The Relationship Between Forward Head Posture andTemporomandibular Disorders

Won-You Lee, DDS, MSD. PhDAssistant ProfessorDepartment of OrthodonticsYonsei UniversityCollege of DentistrySeoul. Koreaand Orofaciai Pain ClinicWonjy College of MedicineWonju Christian HospitalWonju, Korea

Jeffrey P. Okeson, DMDProfessor and DirectorOrofacial Pain CenterUniversity of KentuckyCollege of DentistryLexington. Kentucky

Jofin Lindroth, DDSClinical ProfessorOrofacial Pain CenterUniversity of KentuckyCollege of DentistryLexington. Kentucky

Correspondence to:Dr Won You LeeOrofacial Pain ClinicDepartment of OrthodonticsWonju Christian hlospitalYonsei UniversityWonju College of MedicineWonju. Korea 220-701

This Study investigated the relationship between forward head pos-ture and temporomandibular disorder symptoms. Tbirty-three tem-poromandibular disorder patients with predominant complaints ofmasticatory muscle pain were compared witb an age- and gender-matched control group. Head position was measured from pho-tographs taken with a plumb line drawn from the ceiling to the lat-eral malleolus of tbe ankle and with a horizontal plane that wasperpendicular to the plumb line and that passed through thespinous process of tbe seventh cervical vertebra. The distances fromthe plumb line to the ear, to tbe seventh vertebra, and to the shoul-der were measured. Two angles were also measured: (1) ear-seventh cervical vertebra-horizontal plane and (2) eye-ear-seventhcervical vertebra. The only measurement that revealed a statisti-cally significant difference was angle ear-seventb cervical verte-bra-horizontal plane. This angle was smaller in the patients witbtemporomandibular disorders than in the control subjects. In otherwords, when evaluating the ear position with respect to the seventhcervical vertebra, the head was positioned more forward in thegroup with temporomandibular disorders than in the control group|T < .OS).

J OROFACIAL I'AIN 1995;9:161-lé7.

key words: temporomandibular disorders, head posture,masticatory muscle

In recetit years, the denta! profession has become increasinglyaware of the postural relationships between the head and neck.Many authors have suggested thar posture relates to the status

of health,'"'" and rhat poor posture can lead to pain and dysftinc-tion.'^'-'^' Several authors*''"" have suggested thar a forward headposrure is closely associated with certain tetnporomandibuiar disor-der (TMD) symptoms. With this assumption, some chnicians"""^have suggested that correction of the forward head posture is itidi-cated for the reduction of TMD symptoms. Unfortunately, the lit-erature does not contain many scientific studies that investigare therelationship between forward head posture and TMD .symptoms.In one study, Huggare and Raustia'"' found a relationship betweenforward head posture and TMD symptoms. In studies by Darlowet al"'" and Hackney et al,'' no such relationship was found. Itappears rhat a relationship between forward head posture andTMD symptoms has not yet been clearly established.

The purpose of this study was to determine if a group ofpatients with TMD symptoms presented with a greater incidenceof forward head posture than did a sex- and age-matched controlgroup.

Journal of Orofacial Pain 1 6 1

Lee et al

Fig 1 Subject positiotied between the rwo lateral plumblines- The dot on her shoulder marks the acrotnial jointof the shoulder, and the point marked on lier neck marksthe spinotis process of the seventh cervical vertebra.

Materials and Methods

Participants iti this sttuly were selected frotn agroup of patients who were referred to University'of Kentticky Orofactal Pain Center with TMDsymptoms. In order to be included, each subjecthad to meet the following criteria:

1, The subject's chief complaitit was related topaiti in the muscles of mastication.

2, Jaw movemetir and function increased thepainful condition,

3, The masticatory muscles (masseter and tempo-ralis) were tender to digital palpation,

4, The maximum comfortable interincisal openingwas less than 40 mm,

5, Temporomandibular joint (TMJ) pain may ormay not have been present,

6, Cervical muscle pain may or may not have beenpresent.

These criteria were developed to assure that masti-catory muscle pain was present. It was hypothe-sized that posture would likely have its greatestaffect on muscle function, and therefore, thepatient group should Include masticatory musclepain problems. Patients with masticatory mttsclepain who also had pain related to the TMJ or thecervical muscle were included. Patients who hadTMJ pain or cervical muscle pain but no mastica-tory muscle pain were excluded.

The patient group comprised 30 females andthree males with an average age of 31,4 years(± 10,1) and a range of 13 to 65 years. Thirty-three sex- and age-tnatched subjects were selectedas controls from a university student and staff

population who met the following sex and age cri-teria:

1. Each control subject reported no present orpast history of head or neck pain.

2, Digital palpation of the masseter and tempo-ralis muscles revealed no tenderness or paiti,

3. Comfortable mouth opening was greater than40 mm.

4, The age of each control subject was within ± 1year of the matched sub|ecc.

Each subject was asked to stand on a designatedspot on the floor. Three plumb lines were hungfrom the ceiling. One plumb line with a milhmeterruler was positioned in front of the subject's face,and the other two plumb lines were positioned tothe right and left of the subject's shoulders. Thesubject's feet were positioned so that the lateralplumb lines were 1 cm in front of the posterioredge of the lateral malleolus of the ankles. Thesubject was asked to stand in a comfortable posi-tion with the head held in its natural balatice andthe arms relaxed to the side. These instructionswere similar to the method described by WoodhuUet al," Each subject was instructed to focus on thehorizon through a window in front of which he orshe was standing. None of the subjects wasinformed that the study involved posture.

By manual palpation, the seventh cervical verte-bra (C7] was located and marked with tape. Theacromial joint of the left shoulder was also locatedas the most predominantly bony area of the supe-rior region of the shoulder. A 105-mm macroNikon camera was placed on a tripod and posi-tioned laterally 2 m from the subject's left side.

162 Vclutiieg, Number2, 1995

Lee et al

e reference linesthe eye; Ear = most

Fig 2 Subject from Fig 1 witlmarked. Fye - lateral corner ofsuperior portion of the e.\ternal svertical plumb line; C7 = spinous process of the sev-enth cervical vertebra; hp - horizontal plane throughC7, perpendicular to vp; SH = acromial joint of theshoulder.

The two lateral plumb lines were aligned to super-impose each other. The camera was raised until itwas at the level of the mandibular angle of thesubject, A color slide was then taken of each sub-ject ¡Fig 1),

The slide was developed and projected on gridpaper where measurements were taken. The dis-tances were measured by using the millimeter rulerin the photograph that had been positioned on theanterior plumb line. The following locations wereidentified on the grid paper:

1. Spinous process of C72. Most superior portion of the external auditory

meatus3. Acromial joint of the shoulder4. Lateral corner of the eye

A line perpendicular to the lateral plumb line wasdrawn to each of these locations, and the distancein millimeters was measured from the plumb lineto the landmark,

A horizontal plane reference (hp) was drawnthrough C7 perpendicular to the plumb line (Fig2). A line was drawn from C7 to the most superiorportion of the external auditory meatus (Ear), andanother line was drawn from Ear to rhe corner ofthe eye (Eye), The angle between hp and lineC7-Far was measured in degrees. The anglehetween C7-Ear and Ear-Eye was also measuredin degrees (Fig 2).

Results

Table 1 lists all raw dara collected from the con-trol subjects. Table 2 lists all data from the sub-jects with TMD symptoms. The mean values andstandard deviations for the five measurements aresummarized in Table 3. A paired í test was used todetermine whether any statistically significant dif-ferences existed between the TMD subjects and thecontroi subjects in any of the investigated measure-ments. The only one of five measurements thatrevealed a statistically significant difference wasthat of angle Far-C7-hp, This angle (Ear-C7-hp)was smaller in the TMD patients than in the con-trol subjects. In other words, when evaluating theear position with regard to C7, the head was posi-tioned more forward in the TMD group than inthe control group (P < .05),

Discussion

Several weaknesses must be acknowledged in thisstudy. The patients with TMD were not subdi-vided into specific diagnostic subcategories such asthose having only masticatory muscle pain orthose having only intracapsular pain disorders.Since this study did not evaluate specific subcate-gories, the conclusions can only be generalized tothe large group of patients baving masticatorymuscle pain with and without TMJ pain or cervi-cal pain. Another weakness of this study, as wellas any postural study, is that subjects may havealtered their normal head posture for the photo-

Joumal of Orofacial Pain 163

Lee et al

Table 1 Lengths and Angles Used For Determining Head Postureof Control Subjects

No,

12

34

567

e9

101115

131415161718192021232354555627282930313233

E a r .

v p .C 7 .

SH =Eye =h p .

Age

64

51434243413737363635353431313130292727

26252454545454532319171613

most supervertical pliirrspinous proacromial joii

•- laleral comhorizontal pi.

Gender

FFFFFMFFF

FMF

MFFFFFFFFFFFFFFFF

FFF

F

lor portion or ihib linecess of the sevnt of the shoulder of Ihe eyeane tfirough C7

ELI I-V p

( m 111 )

4,93.93.85 2

6 19.33.65.0

10.17.39 89.43.54 55 54 74 62.a7.55.24.98.06.93.95 1887 6

11 4

8 25 65.26.27.6

e e<temal audit

•enth cervical vee r

. perpendicular

Lengths

c:7-vp

(mm)

2.90.81.55 04.4

-0.63 62 7

-1.40.8

-0.6-2.0

5.4

5 53 32 54.02.41.62.81.30.41.7

2.92 4

0 0-0.4^ 2

-0.60.4

2.31,9

-0,6

ory mealiis

rrtebra

tovp

SH-vp(mm)

1.43.64 3

0 61.91.71 63 5

7 65.7

1 74.80 65 71 0

-0 62 9

3.64.22.62.4

7.87.21.01 0564 7

9 63.96.03.23.54.1

Angles

Eye-Ear-C7

(degrees]

14B126136147

135145149

143149144

145134151140

135135152140146149!41155140135145142142137

144140148145145

Ear-C7-hp(degrees)

5368634851505553

5250505851

5360565561485557

525350524956

605453555152

graph. In order to minimize any postural correc-tion, sub]ects were not mformed prior to the pho-tograph that this study involved posture.

The results of this study revealed no statisticallysignificant diffcretice hetween forwatd head pos-ture in a group wirh TMD and that in a sex- andage-matched control group in regard to four offive measuretnents. There was, however, a statisti-cally significant difference in angle Ear-C7-hp.Therefore, the results of this study are tnixed. Thefour tneasurements that revealed no statisticallysignificant difference are in agreetnent with the

findings of Darlow et al'"' and Hackney et al,'" buttiot in agreement with the findings of 1 luggare andRaustia." The only measuretnent that did reveal astatistically significant difference is in agreetnetitwith the findings of Huggare and Raustia," butnot in agreement with the findings of Darlow etaP' and Hackney et al."*"

It appears that rhe relationship between forwardhead posture and TMD is not a simple one.Additional well-controlled studies are needed toidentify the exact relationship, if any, between for-ward head posture and TMD sytnptoms.

164 Volume 9, Number 2, 1995

Lee et al

Table 2 Lengths and Angles Used For Determining Head Posture of SubjectsWith TMD

No.

1

234567

39

101112

1314

1516171819

2021222324

2526272829

30313233

Age

655042403939

363635353534343434

333231302928272726242424

232018161513

Gender

F

FFFFMFFF

MFMFFFFFFFFFFFFF

FFFFFFFF

Ear-vp

(mm)

3.95.2

5 57 34.27.29.67.2

10.018.2

4.710.1

5 08 84.96 76 08.67.35.24 04 59 27 a7.07.0

13.76.35 9

11 0

6 09 4

7.8

Lengths

C7-vp

(mm)

2.31.93.51.04.20.4

-0.7

1.5-2.9-7.6

3,40.4

3.00.04.20.4

1 1-1.4

1.31.93.43.1O.B

-3 20.90.6

-3.90 2

3 8-1 4

2 30 31 5

SH-vp

¡mm)

1 93.11.60.21.68.35.24.67.4

14.83.25.01.64.80 86.31 22.74.4

3.82.73 54 93 44 15.58.95.23.64.72.93.4

3.3

An g

Eye-Ear-C?

(degrees)

140152145144

14114114714714!

146134147

138151146142137147144136136144144144

139138138142156142128141143

;les

Ear-C7-hp

(degrees]

54

524849576053535549583B525350585853486152495145505540554547574348

exte ajdiloryEar = most superior portjovp=verticai plumb lireC7 = spinous process of the seventh cervical vertebraSH = acromral joint of the shoulderEye = lateral comer of the eyehp = hori2ontal plane through C7. perpendicular tovp

Table 3 Mean Values and Standard Deviationsof Measurements for Control Group and theGroup with the TMD

Measurement Control TMD

Ear-vp (mm)C7-vp (mm)SH-vp Imm)Eye-Ear-C7 (degrees)Ear-C7-hp (degrees)

6 2

1.63.6

142.5

54.1

±2.3

±2.2± 2 4± 6 1

±4.5

7.4 ±3.0

142.5 ±5.5

• P i 05Ear = moEl superior portion of the eïtemal auditory mealusvp = vertical piumb iineC7 = spinoiis process o( the severlh cervicsl vertebraSH ^ acromiai lOint of the shouiderEye = laterai comer of liie eyehp = horizontal piane through C7, perpendiouiar to vp

Journal of Orofacial Pain 165

Lee et al

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Haten WP, Lucio RM, Russell JL. Assessment of totalhead excursion and testing head posture. Arch Phys MedRehabil 1991;72;877-880.McLean LF, Brenman HS, Friedmand MGF. Effects ofchanging body position and dental occlusion. J Dent Res1973;52:1O4I-IO45.Fiinakoshi R, Fujita N, Takehana S. Relations betweenocciusal interference and jaw muscle activities in responseto changes in bead posture. J Dent Res 1976;55:684-690.Makofsky HW, SeMon TR, Diamond DZ, Sexton MT.The effect of bead posture on muscle contact positionusing the T-Scan system of occlusal analysis. JCraniomand Pract 199 1;9Í3 16-321.Heilsing E, Forsberg CM, Linder-Aronson S, et al.Changes in postural EMG activity in neck and masticatorymuscles following obstruction of the nasal airways. EurJOrtbod 1986;8:247-253.Hellsmg E, McWilliani J, Reiugo T, et al. Tbc relationshipbetween cranioíacial morphology head posture and spinalcurvature in 8, I I , 15 year old children. Eur J Orthod1987:9:254-264.Robinson MJ. The influence of head posrute on the TMJdysfunction. J Prosthet Dent 1966,16:169-172.Kraus SL. Physical therapy management of TMJ dysfunc-tion. In: Kraus SL (ed). TMJ Disorders, Management ofCraniomandihular Complex. New York: ChurchillLivingstone, 1988:139.Huggare A. Association between morphology of tbe firstcervical vertebra, bead posture, craniofacial structures.Eur J Ortbod 199I;13:435-t4O.Huggare J, Pitttinieimi P, Serlo W. Head posture anddentofaciai morphology in subjects treated for scoliosis.Proc Finn Dent Soc 19S1;87:151-158-Huggare J. Population differences in the morphology ofthe first cervical vertebra. Am J Pbys Anthropol 1992;8a:197-201.Huggare JA, Raustia AM. Head posture and cervicovcrtebraland craniofacial morphology in patients with cranioman-dibuiar dysfunction. J Craniomand Ptact 1992;10:173-179.Dunn J. Physical therapy. In: Kaplan AS, Assael LA (edsj.Temporomandibular Disorders Diagnosis and Treatment.Philadelphia: Saunders, 1992.Darling DW, Kraus PT, Glasheen-Wray MB. Relationshipof head posture and the rest position of the mandible. JProsthet Dent 1984:52:111-115.Morgan DH, House LR, Hall WP, et al. Disease of theTemporomandibular Apparatus, ed 2. St Louis: Mosby,1982.Mohl NO. The temporomandibular joint. In: Mohl ND,Zarb GA, Carlsson GE, Rugh JD (eds). A Textbook ofOcclusion. Chicago: Quintessence, 19g8:S¡-Se.Janda V. Muscles and cervicogenic pain syndromes. In:Grant R (ed). Physical Therapy of tbe Cervical andThoracic Spine. New York: Chnrchill Livingstone,1988:153-166.Enwemeka CS. Bonet IM, Ingle JA, et al. Postural correc-tion in persons with neck pain, 1. A survey of neck painsrecommended by physical tberapists. J Orrhop Sports PhysTber 1986;8:235-239.Enwemeka CS, Bonet IM, Ingle JA, et al. Postural correc-tion in persons with neck pain, II. Integrated clecttomyo-graphy of the upper trapezius in tbree simulated neckpositions. J Orthop Sports Phys Tber 1986i8:240-246.Shiau YY, Ghai HM. Body posture and hand strength ofpatients with temporomandibular disorder. J CraniomandPtaa 1990; 8:244-251.

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Resumeti

La Relacrón entre la Postura Anterior de la Cabeza y losdesórdenes Temporomandibuiares

Este estudio investigó la relación entre la posición anterior de lacabeza y los síntomas de desórdenes temporomandibuiares(DTW). Se compararon 33 pacientes que sufrían de DTW conproblemas predominantos de dolor muscular masticatorio(grupo experimental), con un grupo de control cuyas edades ygéneros eran iguales a las del grupo expenmental. Se midió íaposición de la cabeza en las fotografias tomadas con una plo-mada que caia desde ei techo hasta ei maiéolo iateral deltobillo, y con un piano horizontal que estaba perpendicular a laplomada y que pasaba a través del proceso espinoso de la sép-lima vértebra cervicai. Se midieron las distancias de (a piornadaai oído, a ia séptima vértebra, y ai hombro. También se midierondos ángulos formados por: fíJ la ore|a-séptima vertebra cervi-cal-plano honzontai y (2) ei o]o-ore¡a-séptima vértebra cervical.La única medida que indicó ia existencia de una diferenciaestadisticamente significativa, fue ia del ángulo fue maspequeño en ios pacientes con DTM en comparación al grupo decontroi. En otras paiabras, cuando se evaiuó la posición de laoreja con respecto a la séptima vértebra cervical, ia cabeza seposicionó mas anteriormente en ei grupo que sufría de DTM encomparación ai grupo de control tP-i 0,05),

Zusammenfassung

Die Beziehung zwischen Vorhaltesteliung des Kopfesund Myoarlhropathien des Kausytems (MAP)

Diese Studie untersucbte den Zusammeniiang zwischen derVorhaitesteilung des Kopfes und Symptomen derMyoarthorpathie des Kausystemes (MAP), 33 Patienten mitMAP. mit Sciimerzen hauptsachlich m der Kaumuskulatur, wur-den mil einer Kontroilgruppe gieicher Aiters- und Ge.schlechtsverteiiung vergiichen Die Kopfposition wurde aufPhotos gemessen, die mit einer senkrechten Linie won derDecke zum Malieolus des Knöcheis und einer dazu rechtwinkligverlaufenden hiorizontaien durch den processus spinosus dessiebten Haiswirbels aufgenommen worden waren Der Abstandzwischen der Senkrechten und dem Ohr, dem processusspinosus und der Schuiter wurde gemessen. Des weitern wur-den 2 Winkei gemessen- I. Ohr-siebter Haiswirbei-Honzontale.2 Auge-Ohr-siebter Haiswirbel. Der einzige Wert, der statis-tisch signifikante Unterschiede aufzuweisen vermochte, war derWinkel Ohr-siebter Halswirbei-Horizontale. Dieser Winkel warbein MAP-Patienten kieiner ais m der Kontroiigruppe, Mitandern Worten, wenn die Position des Ohrs reiativ zum siebteniHalswinkel vergiichen wurde, trugen die MAP-Patienten ihrenKopf mehr nach vorne gehaiten ais die Probanden derKon troll gruppe (P< 0,05).

Journal of Orofacial Pain 167