Document Server@UHasselt > Research > Faculty of Medicine > Morphology > Functional Morphology >

Title: LOWER ARM AND HAND MUSCLES IN FOCAL DYSTONIAS - SOME ANATOMICAL AND THERAPEUTIC ASPECTS

Authors: VAN ZWIETEN, Koos Jaap Lambrichts, Dries Nackaerts, Katrien HAUGLUSTAINE, Stephan SCHMIDT, Klaus BEX, Geert Jan MEWIS, Alex DUYVENDAK, Wim NARAIN, Faridi Lamur, K. S. LIPPENS, Peter Zinkovsky, A. V. Sholukha, V. A. IVANOV, Alexandre Potekhin, V. V. Piskùn, O. E. Varzin, S. A. ZOUBOVA, Irina

Issue Date: 2008

Publisher: Saint-Petersburg State Polytechnical University,

Citation: Varzin, S.A. & Taraskovskaya, O.Y. (Eds.) Transactions of the 3rd All-Russian Scientific Practical Conference with international participants “Health - the base of human potential: problems and ways to their solution”. November 25 - 27, 2008, Saint-Petersburg State Polytechnical University, Saint-Petersburg, Russia. p. 353-363.

Abstract: Computer simulation of normal goal-oriented motion of human lower arm and hand may be also successfully applied in studying movement disorders, known as focal dystonias. Upper limb focal dystonia includes disturbed muscle tension balances, leading to painful, impaired and often aberrant motions. In their attempts to trace the backgrounds of this disorder, several authors have stressed the importance of the brain primary somatosensory cortex, and its role in brain-mapping. This turns out to be especially relevant during learning processes of new motor skills like practising by musicians. The present overview however will mainly analyse musculoskeletal mechanisms of arm and hand movements, with regard to their kinematics in repetitive motions. We will concentrate on pronation and supination movements of the lower arm during repeated shifting of the hand, as in handling a computer mouse, and focus on the maintaining of stable finger position during PC mouse scrolling. Physical therapy (PT) already proved itself useful in treating these focal dystonias, also known as repetitive strain injury (RSI). As an adjuvant to PT, we wish to propose local vibration therapies. Encouraging results of such a treatment, emanating from a recent pilot-study, are presented in conclusion.

ISBN: 978-5-7422-2020-6

Appears in Collections: Databases and Theoretical Computer Science Biomedical Research Institute (BIOMED) Functional Morphology

353

LOWER ARM AND HAND MUSCLES IN FOCAL DYSTONIAS - SOME ANATOMICAL AND THERAPEUTIC ASPECTS

K. J. van Zwieten 1, D. Lambrichts 2, K. Nackaerts 2, S. Hauglustaine 2,

K. P. Schmidt 1, G. J. Bex 1, A. Mewis 3, W. Duyvendak 4, F. H. M. Narain 5, K. S. Lamur 5, P. L. Lippens 1, A. V. Zinkovsky 6, V. A. Sholukha 6, A. A. Ivanov 6, V. V. Potekhin 6, O. E. Piskùn 6, S. A. Varzin 6, I. A. Zoubova 6

1. Department of Anatomy, BioMed, University of Hasselt, transnational University Limburg, Diepenbeek, Belgium

2. Department Gezondheidszorg, Opleiding Kinesitherapie, Provinciale Hogeschool Limburg, Hasselt, Belgium

3. Clinical Microbiology Laboratory, Virga Jesse Hospital, Hasselt, Belgium

4. Department of Neurosurgery, Virga Jesse Hospital, Hasselt, Belgium 5. Department of Anatomy, University of Suriname, Paramaribo, Suriname 6. Department of Biomechanics and Valeology, Saint-Petersburg State

Polytechnical University, Saint-Petersburg, Russia

INTRODUCTION AND SUMMARY

Computer simulation of normal goal-oriented motion of human lower arm and hand may be also successfully applied in studying movement disorders, known as focal dystonias 1 - 3). Upper limb focal dystonia includes disturbed muscle tension balances, leading to painful, impaired and often aberrant motions. In their attempts to trace the backgrounds of this disorder, several authors have stressed the importance of the brain primary somatosensory cortex, and its role in brain-mapping 14). This turns out to be especially relevant during learning processes of new motor skills like practising by musicians 15, 22). The present overview however will mainly analyse musculoskeletal mechanisms of arm and hand movements, with regard to their kinematics in repetitive motions. We will concentrate on pronation and supination movements of the lower arm during repeated shifting of the hand, as in handling a computer mouse, and focus on the maintaining of stable finger position during PC mouse scrolling 23, 24). Physical therapy (PT) already proved itself useful in treating these focal dystonias, also known as repetitive strain injury (RSI) 24). As an adjuvant to PT, we wish to propose local vibration therapies 29). Encouraging results of such a treatment, emanating from a recent pilot-study, are presented in conclusion 31).

354

LOWER ARM - COMPARATIVE ANATOMICAL BACKGROUNDS

Locomotion in small arboreal quadrupeds that are generally regarded as precursors of lower primates includes rotational movements in shoulder, upper and lower arm, wrist and hand. A basic functional demand in those species is: keeping each hand alternatingly in contact with the substratum, while the body moves forward in the parasagittal plane. By this motion, the relative conservative feature of lateral rotation by the upper arm at the onset of each stance (to end up in a medial rotation at late stance) coincides with a decrease of crossing by the radius over the ulna, as long as propulsion stroke proceeds 4 - 6). In the opossum lower arm, this uncrossing or supination of the radius respective to the ulna is accentuated by a widening of the spatium interosseum antebrachii, as well as by early take-offs of the flexed 4th and 5th digits (Figure 1).

Figure 1 Figure 2 Figure 3

Fig. 1 Walking opossum, top to base: propulsion includes lower arm supination Fig. 2 Man, start propulsion stroke: medial rotation (arrow) of humerus (yellow) Fig. 3 In propulsion: lateral rotation humerus, radius (red) crosses (*) ulna (blue)

In many primates including man, mainly as a consequence of the different

positions of their shoulder blades, such rotational phenomena as the ones described above present themselves differently. Propulsion stroke by the arm, as long as the hand stays palm downwards in contact with the substratum, may show an increasing lateral rotation of the upper arm, while the radius gradually crosses the ulna 7 - 8). The crossing itself is defined as pronation of the lower arm. Hereby the spatium interosseum antebrachii (seen from distally to proximally) becomes narrower, as the radius gradually overlaps the ulna (Figures 2 and 3).

355

LOWER ARM - THE SITUATION IN MODERN MAN

Quite comparable phenomena do occur when a seated person shifts his hand, palm downwards, to and from his body, e.g. by moving the computer mouse over a mouse-pad. By repeating these movements numerous times daily, the muscles of trunk, shoulder, upper and lower arm may start to display focal dystonia. In order to study one of the muscles that are possibly involved in developing such a dystonia, the pronator teres muscle was selected, based on its obvious capacity (just by muscle contraction) to move the radius over the ulna, thus narrowing spatium interosseum antebrachii, as a hallmark of pronation 13).

Remarkably, a recent 2008 study on lower arm muscle activities while handling various types of PC mouse, left such actions of m. pronator teres out of consideration, although the various positions of lower arm pronation were taken into account 9).

LOWER ARM - THEORETICAL KINEMATIC ANALYSIS

Anatomical and kinematic features of m. pronator teres were investigated

theoretically, in human anatomical specimens by dissection, with use of magnifying loupes, and by roentgenphotogrammetry. In a small number (5) of anatomical specimens of the lower arm of otherwise normal subjects, as currently used during the practical courses of anatomy organized by our department, the pronator teres muscle was brought into view, and its various fibre bundles were carefully dissected 11). The humeral head and the ulnar head of m. pronator teres fuse, after which their common tendon inserts on the tuberositas pronatoria of the radius (Figure 4). The precise position of pronator teres muscle was identified in anteroposterior radiographs, by means of lead markings attached to the various muscle fibre bundles prior to radiography (Figure 5). Pronator teres muscle was represented by straight lines between its markers, indicated on tracings of these radiographs (Figure 6). In each tracing, the average position of such lines representing the vector of m. pronator teres was introduced, to be used for a mathematical vector analysis of forces.

During pronation the radius approximately follows a conical path. The apex of this virtual cone is located at the head of the radius, while the centre of the circular base of this cone is the ulnar styloid process. The axis of this cone may be regarded as identical to the axis of forearm pronation and supination 10). In the radiographs, the centre of the articular facet of the head of the radius, and the tip of the ulnar styloid process, served as the bony landmarks concerned. In the tracings the axes of pronation and supination were also introduced, by drawing a straight line connecting these two points.

A two-dimensional representation of this cone, which is an isosceles triangle, was used to introduce average pronator teres’ line of action (red, Fig.7)

356

at one slant side of this triangle, starting from the point representing tuberositas pronatoria of the radius in pronation. The direction of this vector was then used to estimate the muscle’s contribution to lower arm pronation (small green arrow, Figure 7). Mathematically, resolution of forces revealed - at least theoretically - that the effective contribution of m. pronator teres to forearm pronation constitutes about 25 % of its contribution to forearm flexion at the elbow 12, 13).

The result of this analysis therefore suggests that, also in the acquisition of lower arm focal dystonia and repetitive strain injuries, pronator teres muscle might play only a minor role.

Figure 4 Figure 5 Figure 6

Figure 7

Fig. 4 Human lower arm: m. pronator teres (arrows) from humerus (yellow) and

ulna (blue) inserts at radius (red) Brand-Hollister (‘93) essentially adapted Fig. 5 Arm anatomical specimen, X-ray, lead markers indicate m. pronator teres Fig. 6 In positive, pro-supination-axis (red) and m. pronator teres’ course added Fig. 7 Triangle represents “pronation-path”, plus m. pronator teres’ vector (red)

357

HANDS AND FINGERS - COMPARATIVE ANATOMICAL ASPECTS

Experimental studies on the brain primary somatosensory cortex in primates, as related to repetitive strain injuries, have currently made use of the hands of a New World primate, Aotus in particular 14). With regard to the use of fingers in such cebid genera however, the next remarks should be kept in mind.

The fingers of most primates of the New World have a compact extensor assembly without such distinct distribution into bundles, as in higher primates, including man 16). This was demonstrated in the fingers of Callitrichidae and Cebidae, especially in Aotus (Figure 8). In these primates it was expected that, in proximal interphalangeal flexion, the lateral parts (l p, Fig. 8) of their compact extensor assembly would not be displaced palmarward as easily, respective to its medial part (m p, Fig. 8), as in higher primates including man 17). Absence of coupled interphalangeal flexion in some kinds of their grips would be the result.

In their behaviour, these New World primates including Aotus (i.e. the owl monkey) do show hand postures in which proximal interphalangeal flexion is coupled notably to distal interphalangeal extension or even hyperextension, leading to effective adhesive grips of the hands to large branches 19) (Figure 9).

In prosimians too, the extensor assembly is compact 18, 20). This supports the existence of a relationship between a simple structure of the extensor assembly and the prosimian-like nature of interphalangeal coupling.

Figure 8 Figure 9

Fig. 8 Aotus finger transverse Ø at proximal interphalangeal (PIP)-level, see text Fig. 9 Aotus adhesive grip: distal interphalangeal (DIP)-extension & PIP-flexion

THE FREELY MOVING HUMAN FINGER

A functional analysis of the human extensor assembly in relation to

coupled interphalangeal motion was made by means of a kinematic model. In

358

this model, the two interphalangeal joints can be flexed simultaneously, as normally occurs in various types of grips and precision handling. A movie-sequence of simulation by mathematical modelling of such finger flexion was recently published 21, 22). One initial frame from this sequence in particular is depicted in the diagram of the slightly bowed finger, in a stabilized position (Figure 10). Such stability of the freely moving finger is essential for finely tuned finger movements, e.g. by practising musicians. Any muscular imbalance may eventually lead to focal hand dystonia 23, 24).

Apart from practising a musical instrument, finger scrolling while handling a computer mouse also requires such finger stability. Recent studies dedicated to mouse scrolling kinematics have underlined the importance of good muscular balances, for finger stability, as well as during finger mobility 25, 27).

Figure 10

Fig. 10 Kinematic model: stable human finger in a slightly bowed position, lines representing tendons - extensor assembly distributed into separate bundles

THE FINGER IN NEUROPATHY - DIAGNOSTIC ASPECTS

Part of muscular imbalances in hand and finger may result from

compression neuropathies in which one or more motor nerves are damaged, leading to paralysis of the muscles concerned. Apart from PC workers, professional musicians may be the subjects of such disorders 23, 26). With regard to hand and fingers, a certain incoordination of interphalangeal motion may be present too, in such neuropathies.

To analyse the finger motor patterns before and after therapy, forward and reverse mathematical modelling, by means of the abovementioned kinematic finger model was successfully applied 28).

UPPER EXTREMITY REPETITIVE STRAIN INJURIES -

THERAPEUTIC ASPECTS

To conclude, we wish to refer to a pilot study after the effects of vibration therapy on subjects suffering RSI symptoms of the upper extremity, in

359

comparison to classical rehabilitation therapy. 5 subjects in the control group underwent classical rehabilitation, 5 subjects in the experimental group received vibration therapy. A pre-post design was used to measure upper extremity movements for strength, and the McGill pain questionnaire for pain sensation. During 4 weeks, both groups received 8 sessions of therapy consisting of strength exercises. As a result, there was an average strength increase for both groups during the intervention. Indications of pain sensation decreased for both groups, though more significantly so for the group receiving vibration therapy. Vibration therapy can therefore be a significant adjunctive therapy for RSI.

In increasing strength and decreasing pain, it is more significant than classical rehabilitation 29).

CONCLUDING REMARKS

The present overview, highlighting some of the possible anatomical

backgrounds of upper extremity repetitive strain injuries and dystonias, has left many questions unanswered. An obvious need is felt also, to gather data on a person’s ability to manage the relatively monotonous handling of a computer.

Such studies may advantageously include anatomical aspects, e.g. anthropometric measurements as well as highly sensitive registrations of finely tuned hand movements.

The abovementioned presentation clearly shows that until now, univocal explanations of mechanisms behind focal dystonias are hard to deliver. This is generally so in diagnostics, but also in pathophysiology and therapy. Thorough kinematical analyses might be able to unravel some of the enigmas still existing.

Recently, some doubt arose regarding the effectiveness of vibration therapies in systemic neuropathies 30). Nevertheless, strong indications currently exist that peripheral and local pain and muscular weakness can be effectively treated with the help of local vibration training, respectively by the application of electrovibrostimulation, preferably in a proper way, ad modum Zinkovsky 31).

REFERENCES

1) Sholuha VA, Zinkovsky, AV, Ivanov AA, Lippens PL and van Zwieten KJ (1996) Computer simulation of goal-oriented motions of the human arm. In: Van der Perre, Georges, Van Audekerke, Remi, Lowet, Geert and Vander Sloten, Jos (Eds.) 10th Conference of the European Society of Biomechanics, Leuven, August 28-31, 1996, Book of Abstracts, 342 2) van Zwieten KJ, Lippens PL, Sholukha VA, Zinkovsky AV and Duyvendak W (1998) Application model of goal oriented movement synthesis of the human finger. In: Schuind, F. (Ed.) Brussels International Symposium Advances in

360

Upper Extremity Osteosynthesis, April 17-18, 1998, Genval - Brussels, Book of Abstracts, 176 3) Inzelberg R, Flash T, Schechtman E and Korczyn AD (1995) Kinematic properties of upper limb trajectories in idopathic torsion dystonia. Journal of Neurology, Neurosurgery, and Psychiatry, 58, 312-319 4) Jenkins FA Jr. (1971) Limb posture and locomotion in the Virginia opossum (Didelphis virginiana) and in other non-cursorial mammals. Journal of Zoology (London), 165, 303-315 5) Jenkins FA Jr. and Goslow GE Jr. (1983) The Functional Anatomy of the Shoulder of the Savannah Monitor Lizard (Varanus exanthematicus). Journal of Morphology, 175, 195-216 6) Gambaryan PP (2000) A unique case of convergency in mammals. Annual Reports of the Zoological Institute, Russian Academy of Sciences, Universitetskaya nab., 1, St. Petersburg, Russia 7) Schmidt M and Fischer MS (2000) Cineradiographic Study of Forelimb Movements During Quadrupedal Walking in the Brown Lemur (Eulemur fulvus, Primates: Lemuridae). American Journal of Physical Anthropology, 111, 245-262 8) Larson SG and Stern JT (2006) Maintenance of Above-Branch Balance During Primate Arboreal Quadrupedalism: Coordinated Use of Forearm Rotators and Tail Motion. American Journal of Physical Anthropology, 129, 71-81 9) Oude Hengel KM, Houwink A, Odell D, van Dieën JH and Dennerlein JT (2008) Smaller external notebook mice have different effects on posture and muscle activity. Clinical Biomechanics, 23, 727-734 10) Kapandji IA (1982) The Physiology of the Joints, Volume One, Upper Limb, 5th Edition. Churchill Livingstone, Edinburgh London Melbourne and New York 11) Brand PW and Hollister A (1993) Clinical Mechanics of the Hand, 2nd edition. Mosby Year Book, St. Louis 12) Lambrichts D (2004) Kwantitatieve en morfologische beschrijving van de m. pronator teres in verband met pro- en supinatie mechanismen tijdens bewegingen van de hand over een horizontaal vlak. MSc Thesis in Physical

361

Therapy, Provinciale Hogeschool Limburg, Departement Gezondheidszorg, Opleiding Kinesitherapie, Hasselt 13) van Zwieten KJ, Lippens PL, Schmidt KP, Duyvendak W, Lamur KS, Narain FHM, Zubova IA, Varzin SA, Piskùn OE and Zinkovsky AV (2007) Pronator teres muscle and repetitive strain injuries. In : Transactions of the 2nd All-Russian Scientific Practical Conference with International Participants “Health as the basis of human potential: problems and how to solve them” October 2 - 4, 2007, Saint-Petersburg, Russia. Eds: Varzin SA and Tarasovskaia OU. Saint-Petersburg State Polytechnical University, Saint-Petersburg, Russia, 250-251 14) Byl NN, Merzenich MM, Cheung S, Bedenbaugh P, Nagarajan SS and Jenkins WM (1997) A Primate Model for Studying Focal Dystonia and Repetitive Strain Injury: Effects on the Primary Somatosensory Cortex. Physical Therapy, 77, 3, 269-284 15) Pujol J, Roset-Llobet J, Rosinés-Cubells D, Deus J, Narberhaus B, Valls-Sole J, Capdevila A and Pascual-Leone A (2000) Brain Cortical Activation during Guitar-Induced Hand Dystonia Studied by Functional MRI. NeuroImage 12, 257-267 16) Landsmeer JMF and van Zwieten KJ (1974) Observations on the extensor assembly in some primate species. Journal of Anatomy, 117, 1, 204-205 17) van Zwieten KJ (1978) The extensor assembly of the finger in some primate species. Journal of Anatomy, 126, 2, 433-434 18) van Zwieten KJ (1985) The extensor assembly of the finger in lower primates. Journal of Anatomy, 140, 3, 533-534 19) Krakauer E, Lemelin P and Schmitt D (2002) Hand and Body Position During Locomotor Behavior in the Aye-Aye (Daubentonia madagascariensis). American Journal of Primatology, 57, 105-118 20) Soligo C (2005) Anatomy of the Hand and Arm in Daubentonia madagascariensis : A Functional and Phylogenetic Outlook. Folia Primatologia, 76, 262-300 21) Sholukha VA, van Zwieten KJ, Lippens PL and Zinkovsky AV (1998) Finger tendons kinematics assessing from motion dynamics computer oriented modeling. Journal of Biomechanics, 31, 1, 29

362

22) van Zwieten KJ, Potekhin VV, Lippens PL, Sholukha VA, Schmidt KP and Zinkovsky AV (2006) The influence of finger position on percussion sounds. In: Proceedings of the 13th International Congress on Sound and Vibration (ICSV 13), July 2-6, 2006, Vienna, Austria. Eds.: Eberhardsteiner J, Mang HA and Waubke H. Vienna University of Technology, Austria 23) Newmark J and Hochberg FH (1987) Isolated painless manual incoordination in 57 musicians. Journal of Neurology, Neurosurgery, and Psychiatry, 50, 291-295 24) Butler K and Rosenkranz K (2006) Focal Hand Dystonia Affecting Musicians. The British Journal of Hand Therapy, 11, 3, 72-78 25) Ugbolue UC, Christophel TH, Baker NA and Li ZM (2005) Kinematics of mouse scrolling. ISB XXth Congress - ASB 29th Annual Meeting, July 31 - August 5, Cleveland, Ohio, 272 26) Cheung JPY, Fung B, Ip WY and Chow SP (2008) Occupational repetitive strain injuries in Hong Kong. Hong Kong Medical Journal, 14, 4, 296-302 27) Lee DL, McLoone H and Dennerlein JT (2008) Observed finger behaviour during computer mouse use. Applied Ergonomics, 39, 107-113 28) van Zwieten KJ, Lippens PL, Gelan J, Adriaensens P, Schmidt KP, Thywissen C and Duyvendak W (2008) Coordination of interphalangeal flexion in the human finger. Journal of Hand Surgery - British and European Volume, 33, 1, 170-171 29) Nackaerts K (2006) Whole body vibration as an adjuvant therapy for treating repetitive strain injury (RSI). MSc Thesis in Physical Therapy, Provinciale Hogeschool Limburg, Departement Gezondheidszorg, Opleiding Kinesitherapie, Hasselt 30) Broekmans T, Alders G, Roelandts M, Feys P, Meesen R, Charlier C, Van Hoof E, Stinissen P and Op ‘t Eijnde B (2007) Exercise therapy in multiple sclerosis patients: effects of resistance training, additional electro-stimulation and whole body vibration on muscle functional capacity. Multiple Sclerosis, 13, 131 31) van Zwieten KJ, Verhaegen I, Op ‘t Eijnde B, Zinkovsky AV, Zoubova IA, Schmidt KP and Lippens PL (2007) Electrovibrostimulation during the training of sportsmen, an experimental set-up. Journal of Vibroengineering, 9, 4, 50-54