03-biomechanical foot function i

8/2/2019 03-Biomechanical Foot Function I

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B l o m e c h a m c a l f o o t fu n c U o n :a p o d ia t r ic p e r s p e c t i v e : p a r t 10 0 0 0 0 0 0 0 0

T. D . P r i or

T r e v o r D . P r io r B S c H ons F P odA M C hSC o n s u l t a n t Po d ia t r i s t, D e p a r tme n t o f Fo o t H e a l th ,S t Le o n a rd ' s P r ima ry C a re C e n t re , N u t t a l l S t r e et ,L o n d o n N 1 5 L Z , U K

Correspondence to: -i2 D. P rio rR e c e iv e d Se p te mb e r 1 9 9 8A c c e p t e d J a n u a r y I 9 9 9

Journal of Bodywork & Movement Therapies(1999)3(2), 74-84 Harcourt Brace & Co. Ltd 1999

I n t r o d u c t i o nB ipeda l up r igh t locomot ion i s one o fthe de fining charac ter is tics of thehum an race , ye t i t is s o o f t e n t a ke n fo rgranted. The fee t a re essent ia l ly thefounda t ion fo r the res t o f the bod y a ndare l i te ra l ly pivota l in a l low ing us towalk eff iciently . Unders tan ding norm alfunc t ion i s a f imda m en ta l pa r t o fa s s e ss ing dys fu nc t ion a nd e f fec t ive lytrea t ing pa t ients . However, anunde rs t and ing o f the ba s i c unde r ly ingstructure is essential. This paperin tends to de s c r ibe s ome o f the cu r re n tconcepts re la t ing to foot funct ion froma podia tr ic perspect ive . Havingdeveloped these concepts , Part 2 wil lde s c r ibe ho w abnorma l i ti e s ma y re s u l tin dy s func t ion and pa tho logy . Ana t t empt ha s bee n m ade to p rov ide t e st stha t enable the reader to ga in a bas icunde rs t a nd ing o f foo t func t ion . Someof these tes ts have a c l in ica l va luewhen assess ing pa t ients . Part 2 ( to bepubl ished in a future is sue) wil lde s c r ibe in m ore de p th thecons equenc es o f abnorm a l f ind ings .

A n a t o m i c a l s t r u c tu r ea n d f u n c t i o nIn the 1950s H ic ks p roduced twopapers tha t described bas ic osseous

a nd s o f t ti s sue func t ion o f the foo t(Hicks 1953, 1954). In th e first paper,he conce n t ra t e d on the os s e ouss truc tures of the foot , pr imari ly thesubta lar jo in t (STJ) , m id-tarsa l jo in t(M TJ ) a n d the me ta ta r s opha la nge aljo ints (MTPJs)(see Fig . 5) .

H ic ks (1953) de mons t ra t e d by theus e o f rods and po in te r s tha t j o in t srota ted around axes ra ther l ike thehinge o f a door and tha t , because theseaxes are angula ted agains t the pr imarybody p lanes , mo t ion w i l l oc c u r in morethan one p la ne.

The STJ e xh ib i t s N-p la ne r mo t ionwhere pronat ion is represented byevers ion, abduct ion and dors i f lexionwhils t supina t ion is represented byinvers ion, adduct ion and plantarf lexion(See Test 1).

The M T J ac tua l ly consi s ts o f theta lo-navicular jo in t (TNJ) a nd theca lcaneo-cu boid jo in t (CCJ); thec ombine d m ot ion o f the s e two jo in t sa l lows t r i -p laner motion (Test 1). Inaddi t ion to the STJ a nd MT J, the 1 tand 5th meta tarsa ls a lso have the ir ow na xes o f mo t ion , p r ima r i ly do rs i f l e x ionand plan tar t texion (Tes t 1) .

Thes e mot ions o f the STJ , M T J andmeta tarsa ls a re a l l essent ia l to a l lownorma l foo t func t ion and a reinter l inked. I f the foo t were a r ig ids t ruc tu re then p rona t ion o f the STJ

JOURNA L OF B ODY WORK A ND MOV E ME NT T HE RA P IE S A P R I L 1 9 9 9


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Biomechanical foot function

( a ): :S o t h a t i t ro t a te s t h e l e g : : :t in g f Y o u S h o u ld a i m t o : : : : : ia f f i C i ~ n t l y : o t h a t : t h e : : :::= :L s ~ l e l W i th : t h e : It o o ~ ( b ) :

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J O U R N A L O F B O D Y W O R K A N D M O V E M E N T T H E R A P I E S A P R I L 1 9 9 9


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Prior

It

Supinat ion =invers ion,a d d u c t i o n ,

c p lantar f lex ion

Pronat ion =evers ion,a b d u c t i o n ,

dors i f lex ion

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(evident by eversion of the calcaneus)would cause the lateral border of theforefoot to lift off the ground.Similarly, supination (evident bycalcaneal inversion) would result in themedial aspe ct of the forefoot lifting offthe ground. This clearly does nothappen during walking and this isbecause of the compensatorymechanisms that can occur in the mid-tarsal and forefoot. Namely, pronationresults in MTJ inversion, 1st metatarsal(lst ray) dorsiftexion and 5thmetatarsal plantarflexion. The oppositeis true with supination (Test 2). Thus,the foot is able to adapt to varyingpositions enabling locomotion overuneven surfaces whilst maintainingbalance. Hicks postulated that rigidityin the midtarsal area would result in aloss of balance.In his se cond paper, Hicks (1954)described the role of the plantaraponeurosis (fascia) in stabilization ofthe foot. The fascia originates from theplantar aspect of the calcaneus andinserts via the plantar pad and theflexor apparatus into the base of theproximal phalanges o f the digits. As aresult, he likened the fascia to awindlass mechanism with the fascia

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I

JOURNAL OF BODYWORK AND MOVEMENT THERAPIE S A P R I L 1 9 9 9

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the cable, the metatarsal heads thedrum and the toes the arms. Thus,dorsiflexion of the digits results in at ightening o f the windlass m echanismwhich in turn results in plantarflexionof the m etatarsals. As this effect isgreatest at the 1st metatarsal, there willbe a relative inversion of the foo t, thusthe arch will rise and the leg, via theSTJ, w ill externally rotate. Thisfunction actually occurs in the latterpart of stance as the foot dorsiflexesover the stable toe and will helpprovide intrinsic stability to the foot(Test 3).

In 1979, Bojsen-Moller describedhow the metatarsal axes would effectfoot function. He described two axes,namely the obl ique or low gear axisrepresented by the 2nd-5th MTPJs ,and the transverse or high gear axisrepresented by the 1s t and 2nd MTPJs(Fig. 1). He observed two basic typesof toe-off , namely low and high gear.When a subject demonstrated toe-offthroug h the high g ear axis (i .e. 1st and2nd MTPJs) he observed that theplantarfascia and peron eal tendonswere tight and that the 1s t MTPJ was

dorsiflexed. This suggests that thewindlass m echanism described byHicks (1954) is active. As a result, the1st ray will be plantarflexed andstabilized against the ground byperoneus longus. In addition, thetens ion in the peroneus longus tendonwill cause a rotation at the cuboid (asthis is its fulcrum point) thus furtherstabilizing the mid-tarsal area. Incontrast the soft tissue structures werenot taut with a low ge ar toe -of f (i.e.through the 2nd-5th MTJPs) and thehallux was plantarflexed to helpstabilize the medial aspect of theforefoot. Thus, the stabilizing effect ofthe windlass mechanism and theperoneus longus are lost.

Podiat r ic conceptsIn 1977 Root et al described theirconcept of normal and abnormal footfunction. This primarily revolvedaround the posi t ion and f imct ion of theSTJ, MTJ and 1st ray. They desc ribed aneutral foot position such that the footis in its neutral position when thesubtalar joint is in neutral (neither

High gear(transverseaxis) Low gear(obliqueaxis)

Fig. 1 The high gear (metatarsals i-2) andlow gear (metatarsals 2-5) axes asdescribed by Bojsen-Moller (1979).

supinated nor pronated) and themidtarsal joint is maximally pronated.They further proposed that the

posterior bisect ion of the calcaneus andthe lower one-third of the leg would b eparallel and at a right angle to theweight bearing surface and that theplane o f the metatarsals (fore foot)would b e paral le l with the weightbearing surface when the foot is in thisneutral position (Fig. 2).

In order to assess these osseousalignments there are several methodsof placing the f oot into its neutralposition. The first stage is to place theSTJ into neutral. Root et al (1997)

Fig. 2 "Theneutral position described byRoot et al (1977) whereby the posteriorbisection of the lower one-third of the legand calcaneus are parallel and at a rightangle to the supporting surface. The planeof the metatarsals is parallel with thesupporting surface.

J O U R N A L O F B O D Y W O R K A N D M O V E M E N T T H E R A P I E S APR I L 1 9 9 9


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Pr ior

postu lated that two- th i rds o f the rangeo f S TJ mo t io n wo u ld b e i n su p in a t i o n(as ind icated by calcaneal invers ion)wi th o n e- th i rd i n p ro n a t i o n ( asind icated by calcaneal evers ion) . Thus,b y measu r in g t h e t o t a l r an g e o f mo t io nan d p e r fo rm in g a s imp le ca l cu l a t io n ,the relat ionsh ip o f the heel to the leg inS TJ n eu t r a l can b e o b t a in ed . Ho wev er ,so me r esea rch h as i n d i ca t ed t h a t,whi ls t the average STJ neu t raldemonst rates a one- th i rd to two- th i rdsrat io , there i s considerab le var iat ionamo n g s t n o rm al su b j ec t s (Ba i l ey e t al1984) . Fur thermore, the repeatab i l i tyo f t h ese measu remen t t ech n iq u es ,p a r t i cu la r l y b e tween ex amin er s ( i nt e r -t e s te r ) , i s ex t r emely p o o r an d t h e re fo request ions the val id i ty (Weiner Ogi lv ieet al 1997).

An a l t e rn a t iv e t ech n iq u e o f p l ac in gthe STJ in to neu t ral i s v ia palpat ion oft h e h ead o f t h e t a l u s. Th e p rac t i t i o n erp l aces t h e t h u mb an d fo re f i n g er o n t h emed ia l an d l a te r a l a sp ec t o f th e h ead o fthe ta lus . The STJ i s then takenth ro u g h i t s r an g e o f mo t io n w i th t h emed ia l a sp ec t o f th e h ead o f t h e t a l usp ro min en t wi th S TJ p ro n a t i o n , wh i l s tthe la teral aspect o f the head i sp ro min en t o n S TJ su p in a t i o n . Neu t r a l

i s ach i ev ed wh en n e i t h e r a sp ec t o f t h eh ead i s p ro min en t . T h i s t ech n iq u ec l ea r l y cau ses p ro b l ems w h en t h e re a r evar iat ions in anato my or an y sof t ti ssueswel l ings p resen t .

I t has been th is au thor 's c l in icalo b se rv a t i o n th a t , wh en t h e fo o t i sp l aced i n to t h e f ro n t a l p l an e an dal lowed to hang wi th g rav i ty , therelat ionsh ip o f the calcane us to the legi s ex t r emely c lo se t o t h e p a lp a t ed o rcalcu lated STJ neu t ral posi t ion . Thiswo u ld t h e re fo re ap p ear t o b e a s imp le rway fo r man y p rac t it i o n ers t o p e r fo rmth e as ses smen t . I n d eed , t h e re wo u ld b esom e log ic in th is assumpt ion as al l theosseous and sof t t i ssue s t ructuresa ro u n d t h e S TJ wo u ld b e i nequi l ib r ium at th is po in t and thus inth e i r o wn fo rm o f n eu t r a l p o s it i o n .

On ce S TJ n eu t r a l h as b eenach i ev ed, p r es su re b en ea th t h e 4 th an d5 th meta t a r sa l h ead s t o max imal lyp ro n a t e t h e M T J i s r eq u i r ed t o p lacethe whole foo t in to neu t ral . However ,th is p ressure should on ly be suff ic ien tt o p ro n a t e th e M TJ an d n o t t h e S TJ. I fan y ev er s io n o f t h e ca l can eu s i so b se rv ed o n ce S TJ n eu t r a l h as b eenach i ev ed , t o o mu ch p res su re h as b eenappl ied to the fo refoo t (Test 5 ) .

On ce t h e fo o t h as b een p l aced i n toneut ral , the relat ionsh ip of the heel toth e l eg (S TJ p o s i t i o n ) and t h e p l an e o ft h e fo re fo o t to t h e r ea r fo o t ( a sd e t e rmin ed b y a p e rp en d i cu l a r t o t h eb i sec t i o n o f t h e p o s t e r i o r a sp ec t o f t h eca l can eu s ) can b e as ses sed as e i t h e rinver ted , paral le l o r evened .

The pos i t ion of the 1st and 5 th rayscan b e as ses sed b y ex amin in g t h eamo u n t o f d o r s i f lex io n andplan tarf lex ion of the metatarsals inrelat ion to the cen t ral th ree metatarsals .Th e meta t a r sa l b e in g ex amin ed i sp l aced i n t h e same p l an e as t h e cen t r a lmetatarsals as a basel ine. A greaterd eg ree o f d o r s i f lex io n t h anplan tarf lex ion ind icates a dors i f lexedray whi ls t the converse represen ts ap lan tarf lexed ray (Te st 1 ) .

Th e r ea r fo o t p o s it i o n sh o u ld b eex amin ed fu r t h e r wi th t h e p a t i en ts tand ing . The pat ien t i s asked to take afew s teps on the spo t and then s topwi thout re-ad just ing the foo t posi t ion .Th i s en ab l es t h em to s t an d i n th e an g l eand base o f s tance, i .e . the feet have as imi lar posi t ion towards one ano theran d t h e d i r ec t i o n o f p ro g ress io n as t h eywould do dur ing walk ing (F ig . 3 ) . Inth is res t ing posi t ion , the ang le the heelmak es t o t h e g ro u n d i n d ica t es t h ed eg ree o f co mp en sa t i o n o ccu r r i n g an di s k n o wn as t h e r e l ax ed ca l can ea ls t an ce p o s i ti o n (RCS P ) . By p l ac in g t h eSTJ in to neu t ral , the overal l neu t ralca l can ea l s t ance p o s i t i o n (NCS P ) canbe assessed . This posi t ion has thead d ed ad v an t ag e o f i n t ro d u c in g th et ib ial ang le to the overal l rearfoo tp o s i t i o n . By co mp ar in g t h e NCS P toth e RCS P o n e h as an i n d i ca t i o n o f t h ed eg ree o f mo t io n t h a t i s o ccu r r i n g (Tes t6) . In the 1980s, K irby descr ibed theposi t ion o f the S TJ ax is in relat ion toth e t r an sv er se p l an e o f t h e fo o t (Ki rb y1987 , 1989) . He descr ibed a method ofpalpat ing the p lan tar aspect o f the foo tt o d e t e rmin e t h e p o s i t i o n o f t h e ax i s(Test 7 ) . The STJ ax is on the p lan tarasp ec t o f t h e fo o t r ep resen t s t h e p o in to f eq u i l i br i u m. Th u s , an y p res su reap p l i ed t o t h e so l e o f t h e fo o t med i a l t oth is ax is wi l l cause sup inat ion whi ls t



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Biome chanical foot function

Aiis; observe the heei t6 leg: reiafio~shi~;ensure that the STJ does no tpro nat etemons trated by calcaneal eversion),~bserve the an gle o f the hee l to:the legi:[so observe the a ngle that the plane O fle forefoot makes in relationship to a::erpendicular bisection of the posterior

;~0rsiflexion force o n :the foot,. . . . . . . . . You:~11~0 te :~ at the toes::dorsiflexand the : : :;C~i~us :'evertS: past ::neutral Th iS: : :::foot~ d it is:n0 onger : ~when increased force::iS:lateral forefoot ~ d the~ail, pronated ~ it ~

trjo~t ab~a ii ~will be: paralleii: f: ,ia or everted oetion may od ~: 6n :

pendicui~:t0 '~ e p~sterior: :~cti6h Of he ,:heel ~ d :the p!~metatarsa!headsi ilAgain~a pa

may:result in:,,

B

0Forefoot to rea rfoot angle: : : : . . . . . . . . . =

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pressure lateral to this axis will causepronation. By determining the positionof this axis on the plantar aspect of thefoot, the practitioner is able to gaugethe relative amounts o f pronation andsupination moments being placedacross the STJ axis.In 1986 and 1993, Dananbergdescribed a sagittal plane mo del o f footand leg function. The basis o f hisconcept was the pivotal nature o f theweight bearing foot that has beendescribed by Perry (1992). Essentially,the foot is a pivot over which the bod yis able to progress forward. Perrydescribed a rocker system wherebythere is weight transfer from the heel

rocker to the ankle rocker and finallythe for efoot rocker (Fig. 4). In orde r forthis system to function effectively heremust be ankle joint plantarflexion andassociated knee and hip flexionfollowing heel strike to foot flat (heelrocker). The ank le join t thendorsiflexes whilst the knee and hipextend during the ankle rocker phase.Thus, as the leg prepares for theforefoot rocker, the knee and hip arerelatively extended to providemechanical advantage for the hipflexors to accelerate the leg into swing.As the foot goes into the forefootrocker phase, the MTPJs dorsittex, theankle joint plantarflexes and the knee

Line of progression

"~ Ba seof gaitAngle of gait /A 'i

Fig. 3 The an gle the foot makes in relationto the line or direction of progression (angleof gait) and the distance between the twofeet (base of gait).



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Prior

tL0

(NCSP = STJ

:thek h e ~ e w m ] l d

a o r m a t l y . : : :

"Tibialangle|

s i#a /

/~# NCSP,,

)os i t ion +t ib ia l posi t ion

and hip flex. The swing limb is thenaccelerated forward by the hip flexorsuntil the weight of the limb passesbody mass a t which t ime mom entumand gravity pull the body forward.This permits an efficient mod e o ffunction.

In order for this motion to beefficient, adequate 1st MTPJ and anklejoint dorsiflexion, normal knee and hipfunction, and equal leg lengths arerequired for a sm ooth transfer of therocker system.

they will not allow normal function,whilst if they are weak they will beunable to control function. Withparticular reference to the foot, c alfmuscle inflexibility and tibialisposterior muscle fun ction areimportant. Inflexibility of the calf

muscle will limit ankle jointdorsiflexion whilst w eakness o f tibialisposterior will reduce the control itexerts on STJ pronation.

Root et al (1977) postulated thatwhen the foot was placed in neutralthere was adequate c alf muscle

Muscle funct ionStrength and flexibility of theassociated musculature is extremelyimportant. Contrary to pop ular belief,the majority of muscles functioneccentrically, rather thanconcentrically, during walking.Therefore, their strength and flexibilityin controlling motion is extremelyimportant. If muscles are inflexible

A Hee l Rocker B Ankle Rocker C Meta tarsal RockerFig. 4 The heel (A), ankle (B) and forefoot (C) rockers which allow weight transfer duringthe support phas e of gait (Pe rry 1992).

JOURNAL OF BODYWORK AND MOVEMENT THERAPIES APRIL 1999


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A

" :i : i i- ; : " : : " " : :: " ~

tD

,iittm: :mov e ~r0ximal one more tirri@itree points 0 f equilibrium that Can ~J:axis in relation to:the transverse p~~ween he t sta nd 2nd metatarsal ~

o n t h e f o o t : Deviatii

ill i i i i

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flexibility if the foot could bedorsiflexed to 10 past the right a ngle(Test 8).

While testing of the functionalstrength of the muscles acting aroundthe ankle it is important the mechanicaladvantage o f the tibialis posterior

muscle and tendon should also beassessed (Test 9). It is not un com monin patients who dem onstrate severepronation for the tibialis posteriortendon to become lengthened(attenuated). In these instances,mechanical advantage is lost. Because

the tendo A chilles insertion is locatedclose to the STJ axis this is unable toinitiate inversion o f the heel. However,the tibialis posterior tendon is the m ostmedial tendon in the ankle and this isable to aid inversion. As the heelinverts, the tendo Achilles insertion

J O U R N A L O F B O D Y W O R K A N D M O V E M E N T T H E R A P I E S APRIL1999


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P r i o r

Place the f oo t in to :6eut ra idescribed ( Te a :~)! N0w: dorsiflex ~e fo~i whilsi pi

;: A:: (:: 1 0

, l o ,

: i~ or : prohat i0n a t the subta lar?il l : i :i . . . .toW:~, 'se~sment of the :presence of

t equinus. : There are n of lue s; bu t t h is ang i e be co m e s~h ~ i t exceed s : the he ei Canti : i ( t h g l e :~ caused by the: :h i th e s h oe) ; Th is W ini b ir tt d o r s i f l e x i o n a n d~ ~f~ect o gast~o~nemi~

Row ~ e~ df i a l : a s se s sm en t o f oiS muscle::flexib~ity.A: further 2 0.~xi~ilityshould::be available,m s a t io n s : a n t o6cn~mius inflexibili ty bu t tendsi'more reievant::du ring nm ning l

i oc

b e c o m e s r e l a ti v e ly m e d i a l t o t h e S T Jax i s and t he r e f o r e con t i nues t heinve r s ion m o t ion .

N o r m a l g a i tAs p r ev ious l y de sc r i bed , t he s ag i t t a lp l a n e r e q u i r e m e n t s f o r n o r m a l f u n c t i o na s d e s c r i b e d b y P e r r y a n d D a n a n b e r g .Roo t e t a l . a l so de sc r i be no r m a l f oo tf unc t i on p r im ar i l y r e l a t i ng t o t hef r o n ta l p l a n e . T h e y d i v i d e d t h e w a l k i n gcyc l e i n to t he s t ance ( we igh t bea r i ng )p h a s e a n d s w i n g ( n o n w e i g h t b e a r i n g )phase . The s t ance phase was f u r t he rdivided in to heel s t r ike , foot f la t , mid-s t ance , hee l l i f t and t oe - o f f . Theyd e s c r i b e h o w t h e h e e l w o u l d c o n t a c t

t he g r ound s l i gh t l y i nve r t ed bu t , due t og r ound r eac t i on f o r ce s , t he sub t a l a rj o in t wou l d p r ona t e a t f oo t f l a t . Theyb e l i e v e d t h is p r o n a t i o n a i d e d s h o c ka b s o r p t io n . H o w e v e r , b e c a u s e t h e o t h e rl eg i s i n the sw ing phase , an d t he r e f o r ebe i ng acce l e r a t ed f o r war d a t t h i s s t age ,t he r e m us t be an ex t e r na l r o t a t i onb e i n g p l a c e d o n t h e w e i g h t b e a r i n g l e g .Th i s ex t e r na l r o t a t i on o f t he we igh tbea r i ng l eg wi l l r e su l t i n sup ina t i on o ft he we igh t bea r i ng f oo t . Thus , t hesup ina t i on o f t he ST J ( a s a r e su l t o f t heex t e r na l r o t a t i on o f t he l eg ) w i l l c auset h e f o o t t o g o f r o m a p r o n a t e d p o s i t i o nth r ough neu t r a l t o a sup ina t ed pos i t i on .T h e y p o s t u l a t e d t h a t t h e n e u t r a lp o s i t i o n w o u l d o c c u r i n t h e m i d d l e o f

m id - s t ance ( i . e . t he po in t a t wh ich t hem a l l eo l i a r e l eve l ) . P r ona t i on wasthough t t o be r equ i r ed a t f oo t f l a t t oa l l o w t h e f o o t to b e c o m e m o b i l e s o t h a ti t cou ld adap t t o va r y ing t e r ra in , w h i l s ts u p i n a ti o n a t t o e - o f f w a s r e q u i re d f o rt he f oo t t o be a r i g id l eve r f o rp r opu l s i on .H o w e v e r , m o r e r e c e n t re s e a r c h h a sind i ca t ed t ha t t he STJ r em a insp r ona t ed wh i l e t he hee l i s i n con t ac tw i t h t h e g r o u n d ( M c P o i l & C o r n w a l l1994 , P i e r r ynowsk i & Sm i th 1996 ) . I twou ld t he r e f o r e appea r t ha t t heex t e r na l r o t a t i on o f t he we igh t bea r i ngl im b i s no t su f f i c i en t t o ove r com e t hep r o n a t i o n m o m e n t p r o v i d e d b y g r o u n dr eac t i on f o r ce s .



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1st ray

1ST METATARS{phal angea ljoint (MTPJ)

Sesamoid1st metatarsal

1st cuneiform

tatarso-I joints (MTPJ)

etatarsal/ray3rd cuneiform

Navicular clTalo-navicular ~eo-cuboidjoin t (TNJ) CCJ)

Talus

Talo-navicular +calcaneo-cuboid joi= Midtarsal joint (IVleus

Combining the literature covered inthis paper it would suggest that thefol lowing broad con cepts arenecessary for normal funct ion:

i t Talus . . . .

X 2 ~ l ~ ' ~ ! ! i r c u a l ~ t~n e o m 1st ray~ . ~J , 1st metatarsal }

Calcaneus Subtalar Calcaneo-cuboid Sesamoid bonejoint (STJ) joint (CCJ)

Fig. 5 A diagram of the fo ot in a dorso-plantar (a) and lateral view to describe the anatomicallandmarks.

1. Forward progression is caused byaccelerat ion of the non-weightbearing l imb and the momentumof body mass .

2. At heel strike, the heel rocker isactive and the heel is relativelyinverted in the frontal plane.

3. At foot fiat, the body passes intothe ankle rocker phase and theSTJ is pronated by ground reac-tion forces.

4. As the bod y progresses throughthe ankle rocker phase pronat ionis maintained bu t the knee and hipextend while the ankle jointdorsiflexes.

5. As the body passes into themetatarsal rocker the MTPJsdorsiflex, the ankle jointplantarflexes and the hip and k neebegin to flex as the hip flexorsstart to accelerate the leg.

JOURNAL OF BODYWORK AND MOVEMENT THERAPIES APRIL 1999


11/11

Prior

The MTJP do r s i f l ex ion in i t i a t e s thewind la s s mechan i sm and th i s ,combined wi th the h igh gea r toe o f f ,faci l i ta tes a s table base for toe off .Th e s e c o n c e p t s e n a b l e a b a s i s f o r

eva lua t ing func t ion (Tes t 10 ) .

Con c l u s i o nTh e r e i s m u c h l i t e r a t u r e r e l a t i n g t on o r m a l a n d a b n o r m a l f o o t f u n c t i o n a n dg a it . B y r e v i e w i n g s o m e o f th el i t e r a t u r e a v a i l a b l e , a n d d e t e r m i n i n gfa i r ly s imp le c l in ica l t e s t s , i t enab le st h e c l i n i c i a n t o f o r m a b a s i s a b o u twh ich to a s se s s and t r ea t pa t i en t s . I t i sc l e a r th a t m o r e r e s e a r c h i s n e e d e d f o ru s t o fu l l y u n d e r s t a n d n o r m a l f o o tf u n c t i o n. I n th e s e c o n d p a p e r t h e s ec o n c e p t s w i l l b e r e v i e w e d a n d r e l a t e dt o a b n o r m a l f u n c t i o n. M e t h o d s o ft r e a t m e n t a n d f u r t h e r a r e a s o fi n v e s t i g a t i o n w i l l b e c o v e r e d .

REFERENCESBailey DS, Perillo JT, Forman M 1984 Sub-talar

joint neutral, a study using tomography.JAPMA, 4(2): 59-64

Bojsen-Moller F 1979 Calcaneocuboid joint andstability o f the longitudinal arch o f the rearfootat high and low gear push off. Journal ofAnatomy, 1:165-176

Dananberg HJ 1986 Functional hallux limitusand its relationship to gait efficiency. JAPMA76(11): 648-652Dananberg HJ 1993a Gait style as an etiology tochronic postural pain, Part I. Functional halluxlimitus. JAPMA 83(8): 433-441

Dananberg HJ 1993b Gait style as an etiology tochronic postural pain, Part II. Posturalcompensatory process. JAPMA 83(11): 615-624Hicks JH 1953 The mechanics of the foot, Part I.The joints. Journal of Anatomy 87:3450-357

Hicks JH 1954 The mechanics of the foot, PartII. The plantar aponeurosis and the arch.Journal of Anatomy 88:2 5-31Kirby KA 1987 Methods for determination ofpositional variations in the subtalar joint axis.JAPMA 77(5): 228-234

Kirby K A 1989 Rotational equilibrium across thesubtalar joint axis. JAPMA 79(1): 1-14

McPoil T Cornwall MW 1994 Relationshipbetween subtalar joint neutral position andpattern of rearfoot motion during walking.Foot & Ankle 15(3): 141-145

Perry J 1992 Basic functions. In: Perry J (ed).Gait Analysis: Normal and PathologicalFunction Slack, Thorofare NJ31Pierrynowski MR Smith SB 1996 Rearfootinversion/eversion during gait relative to thesubtalar joint neutral position. Foot & Ankle17(7): 406-412Root ML Orien WP Weed JH 1977 ClinicalBiomechanics: Normal and AbnormalFunction of the foot, Vol 2. ClinicalBiomechanics Corp Los Angeles

Weiner Ogilvie S Rendall GC Abboud RJ 1997Reliability of open kinetic chain subtalar jointmeasurement. The Foot 7(3): 128-134

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03-biomechanical foot function i

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