2006 july anatomy

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NZ Journal of Physiotherapy July 2006, Vol. 34 (2)56

Anatomy in Practice

Thoracic zygapophyial joint palpation

Jon Cornwall DipPhty, bsc(Phyiol), Msc(Anat)PhD Student, Department of Anatomy & Structural Biology

University of OtagoNew Zealand

suan Mercer bPhty(Hon), Msc, PhDAssociate Professor, School of Biomedical Sciences

The University of Queensland, Australia

AbsTRACTIt is widely accepted that structures in the thoracic region of the vertebral column

are a potential source of pain. Palpation of thoracic zygapophysial joints is therefore

frequently performed during both assessment and treatment of this region. With less

research investigating the thoracic spine than either cervical or lumbar regions, its

unique morphology is often not considered in detail when describing techniques of

manual treatment and assessment. This article addresses vertebral and paravertebral

morphology that may affect accurate palpation of the thoracic zygapophysial joints,

and so highlights practical considerations for clinicians who utilise such procedures.

Cornwall J, Mercer s (2006): Thoracic Zygapophyial joint palpation. New Zealand

Journal of Phyiotherapy 34(2): 56-59.

Keyword: thoracic zygapophyial joint, palpation, clinical anatomy.

INTRODUCTION

Palpation of the vertebral column is routinelyused in the diagnosis and treatment of disordersarising from the spine (Greenman 2003, Maitlandet al 2001, Najm et al 2003). During assessmentclinicians palpate spinal levels to identify painfulsegments, changes in joint motion and local changesin tissue texture (Greenman 2003, Maitland et al2001, Najm et al 2003). The information gathered

in this way contributes to the formation of thediagnosis. However, fundamental to an accuratediagnosis is the ability to correctly identifyanatomical structures ( Greenman 2003, Maitlandet al 2001, Mercer and Rivett 2004,).

One of the commonly assessed and treatedstructures of the vertebral column is thezygapophysial joint (Maitland et al 2001), and inthe thoracic region these joints have recently beendocumented as a source of symptoms ( Dreyfusset al 1994, Manchikanti et al 2004, Wall et al1999). For example, a prevalence rate of 42% for

pain arising from the thoracic zygapophysial jointswas found in a group of patients presenting withchronic thoracic pain (Manchikanti et al 2004).Manual therapists are said to be able to diagnoseconditions such as restrictions of zygapophysialjoint movement (Maitland et al 2001). Treatmentfor such segmental dysfunction involves theapplication of posterior-anterior (PA) mobilisationtechniques, where the motion of a restricted jointsegment is purportedly restored (Greenman 2003,Maitland et al 2001). The facilitation of thisrestricted movement is alleged to occur through theapplication of targeted manual force in the plane ofthe joint (Maitland et al 2001). These assessmentand treatment techniques require that the therapistcan accurately identify the joints in question andcan apply forces at the appropriate orientation.

There are a variety of factors that can inuencethe accuracy of palpation in each region of the spine(Cornwall & Mercer 2004, Dvorak 1998, Najm et al2003). These factors relate to both the morphologyof the vertebral segments and to the gross anatomyof the adjacent tissues (Cornwall & Mercer 2004).For palpation to be as effective as possible it mustbe undertaken in the context of the spinal regionbeing assessed. This article therefore addresses

the concerns that specically arise with palpationof the thoracic zygapophysial joints. Issues thatnecessitate consideration when this procedureis used during manual therapy assessment andtreatment are identied.

MORPHOLOGY

There are eleven pairs of thoracic zygapophysialjoints, with one pair located between each vertebrallevel. These joints contribute to the oor of theparavertebral gutter, the region between thespinous and transverse processes (Clemente 2006,

Moore et al 2006, Rosse et al 1997, Standring 2005)(Figure 1). In the cervical and lumbar regions thisgutter is shallow, formed mainly by the laminaeand articular pillars, whereas in the thoracic regionthe gutter is deeper and broader, being formedby the laminae, articular pillars and transverseprocesses. The thoracic transverse processes alsoarticulate with the tubercle of the dorsal surface ofthe adjacent rib (Standring 2005) (Figure 1).

Due to the contour of the thoracic laminaeand general orientation of the articular processesthe zygapophysial joints appear to lie at, closeto the spinous processes with the prominentcostotransverse joints lying more laterally (Figure1). An informal measurement of six plastinatedvertebral columns revealed that the mid-point ofthoracic zygapophysial joints lay, on average, ten


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NZ Journal of Physiotherapy July 2006, Vol. 34 (2) 57

millimetres from the lateral edge of the adjacentspinous process. These measurements were takenin the coronal plane.

When viewed from behind the most supercialpart of the zygapophysial joint is the inferiorarticular process of the immediately superiorvertebra. At each level the articular facet of eachsuperior articular process passes deep (or moreanterior) to the inferior articular process of the

vertebrae immediately above (Moore & Dalley2006, Rosse & Gaddum-Rosse 1997, Standring2005) (Figure 2). The distal tip of the inferiorarticular process therefore abuts the lamina of theimmediately inferior vertebra, where the joint line isobserved between the two bones (Figures 2 & 3).

Classic anatomical texts (Moore & Dalley 2006,Standring 2005) have stated that the angle at whichthe joint surfaces of thoracic zygapophysial jointsarticulate lies close to the coronal plane. A moreprecise description was provided by Davis (1959)who stated that in the thoracic spine the superiorarticular facets face posteriorly, slightly superiorlyand slightly laterally (Figure 4). As demonstratedin Figure 2 the orientation of the articular facetsin the sagittal plane varies throughout the thoracicregion. Valencia (1994) reported these changesin orientation with respect to the horizontal,describing a 600orientation in the upper thoracicregion changing to 900in the midthoracic regionand almost 00at lower thoracic levels.

Lying between the skin and zygapophysial jointsare layers of subcutaneous tissue and muscle.Immediately below the subcutaneous tissue liesthe lower bres of trapezius, which attaches to

all thoracic spinous processes (Johnson et al1994) (Figure 1 & 4). Lying under the caudalhalf of the lower trapezius muscle are, supercialto deep, the bres of the latissimus dorsi muscle

Figure 1. Tranvere ection through the T2 verteralody howing the mucle overlying the zygapophyial

joint and paraverteral gutter. Red arrow:zygapophyial joint; R: ri; TP: tranvere proce; ss:

emipinali; M: multidu; RH: rhomoid; T: trapeziu.

Figure 2. Paraagittal ection through the thoracicpine, highlighting the orientation and location of the

zygapophyial joint. Note how the inferior articularproce overlap the ujacent uperior articular

proce, the changing orientation of the joint (red

arrow), and the varying depth of the zygapophyialjoint eneath the kin. Red arrow: zygapophyial

joint (from L to R) at T9/10, T6/7, T2/3. segmental levelof thoracic verteral ody indicated y numer.

Figure 3. Doral view of the mid-thoracic verteralcolumn with the overlying mucle removed. Note

the lack of readily identiale or palpale landmarkover the doral urface of the zygapophyial joint

and adjacent lamina. Red arrow indicate joint lineetween T8/9 and T9/10 zygapophyial joint; TP10:

tranvere proce T10; T9, T8, T7: pinou procee ofrepective verterae; L: lamina of T9 vertera; blue

pin: interpinou pace.

Figure 4. Tranvere ection through the level of

T9/10 dic, highlight the thickne of the muculature

lying within the paraverteral gutter aove thezygapophyial joint. Note the poterior and lightly

lateral orientation of the facet of the uperior articular

proce. Red arrow: zygapophyial joint; CV:cotoverteral joint; M: multidu; LO: longiimu;TR: trapeziu; ss: emipinali thoraci / pinali; IL:

iliocotali.


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NZ Journal of Physiotherapy July 2006, Vol. 34 (2)58

or the aponeurotic bres of the posterior layerof the thoracolumbar fascia (Figure 4). Furthersuperiorly the remaining muscles to be consideredare rhomboid minor and major, serratus posteriorsuperior and splenius cervicis (Clemente 1987,Moore & Dalley 2006, Rosse & Gaddum-Rosse1997, Standring 2005).

More intimately associated with the paravertebral

gutter are the short and long rotatores, overlaid bymultidus, semispinalis cervicis and semispinalisthoracis (Hollinshead 1969). Fascicles from therotatores, multidus and semispinalis musclespass between one and six segments before insertinginto a transverse process (Clemente 2006, Moore &Dalley 2006, Rosse & Gaddum-Rosse 1997). Whileclosely approximating the spinous processes, thevery slender spinalis thoracis runs between theT11-L3 spinous processes to insert into a variablenumber of the upper thoracic spinous processes,usually between the level of T4 and T8 (Hollinshead1969). The only additional muscle that may be

considered is the longissimus thoracis, overlyingthe costotransverse regions but lying lateral tosemispinalis thoracis (Bogduk 1994) (Figure 4).Embedded in areolar tissue the thoracic dorsal ramiaccompanied by arteries and veins passes over thedorsal aspect of the multidus muscle covered bybres of semispinalis (Chua & Bogduk 1995).

CLINICAL IMPLICATIONS

Many manual therapy techniques are based ona mechanical paradigm (Mulligan 1995, Maitlandet al 2001), where restrictions in joint movement

are facilitated by the application of manual forceto symptomatic joints. This facilitation is said tooccur when force is applied that aids the movementof contributing articular facets in the directionto which the zygapophysial joint motion is mostinhibited. In this way, the joint is said to bemobilised (Maitland et al 2001). Essential to thisparadigm is a precise knowledge of joint margins,so that force may be directed to the symptomaticjoint(s).

The plane in which the zygapophysial joint liesmust also be identied. This is because facilitation

of joint movement is said to be most effectivelyachieved through manual force that is directedparallel to the plane of the joint (Maitland et al2001). Therefore, for facilitation of zygapophysialjoint motion in the thoracic spine, PA proceduresin this region should direct force in the plane ofthe joint, and not directly in a PA direction. Thedirection of applied force will also be individualto different parts of the thoracic spine, as thesuperior, middle and inferior regions all exhibitdifferent orientations of the zygapophysial joints.Therefore, precise identication of both the jointline and the plane of the joint is necessary to

facilitate appropriate manual therapy interventionas suggested by Maitland et al (2001) and utilisedby clinicians (Mulligan 1995, Jull et al 2002, Lee2004).

Given that the zygapophysial joints lie in theparavertebral gutter, beneath various layers ofsubcutaneous fat and dorsal musculature, it seemsunlikely that the joint line will be readily palpable(Figures 1 & 4). In addition, the similarity in coronalplane orientation of the dorsal surface of the inferiorarticular facet and the adjacent laminae adds tothis difculty: distinguishing between the lamina

and the projecting aspect of the inferior articularfacet using palpation would be problematic. Figure3 highlights the congruence between the laminaeand zygapophysial joints, indicating the paucity of areadily palpable bony landmarks that could facilitateprecise identication of the zygapophysial joints.

These clinically applied anatomical descriptionshighlight the difficulty in accurately palpatingstructures of the thoracic spine, thereby confoundingthe application of PA mobilisation techniques asoutlined by Maitland et al (2001). As suggested byDvorak (1998) palpation under uoroscopy wouldconrm whether the painful level was accurately

located and indicate the orientation of the jointin question. Investigations into the validity of PAtechniques in mobilising vertebral segments alongthe plane of the joint could also be undertaken.

CONCLUSION

It has been demonstrated that the thoraciczygapophysial joints are a potential source of pain(Dreyfuss et al 1994, Manchikanti et al 2004,Wall & Melzack 1999). However it is unlikely,given the morphology and location of the thoraciczygapophysial joints, that individual joints can

be reliably palpated. This becomes problematicwhen assessing the thoracic region, or utilisingtechniques (such as PA mobilisations) that rely oneither joint line or articular process identication.Techniques based on such approaches also needto be re-examined in light of the plane in which thejoints lie, so the application and direction of anymanual force is appropriately applied.

Key Point

The morphology of the thoracic zygapophysialjoints leads to difculty in accurate palpation.

Thoracic zygapophysial joints lie on the oor of the

thoracic paravertebral gutter, overlaid by aseries of dorsal muscles.The orientation of the thoracic zygapophysial joints

varies along the vertebral column.

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PA (Eds): Rheumatology. Baltimore: Mosby, pp. 1-14.Chua WH, Bogduk N (1995): The surgical anatomy of thoracic

facet denervation.Acta Neurochirurgica136: 140-144.Clemente CD (2006): Anatomy: A Regional Atlas of the Human

Body. Munchen: Urban and Schwarzenberg, pp 1-640.Cornwall J, Mercer S (2004): Anatomy in practice: Lumbar

zygapophysial joint Palpation. New Zealand Journal ofPhysiotherapy32: 140-142.

Davis PR (959): The medial inclination of the human thoracicintervertebral articular facets. Journal of Anatomy, 93: 68-74.

Dreyfuss P, Tibiletti C, Dreyer SJ (1994): Thoracic zygapophysealjoint pain patterns: A study in normal volunteers. Spine 19:807-811.


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Dvorak J (1998): Epidemiology, physical examination, andneurodiagnostics. Spine23: 2663-73.

Greenman PE (2003): Principles of Manual Medicine. (3rd ed.)Philadelphia: Lippincott Williams and Wilkins, pp. 1-700.

Hollinshead WH (1969): Anatomy for Surgeons: Volume 3. TheBack and Limbs. (2nded.) London: Harper & Row, pp. 1-894.

Johnson G, Bogduk N, Nowitzke A, House D (1994): Anatomyand actions of the trapezius muscle. Clinical Biomechanics9: 44-50.

Jull G, Trott P, Potter H, Zito G, Niere K, Shirley D, Emberson J,Marschner I, Richardson C (2002): A randomized controlled

trial of exercises and manipulative therapy for cervicogenicheadache. Spine27: 1835-1843.Lee D (2004): Thoracic pain limiting a patients secretarial work

and sport. In: Jones MA, Rivett DA (Eds): Clinical Reasoningfor Manual Therapists. Edinburgh: Elsevier, pp. 149-160.

Maitland G, Hengeveld E, Banks K, English K (2001): MaitlandsVertebral Manipulat ion. (6th ed.) Oxford: Butterworth-Heinemann, pp 1-499 .

Manchikanti L, Boswell MV, Singh V, Pampati V, Damron KS,Beyer CD (2004): Prevalence of facet joint pain in chronicspinal pain of cervical, thoracic, and lumbar regions. BMCMusculoskeletal Disorders5: 1-9.

Mercer S, Rivett DA (2004): Clinical anatomy serving manualtherapy.Manual Therapy9: pp. 59.

Moore KL, Dalley AF (2006): Clinically Oriented Anatomy. (5th ed.)

Baltimore: Lippincott Williams and Wilkins, pp. 1-1209.Mulligan B (1995): Manual Therapy: NAGS, SNAGS, MWMS

etc. (3rd ed.) Wellington: Plane View Services Ltd, pp. 1-40.Najm WI, Seffinger MA, Mishra SI, Dickerson VM, Adams

A, Reinsch S, Murphy LS, Goodman AF (2003): Contentvalidity of manual spinal palpatory exams - A systematicreviewBMC Complementary and Alternative Medicine3. doi:10.1186/1472-6

Rosse C, Gaddum-Rosse P (1997): Hollinsheads Textbook ofAnatomy. (5th ed.) Philadelphia: Lippincott - Raven, pp.1-902.

Standring S (Ed.) (2005): Grays Anatomy. The AnatomicalBasis of Clinical Practice. (39th ed.) Edinburgh: Elsevier,pp. 1-1600.

Valencia F (1994): Clinical anatomy and biomechanics of thethoracic spine. In: Boyling JD, Palastanga N (Eds): GrievesModern manual Therapy. The Vertebral Column. Edinburgh:Churchill Livingstone, pp. 73-84.

Wall PD, Melzack R (1999): Textbook of Pain. (4th ed.) Edinburgh:Churchill Livingstone, pp. 1-1280.

ADDRESS FOR CORRESPONDENCEJon Cornwall, Department of Anatomy & Structural Biology,

University of Otago, Dunedin, New Zealand. Email: jon.cornwall@

anatomy.otago.ac.nz. Phone: 03 479 7362, Fax: 03 479 7254.

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