CROWTlI AT FACIAli SITTURES

INTRODUCTIOS

A T THE: present time much work is being carried out on the methods, sites, and patterns of growth in the human face.l+ j This knowledge is of

fundamental importance in the understanding of the etiology of malocclusions and facial deformities. Certain conclusions, however, are of doubtful validity. as they appear to bc based on an inadequate study of the mrthods of suture growth and the precise arrangements of the sutures in the facial skeleton. It, is the purpose of this article to investigate and discuss these matters.

GROM’TH AT SUTURES

The structure of growing and adult sutures has been described by Pritchard and his associates.” They have shown that a typical facial suture (Fig. 1) is composed of five layers of tissue between the bony margins of the sut)urc. These la.yrrs arc :

.I. A cellular layer belonging to each bony unit. 2. A fibrous le,ycr continuous with the fibrous p,eriostrum

covering each bone. 3. L4 central layer, containing blood vrsscls and unitiIkg

strands of collagcnous fibers.

Growth at a suture takes place at. each of the cc>llular (cambial) layers and may differ in its intensity and amount for each of the bones. The relationship of the bones to one another, at a suture may be (1) an edge-to-edge relation- ship (Fig. 2) or (2) an overlapping relationship (Pig. 3).

If the relationship is of the edge-to-edge variety, growth at t,hc sut,ure is correlated with separation of the bony elements. Growth may take pla.cc at t,he sutural surface of one or the other of the bones or at both. The process may or may not involve a change in position of the suture (Fig. 2). Tt is im- portant, moreover, to know whether or not. the suture changes position, as WI’- tain sutures or points on sutures arc often taken as “fixed points” in super- imposing ccphalograms in serial studirs of facial growth.

Tf, howevrr, the rclat,ionship is of thr overlapping variety, growth at, the suture ncc~l not involve scparat,ion of the bones. With surface deposition, one boric migtxtrs over the surfacc~ of t,hc other and the position of the snt,urc

From the Anatomy Deuarhnent, Queen’s University.

381

.I. II. s~:o’I”I’

3 ---- D D 1 A, 0. c. D. E.

Wig. Z.--C:rowth at an cdgc:.to-mlge suture : <aross-hatclling shows new bone (lcpoaition. h’, Bone is deposited at each sutural clement: tlw bones move apart but position of the suture remains unaltered. C? and D, Bone is deposited at one or the other of bony elements and 0x1~ of the bones moves so that position of the suture is altcr’ed. H. ~onc deposited at one bonr only, upper bone is fixed and lowrr bone moves ~lomnward whilfl position of suture rnnains unaltere(l.

q--- - - -

1

Q

-w-w- -

b

Fig. S.--Growth at an overlapping suture. Wit11 cleposition of bone on the surface. but not in the suture. one bone migrates upward over the surface of the other and thr, suvfacr position of the suture is altcred. 1. (kipinul position : 3. na9v Ilosition.

C:lW\\;th at SntUrYS does llot in itsdf produce sep:Wation of t,he bones at tt1v sntuw. This is brought, about by the growth of other organs snc>h as t,hc (*;\rtilagc ot‘ the chondrocr~anial and chontlrofacial skclcton, the l,rain, the cyc- lmlls, and t,hc tongues

The snturcs of the craniofacial skeleton can hc grouped into a numhcr of sntut~c systms. The sntnpcs making ~1) each syst,elll are SO arranged ibs to pclrnrit growth in a certain direction. ‘l’hc suture systems in t,he human fac:cs 2l.W :

1. The sagittal sutu~ system, made up of the mid-palatal, intermaxillary, internasal, and metopic sutures with the mandibular symphysis. It is co111-

l)lc~tc in f’ctal lift and at birth, and permits growth in width of the facial skclc- ton. At the end of the first year. the tnandibular symphysis and the metopic~ srIt,ut*ch in the ma,jority of persons have united. and the sagitt,al sutnrc systelrl is no longer complctc. It is donhtfnl whcthcr :rny further growth takes place in the mitl-palatal suture after this time. By the end of the first, yea I*, the dis- titllcc l)vtwcvn the Iwo orbital caritics across t,hc bridge of th(h K~OSC has ~a~hc~l nctnlt tlimcnsions in nmny children.

Fig. 4.--Uiagram to show the position of the maxillary and craniofacial suture systems. Sotr relationships of frontomaxillary to the frontonssal suture and of the posterior border of the maxilla to the palatine bone and pterygoid plates. N, Nasai bone : E, ethmoid (orbita Illate) ; N, sphenoid (including pterynoid plates) ; Z, zygomatic process of maxilla.

2. !Z’he mazillar~ slstuye system, macle up of the sutnrrs separating the t~~;lxiIla from the nasal, frontal, lacrimal, facial cthmoitl, palatine, zygomat’ica, ant1 ~~omcr bones (Fig. 4). This system consists of two limbs, a horizontal ]ilrlb at the medial and lateral walls of the orbital cavity (including the votrrerine-maxillary junction of the nasal septum), and a vertical limb in the ptcrygopalatine fossa (hetwcen t,he maxillary and palatine bones).

3. The cmn.iofacial s&we s@em, made up of the supramaxilla.ry and 18~1 ro~naxillary facial bonc~s on one side (nasal, lacrimal, facial et,hmoid, pa1;1-

Of llll, ItlilXillit.

Fig. 5.-Diagmrn to show the position of the zygornatic and palatine bones retativc to the maxilla BS seen in a transverse section. Arrow indiratrs position of nasal septum and the direction of growth of the maxilla in early childhood. Plate) ; Pt., pterygoid lrlates : %u~I.. zyaornatic bone.

Pal., L’alatinc bone (vertical

b’ig. 5 shows in ii tlina.t’;ttttttt;tt,iC ntantt(‘t’ the relationship of the palatine :lntl zygotnatic bones to the tnasilln its SCW~ itt a horizontal (transvcrsc) stdion of the t&c. .It will 1,~ SPOIL that the v~rtid plittc of the palatine l.)on(~, which fot’tlts part of th(a sick wall of the nas;tl cavity, OY(~~IRPS the back part of the nasal SLU+‘:MZ of the ttlitdll:t. ‘I’hc two overlapping l~oncs bctwecrt them form t,ho boundaries of the grciltct’ palatine canal I(1ittlitlg frortl the l,tct.ygop,?Intillc fossa above to the greater palntinc foramcn on the palate bc~low.

The zypotnatic hone nrt~iculatzs with the snrfacc~ of’ the zygomatic princess of the mnsilln which facts natww.rd and slightly forwit rd.

Fig. R.-W’ontonasal and frontonmxillary sutures in a child of 6 years and in an aclult. Note the higher position of the frontonasal suture in the adult.

tll(’ /‘t’OtltOlttil~illi~~~ Slltllrt’. ‘I’h(s sutl~t*~~ Itct\v(~(~ll the ttasitl ittttl f’t*otttill I)OI~CS is 01’ thcl ctvc~rlapping nt riety antI ItilSiOtl :ISWII~~S 011 the ft*otttitl It(ttl(J with ;lg~. This cillt lte sho~~t ils ~OIIOWS :

I. Nasion is usl~itlly closcbt* to thtx llppct* ot*bit;~l tttitt’gitl itI ttdlllt, ~l<nll~ th:rn in tht ~l<lllI~ of childtm.

2. The ftY~lltOll~lSill SlltlltT iii ildllItS is llSll~lIl~ :lt, Lt highct 1~~1 than thtb frontotnasilla ty sutnrc. In cdhiltlt-cn! the t\v(l sutures ilr(l ;tt ith(tl~t the satllc ICVCI (+‘ig. 6).

::. Iii sagittal Sertions, the direction oi the frontortasal sutllW is Sppn to 1’1111 ~~]~\\ritt’(I illIt OUt\V;llYl for SOlllC cliStilll(~(! he-

foty it ~.lltms fot*w;t rtl. N;lSiOll in tllc, iltllllt is llSll;lll~ SOIIIC t]ist,;l.tl(~c~ ;ll)o\(~ thtl Icv(~I of thta rtlt)f OC the lla~al cavity (etil)riEortt1 plntc). In cahil(lt*cn it, is at almut the siltttt: lovcl (Fig. 7).

Therefore, the position of nasion cannot be taken as evidcncc of separa- tion of the maxillary and frontal bones and it must be used with care as a “fixed” point in the superimposition of serial ccphalograms.

Investigators sometimes treat changes at the posterior surface of t,hc maxilla as seen in lateral cephalograms as evidence of sutural growth. Dia- tnond4 pointed out that the posterior surface of the maxilla grows into the pt,erygopalatine fossa throughout childhood and adolescence and does not be- come buttressed against the pterygoid processes until adulthood. Furthcr- more, the alveolar bulb of the maxilla projects backward on the outer side 01 the lateral pterygoid plate and undergoes a p~~ccss of altc~rnating cxpatlsinn and contraction as the molar t&h develop within it and move forwaI,tl into

B’ig. ‘I.--Diagram of a sagittal section through the front of the nasal cavity to sho\r the upward migration of nasion relative to the roof of the nasal cavity. N, Nasal bone; F. frontal bone; E’, ethmoid ; Na, nasion.

occlusion.7 Therefore, growth at the posterior border of the maxilla dock not necessarily involve growth at the deeper palatomasillary or palat,opt,erypoid sutures.

Each suture has two growth sites, one for each of the bony elements. Growth at a suture may or may not involve a change in position of the su- ture and may or may not involve separation of the bones. During early child- hood the maxilla is thrust downward and forward from the anterior segment. of the cranial base, but this process of bodily moremcnt of the boric is not brought about by growth in the sutures. The separating force is provided by growth of the septal cartilage and the orbital contents. The position of nasion and the posterior border of the maxilla, as seen in lateral cephalograms, cannot be used as direct evidence of sut,ure growth with scpn.t*ntion of t,hr bones in the analysis of growth chnngcs in the maxilla.

REFERENCES

1. Hjiirk, A.: Facial Growth in Man Studiell With the Aid of Metallic Implants, Acts, odontol. scandinav. 13: Y-31, 1955.

Additional Reference List The following references should be atNed to the ;Lrticlr entitlrtl “Care ol‘

the Deciduous Teeth as t,he Basis of Occlusion of the Permanent Dentition” by l~curnan 11. Laugh (AK J. ORTHODONTICS 41: 90-106, February, 1955) :

Rogers, ,Ylf red P. : Exercises for the Development of the llluscles of the Face, With a Viclw to Increasing Their Functional Activity, Dental Cosmos 60: 857-876, 191N.

Rogers, Alfred P.: Increased Function in Treatment of Dental Anomalies, INT. .J. OWIIO- IKlNl'IA 15: 731-742, 1929.

Rogws, Alfrerl P. : The Place of Myofunctional Treatnwnt in the Correction of Itlalowlusion, CT. Am. Dent. A. 23: 66-78, 1Y:IR.

Rogers, Alfred P.: Evolution, I)evelopment, ant1 Application of Rlyofunctional Thrrap!~ in Orthodontics, Am. .T. Orthoilontics and Oral Surg. 23: 462-481, 1937.

,\lershon, .lohn V.: Facial Changes, Symposium, Dental (‘osmos 77: 1068-1079, 19%. hlrr~hon, .Tohn V.: Why the Lingual Arch Is Applicable to the Orthodontic I’rol~le~n, n.

Record 46: 297, 192fi. .\lershon, Sohn V.: The Removal-)le Lingual Arch Appliance, IiYT. J. ~RTHOlltlK’l’IA 12:

1002-1026, 1926. ,\Iershon, John V.: Failures, TKT. .J. OI<~aOI>OIGl’Iz\ 22: 338-343, 1936.