (])\_~ (L:} tA-t_ HJl ~-e\: SiCl-•1 r{JI_ f"'l c,-{!2.t::

Osteon

Figure .J-1

CDHPACT BONE

Outer circumferential

lamellae

Cement line

Lamella

Haversian canal

lnn10r ~~-J-- circuml~renlinl

lameii<Je I )iagrt~nll1lilliL rcprc.:st:nl;lti~)n nr a cro~s ~L'L"Iinn l)r grtHIIld hllllt!.

Haversian canal

Osteocytes

Lamellae Lacuna Cement

Compact bon~ is found in the shafts of long bone~. In flat bones, it

forms two plates of bone, separated by a middle layer of spongy bone.

The structural units of compact bone ar~ called Haversian systems.·

Thesf! ere cylindricn.l structures tLJhose lon[J oxes are parallel to thG lo'l"t.J

---· ----------:------ --------------------·--------·-· 'f) (jJ) axis of a long bone. Running through the center of a haversian system

is a haversian canal, whi~h_contains_ blood vessels ~nd occasional nerves.

The haversian canals are connected with one another, with the exterior oF the bone, and with.the interior of the bone (the marrow cavity) by transve­

rne canals c~lled Volkmann's canals. The haversian canals are ~urrounded lm t:•.:t r, x.)

by i~:.:_~~~-ar material deposited in successive layers known as

c_C?~~ntr~-~J..~~e:..!..~.~~-~ Thuo,. each lnmella connistn -~f a layer of closely

pncked collagen fibers embedded in amorphous intercellular substance.

The osteocytes in their lncunae lie between adjacent lamellae. These cells

receive their nourishment ·from the blood vesnels in the haversian and

Volkmunn's canals by way of th~ tinsuP. fluid thut rermeates the canaliculi.

The ~s lyino between .the haversian systems nr.e filled

with the fragments of older haversian systems that have been partially

destroyed during the internal reorganization of bone during bone growth.

These frngments of lamellae are known as interstitital lamellae.

Surrounding the outer and inner surfaces of compact bone and, as ·

it w~re, holding the mony hnver~iBn systems together; there are a number

of lamellae called the outer ond inner circumferential lamellae.

SPONGY GONE.

Spnn11y (cancellous) bone is found ot the ends of long bo~-~~ and :in

the c-~-~~~~--.?-~~ln_~-~~'2~!:regular bone!3. :t is made up of_E._ranching_ . ~

t~<1b~culae, ~h of which is composed of EegularlX arranged .mn;el_§

Th~re are no haversiAn systems, and the osteocytes in their lncunae Are

nourish~d by the diffusion of tissue fluid through the canaliculi from

thr? mEJrrow cavity.

----· ·--- -------·----- ------Ex~mination of Bone

s: Oecause of the pres~nce Qr calcium salts, it is impos}ble to cut

routine histological sections of bone. Two methods are used to prepare

sections: (1) The bone is decalcified in an atid solution. The bon~ cnn

then be embedded, sectioned, and stained in the usual way. The osteocytes,

however, tend to be deformed as a result of the acid used. (2) The bon~ is

cut with a saw into thin pieces, which are then ground down bP-tween aless

plates with ebrasives. When a section is thin enough to be viewed with i3

light microscope, it is mounted. The structure of the haversian syst~m is

clearly visualized, but the cells are destroyed and the lacunne and

canaliculi are filled with debris.(

.,. ,<'""'""'\ Canaliculi {!JJ Haversian

canal

Locuno

Haversian canal ~

Volkmann's canal,~ (wllh blood vossol)

Outer circumferenlia~ lamellae '~

~ ~~J;':.Iii~H~IL __ Inner circumferential

Marrow cavity

Cancellous bone (spongy bono)

lamellae

, rt' ··u b 11 osteom, Lundlal', \'o/kmann's canals, h~,·ersiotn canals, lacunae, Figure 7-10 Diagram of bone illustrottmg comp;~ct co 1(, o e, can:lliculi, ant! sponbY bone.

I) 1'1. 0 t Ice. 1 11 ~ 't ~~.;- .. _? ~\~. -)'- /311)1 c. J.~!fl JJ,l_ e_ S hoW

· 3 ~ 'N·.<M : cl-t~X\'\ 'ill M c H~ 6.\1 CCI'\ ·tr 1 'c (J.s., IV\ 1' 1'-J oHt<MI ( 1-l~t ~~~ rs 1 ''"' S:JS~ Lwl) GJ ·r r rcj v,Lu /r"-,J rvtet\1J •'b

-Lv"' Jl;v.. (,.,.,(. .U •'* A:.u -1./;.!i... S f•l c t s k fW(.e..> 0-H-e.crvt r __..,.. \Y\~US.t\~A{ D'l'V\e)Q~c. ® Dultr o..v.d. -Ctls cl'lv<kyeJ \V\'1\Lf Cnt..A\1'\ {ci ... ef\h'rJ l~Vl;\JJIJ-c.

® V () J J\"" ,1 Yl ~ C '' Yl .c-f ? C'\ lJ ; '-::J ? V-? C~<.d ,' ev..&u, -f:o fk ~ () it '<-in o 1 +1.~.-t. ls-r·r~. t ....... c.-.-.."" v." '. c ,c,t c w; u.. H " vc r' i ,, " c 1\ \'\ "-~$

L ___ -_==:-__ --------------

0 Sflf:o pr o_je_n/t~• CW ( o5/egJ_-Ut/c. c.eJI)

~I @

~J_ijc'lfi.ol-1 _________ i hY\0\_ crJ.JuJ~'" )n.ye" i6 Pcrioste.u~v-~ UY\il'\j ~•LVQ..rs;fitl\. ctu",J~

\ ~ -te~ ~~ o~k.t.L\M ~ "t~e rl ved ~ """'- -r K""' b r ~ ~ ic. <"MtS 0>-1 ~ y /?1 e

~ C/tV\. u._ (I J e_r do M ,· h.J h ·c d. ,· u /s; t5'vl =1- ,g ,,_u,-e -tL'--Z_

fcrcfl~·rt)_ cf6 d-c(r6uef7h'rl.Hry ,/?r-o 0Sfeo/)r?Sts ----7- Sp; r.) if_ s-l-..,~ I f6 cJ_y ci ~~-u~re/ (:_ E ((_ a; &ole;}. ~ MaH c,{ uh'~·.z du.rt'r;j Per/oj cl'!c ittl-e41.Je. ~~?. 'f}tott/ti

~--.__...,.---...--....._---- .... __./-· __ .-........ _. ---... ·

(o s leob.Ra()t s] ~d_e_n've_J /YoYVi OSf'e U"frOy{n/{-oY ce_j_[s

~ re:>e~m~i·U-~ -hy _S~nmJ"i5 ''b rtf'-{_ OY()(Uir·c ~(lcFVlfnl-j' ~ 15-o'Y\.l!_ f)\1\C._ tr l 7< r f1 c fA" eli;:; C ~ c( e n ¥ fro k ?!J1J (,-1

11 s

~ }1 ( tt h' ul'\. ~ 0; r ~ ct ({_ 6b ~'b~ cy-. C/t. p ( i . Q c rJj\.-M(l fY ~ __ ?_~V7~"F·wJ_; c; ~~(M"" ~ ~ f\ ~- r Vlv---;:-;]t_,?; r C i z--r; ___:OY-I'J'l-~'Yl-t:.--r(-(-.e__-----f-h'iY-S~-r::•~Y\.......___----,.._

CW '"YV\.-tMA\s-!'11'\( ·~ W~ f'cvv7..-t/.v--rr 0 ~J._ ~C'vW\,'V\~ ~lr-ds 1/0 ~ rtCC-ffV\.s ~ Lf- Stirr.,_,~.l.n:fs o51tot-f?Uf-f ~ ~ ~-e_ G(e.___b_ 0 S f-{'o c lr?J+.- S'n'Mt/t.lz il'!:} f?. C{-Tt. t.,Jit/c~

0_ G\ ch' v rLt e s o s k. o c Ins 1-s --trJ e [50/?./?. /3 0)) C. ~-=----------------------,__-_____ __.,..

. - ·- ·---------·

(!e c_ ef/-tff Q hy @51 eo cl -'H s;;"' .J,Hl ";}- ~nhr'l J ~ -n·W\ vi. Me baYl~ K s Olph' o;rv,

C .,.Q u ·hV'\ I V\ j n ~ ; b ; 1: r b ~ ________ V"'-{ .S (fy f f) crv.

\~ ()(.'l+i 6V\ }+ 0 CC"'fj <::hJ.R UW ~ rf Sf; <~.s, "'1

b uY--t. S vlr~ue c .-JJ.. ed H 0 uJS H 1 P s 1acu._na<

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RecQ_U ~ o~feo~ctH cfb boY-R.

~ ctJJ 'YY\ewt bY(1~e ~ invo-t.~J \ n b oV\..(_ te...c; CJr f h · <I'n.

n (fY W1 ~ . u~ (/.) 0\ b~t'lV\. (f ktw e~ \ 'o/ oSko\las+- aUivitJ ~ ~· cJ\ieA.-J.Q WULSJ_ \

rtYVI AirtJ C(Jvdfr111f- Y f~ Nut~'€A ~s.£ t\f (fY I

---.. d c"'\ ( V\ _.. ~ bcfV\..{ lJY\Ct fJ4. 'YV\..L-lu.te foov..e 0VI.<?Vn ~ ~~

/

Nucleus

p~~ Golgi \!:;:,,:.~::·:~;.) ~~·~v

Nucleus ~

611/ ~;,;ed_j

border -~

Bone matrix

Section of circumferential clear zone

Figure 8-5. Drawing showing some aspects of osteoclastic role in bone resorption. Lysosomal enzymes packaged in the Golgi complex and hydrogen ions produced are released inlo the confined microenvironment created by the allach· ment between bona matrix and the osteoclast's peripheral clear zone. The acidification of this confined space facilitates the dissolution of calcium phosphate from bone and is the optimal pH for the activity of lysosomal hydrolases. Bone ma· trix is thus removed and the products of bone resorption are taken up by the osteoclast's cytoplasm, probably digested further, and transferred to blood capillaries.

1\IECHANISi\1 OF BONF. RESORPTION. Within osto::o­clasts, til..: ..:n;.vmc earhonic anhydrase c;ttalyzes the intm­L·ellular fonn;tion or carbonic acid (H~COJ) from carbon dioxith: atH.l wat..:r. Carbon it: ac:id is unstable and dissociates within the cells into H+ ions and bicarbonate ions, HCO.,-. The bic:arbonate ions, accompanied by Na+ ions, cross the plasmalemma and enter nearby capillaries. Proton pumps in th..: plasmal..:mma of the ruflled bonier of the osteoclasis ac­tivdy transport H+ ions into the subosteoclastic compart­ment, rcuucing the pH of the microenvironment (C 1- ions follow passively). The inorganic component of the matrix. is uissotveu as th..: environment becomes acidic; the liberated minerals enter the osteoclast cytoplasm to be delivered to n..:arhy c:apillaries.

Lysosomal hydrolases and collagenase, which are sc­c:r.:tcJ by ost..:oc:lasts into th..: subostcoc:lastic compartment, UC!,!radc the organic components or the decatc:ificc..l bone

111 ;:trix. Th..: t.kgrac..l;ttion prnducts are endocytoscd by the: os­teoclasis anu further broken down into :.~mino acids, mono­~:tccharides, anu disacch:.~rides, which then are released into n~:trby capillaries.

0$ S / f/ Crt h';~ ::;::-~ ( llouc Foru~iou)

Bone develops by rc lacemcnt of a pre· existing conm.:ctive tissue an , epen tng · upon the type of connective tissue replaced, two modes of bone formation can be rccog· <2. J 17 1 0 nizcd. If bone is formed directly in a primitive , -?> G-4\cto C0-<5Y\..C{I-.M

1, V\ t r il rn L W1 b Y" rll'l Cl \A S ~

0 $$ i ~· CtLh'C/)'o

connective tissue •. the process 1s called intr~- 0 5 S i l· cil..h" membranous oss1Jicauon, whereas when 11 ; P lfYl

~ occurs by replacement of a preformed carti· ; laginous model, the process is known as en· !

. dochondral ossification. The essential process ·.1 of bone formation is the~ in both types,' J however. -=- :l

lu l ramcmiJruuou s Ossi!icul ion

KEY WORDS-ostcoprogcultor cells, os· tcoblasts, ostcocytcs, os·; teoid ~

The bones or the vertebral column, pelvis. extremities, race n1H.l bnsc ol"thc skull dcvch1 1

by formation of bone in a cartilaginous mol el wh1ch must be removed bdore bone can be laid down. Endochondral hone formation in-

The l1at bones of the cranium and part of; valves both removal of the cartilage model the mandible of the face develop by intra·.) and deposition of hone matrix. These pro-membranous ossilication and arc frequently ccsses are most conveniently studied in a long

®rcfcrrc~ <o :_'_"'cmbrancboncs ~At tk l:o~:~ w~ /MeMG,,t.,, bo>At

· ... ,;._ -f7_ 1.. [l_ __ w..(d. e -ct C/r1.vt"Je.1

mtSE:Il c:J,_CJ'M.J ~ (!)0{!){0)(!)(0)@:··· Ooteobluto · VJ \,'\,) ~ (OY J

1 { ___, - ~--· :~~~!;.:\i-.roo c eJJ;5 Gf ~< C losef:J.. fticKeJ i/, tiuL 0"\11.. UJ Cv1 c ~ rv.. ,J!. -b' l s (,....( &< ((l'M..(. );,..,~ v if.? Cu..(~

..

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Osteoid (Coll•c•n !ibr••

embedd«-d ic · s•l• tinoue zr.atru)

e (0) (0) (0) 0 B@) a Oatoo1d 1 { _ - - - .... conYeorttd iato ~·

~ - lemellua or bone @

@ 0 co;) (0)@@ ceJ@) @).··· Ooteoblut zl· ·;-. . " ... · . .- ,: :::;;<," ••• Oohoid -::.m.....:·· ~ ,,

I -- - ' .... ::- -·· Bone - -' ..

® ~0(0)@0@ ~~ .

J \'~···. · .. · .:.!.:· .... -·. · .. :'."":~ ·Third le1H :. •• • 1 • :.~ · · : ot osteoid

~ - - -·· SotoDd lam•llua 2 . -~ _ ••••• Tirot loe~ollua

I -- --- -

Fi&· {.K Formation o_(bony lamellae.

rvl (/) lM chV!A. J cf.)) s -} d.; /1 tA. t Y1. fi ttle .----'-'1.__,/-o,.....,-os.p_oproj-Lrr/foY cdls It :J\0Jt~(l{_,(r1Jtj

'I f} , -f. 11 • J. I OSfeotJAOL5h Sec;-c;:te ().n (ll.XC.i {l(ol

t/vl rl {-r i x C rJJ ecf 0 S {:(. o i J{ff} vJ l. /ct. _j_;Lt e.... freL.tJ""(r (t\.A//cJ lr:J dtfost'h'Cf¥\ ~ C,L+t

S' ,ll.,t .s LLn d.v.. ·tiv... ~c)_ 1, eLf_ fC.. ;]_-< ,vU!

piVJJf)M:.rl.U e.-nr::p,.n<. KJ.e.i/.S(d 0:J Q$(-<.ob.lots

As . ~ ltte.ns . .t~ e.r d(; ostco)/ \;t ~5 CfY\.t ). rlm dJ. W? o'tJ ~-<. © / \---------------------~------~--------------OY i?A ~ _tl rn eJ} vi a 1'1 o -te..~ f_ZJ.-.;t_ e.A cf6

(JJ te...o i d ' w l.tl i J.. d. (j\J,.}() V-:i f),;..(_ 0 5f e () b/r1 st 5

7-h. .. 0 S{e.o Ua5f:s 'lYlatc cl. vJ itj ffJW\ -th. ).N·.-.elJ. (.V) to i...I" r1 e. i1.. ~ !H w bJ e.r ci7.J o5te.oi&--)>- ;-tow<.vU~. S'trrv~c '?, ~ fJd C.tVlf <- (,<. N e e.vt tf..-z. /. flVVl. dJI.,V-J U ~ o Hto.iJ. -r rh< ostco/d V.J noW c,J. c./he) -to .fluw. r\ "'ott.. e.--.. LrlWlJJ!c-fJ ~ Th cc}Js

fritPfeJ. /.;<.twe~ ~ l-vJo .f.ILrvte}J.Ite G-t~ o5teoua-tes

'*'

Dip ln.: (~poll}!\' bon<:)

lnm·r rahlc· or lfiiii)':IC( btlllt."

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I. Carlilago

modo! -----

--1a\, laaell"a

' "-.

Periosteal collar

·: .1 ..... :··

coll

-Calc1!1od JCAtri ·,

··Empt7 epoc• · (Pri.m.ar1 aroclu6)

earti.laga

&r or .. calc1!iod """tTl~ .

, I

. Fig. 7.15 End<>chonclr.>l o"ilica1ion: '~'~"in (orm.-Jiion o(bonv l.:Jmcll

CD The-rrrsti-nciTciitions-of'oss.iiication arr~.:ar in the center of the cartilage model in the region destined to become the shan or di­aphysis. In this area, called the pri111ary ossi­fication center 1e chondroc tes 1 ertro 1

and thei c to lasm hecomes vacuo atet T 1c lacunae enlarge at the expense of the sur­rounding matrix anti the cartilage between ad'acent lacunae becomes reduced to a thin, fenestrate partJtton. e cart1 age matnx re-­maining in the vicinity of the hypertrophied chondrocytes hecomcs calcified hy the depo­sition ofcalcium phosphate. Diffusion of nu­trients through the calcif"led matrix is reduced and the chondrocytes undergo degenerative ch~~~e_s leading to their death.

@C:oncurrently:-the-pericho,1clriunl-at- the ~i'cfri-rr~ the diaphysis of cartilage becomes vascular­ized (Fig. 7 -17). When this happens, cl:ondro­genic cells become osteoprogenitor cells forming osteoblasts, and the overl}ing perichondrium be­comes a periosteum.

@The newly formed osteoblasts secrete bone ma­trb:, fonning the subpedosteal bone collar on the surface of the cartilage template by intramem­branous bone formation (see Fig. 7 -17).

@)The bone collar pre\·ents the diffusion of nutrients to the h)pertrophied chonclroc)tes within the core of the cartilage model, causing them to die. This process is responsible for the presence of empty. confluent lacunae forming large conca\ities- the future marrow cavity in the center of the cartilage model.

@Holes etched in the bone collar by ostcoclasts per­mit a periosteal bud (osteogenic bud), composed of ostcoprogenitor cells, hemopoietic cells, and blood vessels, to enter the concavities \lithin the cartilage model (see Fig. 7 -15). ·

@Osteoprogcnitor cells di\icle to form osteoblasts. These newly formed cells elaborate bone matrb: on the surface of the calcified caztilage. The bone matrb: becomes calcified to form a calcified cartilage/calcified bone complex. This comple.\ can be appreciated in routinely stained histo­logical sections because calcified cartilage stains basophilic, whereas calcified bone stains acidophilic (Fig. 7-18).

f"i~ 7.1H fo>rmallnn or lypicnl lonij hnne:=

pcriuslc>l coll>r.

---A

I

> Secand11r1 oenlrea

nony { epiphy•••

1

D

®~. 1 . I , .· ·t" I hone hl:'comcs thKk~• ,\ncl

7 ,\~ tw ~'''ll''"l~L·' .... r 1 , ,;.0\\'S in each dirL•clion !'rom the nuLln!.l . o l :~e

Ji<lphysis to\\'<Utl the epiphysl's, o~teot·h~ts begm resorbin~ the caldRed cartibge/~·,tlCIFied ~~ne .com-

lllex eniar~rin" the marrow ca\1ty. As tim ptol cessl

·' " " I f 1 1· }l'·sis is rC[l ·\cec continues, thL' carti a~e o t .'e c i<\[l ,. ; :1 . I h,· hone l'XC'C\lt for the C[Hphyscal prates, \\ \lC I

· . ·'I . !'Ill' tilL' conliliHL'Li ~rm\·th of the :11"1' l'l.'~jlOIISI I ~ '

hoi\L' !'or I I) lll ~ll )'L'ars.

FVI·::"TS occVHHl:-.IC A'l' SEco:-.IDAin· CE~'>-. TEI~S 01' 0SSIFICA'J.'ION. Scconcla.t')' c~ntct·s. o[

ossification begin to form nt the l'[ll[l~'Y~'s at e.l~h cllll of the funning bOIIt' hy a process smHbr to th.\l

in the diaphysis, exce t that a bone collar is ot * fonnccl. Hnthcr, osleoprogcnitor ce s invndc the cnr­tffi,gc of the epiphysis, differentiate into ostcobbsts, and begin secreting matrix on the C<lrtilage scaffold (see Fig. 7 -15). These events take place and pro­gress much ns they do in the diaphysis, and eventu­ally the cartilage of the epiphysis is rephlced with bone exec t at the nrticular surface and at the e i-* physeaJ ate. 1e articu ar su ace o c:art1 agmous throu~hout life. The process at epiphyseal plate, w'hich controls bone length, is de­scribed in the ne.xt section.

TIH'.~t· l'\'l'nts arc n d)11amic t·ontinuuln that is c01npleted O\'L'r a ll\llllhe;. of ye<lrs as bone gro\\'th nnd dt•\'cllljllllL'Ill P.ro~ress lm\'nrd ~~-ll' gn:\\·i.~l_t; epiph­\'Sl'S al t•ac:h end ol lhl' bone (sl'l' I able 1 -..>). At the ~;\lilt' tinw, the hone is constant!~· being remodeled to 111eet the ch<lnging forces placed on it.

The continu~d lengthening of bone depends on the epiphyseal plate.

The chonclroc)tes of the epiphyseal plate prolifer­ate and p<uticipate in the.' process of endochondral hone formation. J>rolifL·ration oct·urs at the epiphyseal a~[lt'l't. and rcplaeement by hone takes place at the diaphyseal side of tht· plate. l'listologic:ally. the epi­ph\'St'<ll plate is dhided into he recoanizable zones. '!"!{est• zones, beginning at the epiphys~al sick are as follo\\'s:

Zone of. rcset·Ye cnt·tilagc: Chonc,lrocytes ran­domly distriuutccl throughout the matrix are mitoti­c:allv active. z?~C of prolifcmtion.: ChondrOC)tes, rapidly pro­liiPJ'ntillg, fonn ro\I'S ol lsog<'IHIIIS cell~ thnl pnrnllc•l tl1L' dirl'ction of bunt• ~ruwll1. Zone of malurution ·~IIlli hypertrophy: Chondru­c~tcs mature, h.'vertrophy, ;mel accumulatl' glyco-gen in their C}toph1sm (see Fig. 7-16). The mattix lx·twccn tiH.'ir lacunae narro\\'S \\ith a correspond­ing gro\\'th of h1cunac.' .

... Zone of calcification: Lacunae become confluent, h~11C'I'trophiecl chonclroc)tt•s die, and cartilage ma­trL~ hl'comes calcified. Zone of ossification: Osteoprouenitor cells in\'nde the area and differentiate into

0

osteobbsts, which C'lahorate matrix that beconws calcified on the sur­f,,ce of calcifil'd c<~rtilnge. This is followed by re­sorption of. the calcified cartilagelc<1lcified bone complex.

•hu,ro......rl·: br t.hla lmct.h ·· ·

' I ,• ::·•.,.j

·rnu· rrrlnn h .. I be.n. ror.t"d b7 : proll.rerat1t'I'D of" cart11u• cella ·

4 ,. 1 ·, • • : ' ;J ·.~ '~., ~i j:::\

.. "'

As lon•r as the r:tte of mitotic acthit:y in the zone of prolife~ation equ:ds the rate of resorption _in the zone of ossification, the epiphyseal plate rem:uns the same 1\idth and the bone continues to grow longer.

Fis. 7 .2.2 Growlh in !eng~ or bone 1.1 epiphyseal carti~ge. · At ahcn1t tla• 2llth _1·ear of :1gc. the n1te of mitosis dl't"J"<'a.'t'.\ ill lltL' /.Cllll' or pro)if"cration <llld the zone or o~sificalion con·rtakt's tht• zonl'S of proliferation and carlil:l:-:<· rv't'IYt'. Till" cartilage of the epiphyseal pl:tte hecnlllL'S rl'pl:tccd h~· a platt· of calcified eartila~e/ calcifit•d hulll' complex. ll"hich become~ resorbed by os\C'oelaslie ;Jdi\·it~·. and the marrow ca\·ity of the diaphysis ht·t'Oillt'S conflllt'nl ll"ith the bone marrow ca1·itl' of tlw L'jlipl1_nis. Once tlw eli lhyscal llate is resorhl'd. <..:ro\\'th in lt•twth is no Oll"t•r l l ·s· •. ·--no."\E, GROWTH I~ "'IDTH. The e\·cnts just descril>nl dl'lail !tow hotiL' lenglht•niug is accom­plislll'd l>y the proliferation and inll'rstitial grm1·th of cartilage, which is t·l·enlually replaced by bone. Growth of the diaphysis in ~irth, however, takes place hy appositional gl"Owt.h. The osteoprogeni­lOI" cells of the osteogenic layer of the periosteum prolifer<tlc and diffen•ntiate into osleoblasts that ht•­~in elahor:tling hone matrix on the subperiosteal bone su rCtce. This process occurs continuously throughout the total periotl of bone growth and de-

?

f"iF. 7~1 Sta<'~' in fu'i"n t•f cpopli)..i' ~ootl tli~ph)>h. CAJlloofu~tl: tllll'•nully lu,c.J: ll"J J"u,c.J.

®

®

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©

®

6!ii:::\. Por1o•t····lb.on·-­

~ E:ndocboa4ral boa•

a a"for1

La1•r Z dopoaitod;

Endochondral bon• re11o'led to fora &.arrow c•T1t1

0 Lo.;ror 1 ro1>0ud

•• Lo.1•r Z

-La:ror } dopoo1tod

~~::.: :·~ud

~~er ~ dopoaitod

OLa;ror ' roao~•d

••• La1•r It

'Lt.711" 5 dopoaitod'

\·elnpment. so tl1at in a mature long bone the shaft is built 1·ia s11bpcriosteal intramembranous bone form;l­lion.

Dming l>one gro\\'th and development. bone re­SOJVIion is as imp01tant as bone deposition. Forma­lioJI of lo1111<' ctll IIH' Cllll,idt• of tltt• .~lnd"t lllll.~l bl' :lcCulnpanied IJy osteoela~tit: activity internally so tl1:1t the marrow sp:tct' c:m be enlargcJ.

Figure 7-14 Light mkm~ruph of intr:l11lt'11lhranooos ossificn· tinn (X 13~). Trabeculae of bonL" ;\r~ bdng foruwd br ostcobla.sts linill'' tl~<~ir surfan· (nrrocn). OhscrY<~ ostt•or,tcs tra' ctl tn lacunae iarn~du·w/ . ..,_} l1imiti\'(• ostl'llllS arP h~..·~'illllin~ to onn

CONVERSION OF SPONGY BONE TO CO~! I' ACT IIONE

':i:AII new!~ formed bone is spongy. This is converted lollows(hg. 7.10):

into compact bone as

)~~ /. ........ , . .

/ ;(IV·~~:~· ... ~:: ~ ·, • 't\l·Ooteobl.,t, llnlnc

. _ ...._ • , • .• : • • • • , •) I 1na1de of -.pae•

~~·;?~·

Fig. i.IO Convenion or~pongy bone to compact bone.

lamcllu~ of hune aflcr an0thcr inside each space. As they do so the space becomes smaller and sm'lllcr until it is reduced to a small canal carr\ in!! a few blood vessels. This canal is surrounded by rings o~ cuncentricall) arranged

l:tmellae. Thus Haversian systems (or osteones) arc formed, and the spongy bone becomes compact. It must be emphasised. however. that the lirst formed Haversian systems (primary osh;oncs) arc :1!\'pical in thr cumpt,sition and· arrangement of the bony layer.; that constitute them. These arc soon eroded to lorm a new scncs ~>f ~paces that arc again filled in by bony lar:1cllac that constitute typical Haversian systems (secondar ostconcs). This process of'} !ormation an cstrucuon o osteoncs ta ·es place repeatedly and goes <>n even· * after birth. This provides a method for reorientation of the oste.oncs to suit the

. d hb ~ ~~ stresses 1m pose on t e one. :"-· ~ ....

'(fjj'''""'"t·!·•········--

4

- ••• ';~~ ~;i~ -r~~i 1~-~ ~~ . '

.· ..... ' -

.

1 centrea I

I

Bony { opiphyeeo

1 I I I I I

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I I

I ©

Fig. 7.19 Fcmnation of typical long bone: Secondary centres of ossification. -~-=-==..c-===-------- ------------ - -- . 7 ({) H ik ~ &cllM.. --'?nn.0s~~t.~c:&·iVV~e.{~ ,

l.j ck- o'; h . .., ""'' "" tk -f s u.r f,,c <- '1_ oH:e o G-eal; d.e.ri wd , c'V!A ost-c:..oproje flr't-e.rr ce_(f /n. -d.Q_ /1111.eA.. f.r~er

c!G f<LrtoSfeL{'N\ (f) bu'N. rf,f(('(p(l~rY\ CJY\ ~ inner Jv'lf rlC~ JG ~ ~ln.~t.fJ{: 'i(e,.me_ VVl ber ~re r/J Ot W<''IJK\?_

be.lwe.t..v, --u.~ CA.Ch'vr'-t_y d6 OSfe.o~rts<:s(h(JVI.Jz_ epo~i~~~~ 9) ?S-k.oc.1.rH't.s ( b~~ l'eJ6Lfh~) ~ ct {~ WfltACe &; cltS1-v.rbeJ l·e b6'11\._q_ ~50Lpn·O'h > bo~ ~s/h~ ~

0 s_ho p~)r 0 s i_r ( etc~~€- -~. b_"': ."':'C\ _ss) ~

( 1) Early in intrauterine 11 fe, the bone is first a model of ® cartilage. Then a primary ce~tre of ossification appears in

the middle of the shaft + (this occurs towards the end of the

8th week of i.u. life) from which bone is laid down. At birth,

the shaft is bone while the ends are cartilage. In X-ray film the shaft will be seen while the ends will not. T~art of the_bone

which developed from the primary centre of ossification is called

the diaphysis.

{2) At a definite age af.ter birth, a secondary centre (or

centres) of ossification appears at each end transforminQ it into

bone, The part of_bone whi~h developed from a secondary centre of

ossification is called the epiphysis.

(3) ~~~~?f-~physeal csrtilage -z::::-~ - ._.

is left between the

~,\ phy&i-'" ~~~ri dtt\rhys:t&·. lhlO nU.owt:J rur Llu~ growth or bone in

length. The port of the diephysis which is adjacent to the epiphysecl

cartilage ls called the mRtRphysis. It is the site of advancing oss­

ification.-

(4) At a definitP- age, ossification encroaches on the epiphyseal

plate, and union occurs between the epiphysis and diaphysis. As a result,

growth in length stops nnd the bone is said to be an adult bone.

( 2) In long bones, with ~a~n~e~piphysis at each extremJ~, the end et

which THE EPIPHYSIS FUSES LAST AND OSSIFIES FIRST

is called THE GROWING END.

N.B. The fibulA is An exception to this rule in that its lower

epiphysis osaifiea first hut joins thP. shAft before the upper epiphyo1s.

3. The chief nutri£?nt ArtE?ries nf the bones of the upper <md lower

limbs ore directed reopectively toward~ the elbow and ~a~om

the knee i.e. AWAY FROM THE GROWING ENDS. (From the knee I flee,

to the elbow I ga (or grnw).

4. Growth in length of the bones of the upper end lower limbs takes

place chiefl.La..L_the epiphyses ~J:Eh.j_oin the shaft last. The

growing ends thus ore ot the ~~~nd of _the humerus, the l~_end

of the~adl~s and ulna,the lower end of the femur and the upper

onds of th~ t\bi~ nnd {ibul~.

-----~~.-- --r 1 y ':1 (t?fi~ {{ ( " ~"-~(.~ (~ Fl\ 1S

~ ~-tt.. WtcK cf'b c\t

i {1-trtutu dte

"

........ ·---------------The humerus : oaa1f1e~ in cartilage. It haa a primary centra for the ehert cppaar1ng nt about the Ath_we~k of i"tra-uterine 11f~. At th~

upper end, a aecnndarv centra appears during ~~ 1at y~~~~~ ~he heed,

!_1")~ _ _3_!d yeer for the .s_r~eter _B.Jbero_!i_i~ end the 5th yea~. for _!!1,g,·

1o~ tuberosity. Thaae_l_c~~ ruee by the~~~ and the whole

,g_p):p_h_y_e_le_ fu~~..B..:lllJ th __ the sheft4-t eb~_20 ~eara. The lower end has

!._o.!-!E.-~~F.QD..d.~ry cen~, two app~aring early (for the capitulum together with the lateral half of the tr~~trlee· -'at 2 'leers 'and for the medial

e&c.£1l!!Yl.E~~~a) end ~o ap·p•arin~-~! (for the rest of the trochlea at 8 yeara end for the lateral epicondyle at .10 years)

The lateral 3 centres fuse together at about,1~ years and join the

ah~ft at about 16 years. The medial epicondyle joina the shaft

independently shortly afterwards.

.\ I I I I

·.· .. . ·· •' \

.... "

;pf~~~·s~!i ··~~

. . ..- ::~ -· .

A

. '':

'_;

;,i. ' i

' calcifying cartlla . . ge----_.

,, .... '.

Bone marrow

, Osteoblast--

.;

. Osteoclast _____ ---ld

. Osteocyte

~. e ""·

rest' · ang cartil (R..,e.se..r·~ age V'- )) )

prolife~tin g cartilage

hy ~ pertrophled . . .j, '"'"'"' caJcifyin ( /?.Lu.:) ca•~•

bono trabecul

(NnK- ,etrj) BI>oogy b one

~ g e.

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1,:. ~ ~I

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A jc;,"~ V? t)..J_ @ W {A.u.e_ fwo ()(

Ca~t. fo.Je{lv?.r ~ -{:~ &.-fWeet., ~ ·

(-~--~----------6) 5_jV\cN i

~~ f\ \" -h'~i\r S \J\ 't' ~ tlcc:.

0 1"~"- Crt_fSvJ.~ C4

W ~,._~·c.(.,., d.oe..s 4~ ~; ~\.,_;~

·!