authors of injury. shoulder concerning the identification of ......viii should however a physician...

Louis PATRY, Occupational Medecine Physician, ErgonomistMichel ROSSIGNOL, Occupational Medecine Physician, Epidemiologist

Marie-Jeanne COSTA, Nurse, ErgonomistMartine BAILLARGEON, Plastic Surgeon

GUIDE TO THE DIAGNOSIS OFWORK-RELATED MUSCULOSKELETAL

DISORDERS3Work-related musculoskeletal injuries are one of the most common occupational

health problems for which physicians are consulted. There is solid scientific evidence thatthese injuries may be occupational in origin.

This guide was designed to help physicians interpret the results of a medicalexamination. By combining the standard clinical assessment procedure with guidelinesconcerning the identification of etiological factors, it helps physicians identify the causeof injury.

AUTHORS

Louis Patry holds a degree in medicine from Laval University anda diploma in ergonomics from the Conservatoire National des Artset Metiers de Paris (CNAM). He is a specialist in occupational medi-cine, an associate member of the Royal College of Physicians andSurgeons of Canada, a professor in McGill University’s Departmentof Epidemiology and Biostatistics and Occupational Health, and con-sulting physician to the Direction de la santé publique (Public HealthDepartment), first in Québec City and currently at the Montréal-Centre board.

Michel Rossignol holds degrees in biochemistry and medicinefrom the University of Sherbrooke, in epidemiology and communityhealth from McGill University, and in occupational medicine fromJohn Hopkins University. He is a professor in McGill University’sDepartment of Epidemiology and Biostatistics and OccupationalHealth, co-director of the Centre for Clinical Epidemiology of theJewish General Hospital of Montréal, and physician-epidemiologistat the Montréal-Centre board of the Direction de la santé publique(Public Health Department).

Marie-Jeanne Costa holds a nursing degree from the Institutd’études paramédicales de Liège and a degree in ergonomics fromthe École Pratique des Hautes Études de Paris. She is an ergonomicsconsultant and has collaborated on several studies of CTDs. She isparticularly interested in the development of participatory ergonom-ics, specifically in the problem-resolution and diagnostic processes.

Martine Baillargeon holds a degree in medicine from theUniversité de Montréal. She is a plastic surgeon and associate mem-ber of the Royal College of Physicians and Surgeons of Canada.After years of practising surgery she is now consulting physician,mainly in the field of musculoskeletal injuries affecting the upperlimb, at the Montréal-Centre board of the Direction de la santépublique (Public Health Board).

ShoulderTendinitis

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DISORDERS

Carpal TunnelSyndrome




Excerpt of the full publication

Translation: Les Services Organon, Steven Sacks

Graphic design: Gérard Beaudry

Illustrations: Marjolaine Rondeau, Medical Illustration Department of the Laval University Hospital Centre (CHUL) Max Stiebel, Instructional Communications Centre (ICC), McGill University

Rear-cover photographs: Gil Jacques

Legal deposit – Bibliothèque nationale du Québec, 1998Legal deposit – National Library of Canada, 1998ISBN 2-921146-72-X Éditions MultiMondes (Original edition: ISBN 2-921146-63-0)© Éditions MultiMondes, 1998

Éditions MultiMondes Institut de recherche en santé 930, rue Pouliot et en sécurité du travailSainte-Foy (Québec) 505, boul. de Maisonneuve OuestCanada G1V 3N9 Montréal (Québec)Tel.: (418) 651-3885 Canada H3A 3C2Fax: (418) 651-6822 Tel: (514) 288-1551 Fax: (514) 288-7636

Régie régionale de la santé et des services sociaux – Montréal-Centre Direction de la santé publique 1301, rue Sherbrooke Est Montréal (Québec) Canada H2L 1M3 Tel.: (514) 528-2400 Fax: (514) 528-2459

Canadian Cataloguing in Publication Data

Main entry under title:Guide to the diagnosis of work-related musculoskeletal injuries

Translation of: Guide pour le diagnostic des lésions musculo-squelettiques attribuables au travail répétitif. Includes bibliographical references. Contents: 1. Carpal tunnel syndrome – 2. De Quervain’s tenosynovitis – 3. Shoulder tendini-tis. Co-published by: Institut de recherche en santé et en sécurité du travail du Québec. ISBN 2-921146-70-3 (v. 1) – ISBN 2-921146-71-1 (v. 2) – ISBN 2-921146-72-X (v. 3)1. Musculoskeletal system – Wounds and injuries – Diagnosis. 2. Overuse injuries – Diagnosis. 3. Carpal tunnel syndrome – Diagnosis. 4. Tenosynovitis – Diagnosis. 5. Tendinitis – Diagnosis. 6. Occupational diseases – Diagnosis. I. Patry, Louis. II. IRSST (Quebec). III. Workplace Safety & Insurance Board.RC925.7.G8413 1998 616.7’075 C98-940950-3



v

preface

The diagnosis of cumulative trauma disorders (CTDs) presents many unique problems, especially for physicians. The absence of precise criteria upon which to establish a clinical diagnosis of CTD or decide whether a musculoskeletal injury is related to occupational factors was noted by several members of the advisory committee supporting an international expert group mandated by the IRSST to review the literature on CTDs*. To remedy this situation, in 1992 the IRSST asked a group of researchers to develop diagnostic guides for carpal tunnel syndrome, De Quervain’s tenosynovitis, and tendinitis of the shoulder.

The project team was initially composed of Louis Patry, occupational physician and ergono-mist, and Michel Rossignol, occupational physician and epidemiologist, but quickly grew and increased the scope of its expertise through the addition of Marie-Jeanne Costa, a nurse with ergonomics training, and Martine Baillargeon, a plastic surgeon. All four team members partici-pated in the drafting of the guides.

These guides were designed to help physicians arrive at a clinical diagnosis and identify the most probable etiological agents. It should be noted that these guides were not designed for administrative or legal purposes and that their reliability has not evaluated by the researchers.

The publication of these guides designed specifically for physicians is one more advance in the IRSST’s efforts to shed light on the phenomenon of cumulative trauma disorders and provide specialists with appropriate tools with which to prevent these injuries and reduce related risk factors.

Jean Yves Savoie

Director general Institut de recherche en santé et en sécurité du travail du Québec

* Hagberg, M., Silverstein, B., Wells, r., Smith, M.J., Hendrick, H.W., carayon, p., pérusse, M. (1995), Work related muscu-loskeletal disorders (WMSDs): a refer ence book for prevention, scientific editors: Kuorinka, I., forcier, L., publishers Taylor and francis, London, 421 pages.



vii

InTroducTIon

This guide is the third in a series of practical summaries of current medical knowledge on mus-culoskeletal injuries with well-documented occupational etiology, namely:

– carpal tunnel syndrome (CTS) – De Quervain’s tenosynovitis – tendinitis of the shoulder

When occupational in origin, these injuries are often referred to as “CTDs”, a term applica-ble to “problems and diseases of the musculoskeletal system that include, among their causes, some factor related to work” (Kuorinka et al., 1995). Whatever term is used to designate them—occupational overuse syndrome (OOS), repetitive strain injuries (RSI) or cumulative trauma di-sorders (CTDs) in English, troubles musculo-squelettiques (TMS), lésions musculo-squelettiques (LMS), lésions musculo-tendineuses (LMS), lésions musculo-tendineuses liées aux tâches répéti-tives, or pathologies d’hyper-sollicitation in French—their defining characteristic is the presence of an injury caused by biomechanical strain due to tension, pressure, or friction which is exces-sively forceful, repetitive, or prolonged.

This guide is designed for physicians who are called upon in the course of their practice to diagnose musculoskeletal injuries and establish the extent to which these injuries are caused by their patient’s work. Its goal is to help physicians arrive at clinical and etiological diagnoses. To this end, the guide first reviews the anatomical, physiopathological, and etiological knowledge upon which diagnosis depends. This is followed by guidelines for the evaluation of symptoms, the conduct of the clinical examination, and the control of potential risk factors related to the development of the injury.

Musculoskeletal injuries may have many causes. For carpal tunnel syndrome (CTS), De Quervain’s tenosynovitis and tendinitis of the shoulder, these include not only occupational, sporting, recreational, and domestic activities, but also specific health problems and conditions. This guide was prepared in response to requests from phy sicians, increasingly preoccupied by CTDs, for information and support on this subject. Although the approach taken emphasizes the documentation of potential occupational risk factors—a subject little discussed in formal medical training—it does not neglect the evaluation of other potential causes of tendinitis of the shoulder.

This guide is meant to be used in a clinical setting. To help physicians collect the infor mation they need to diagnosis the injury and establish its causes, it therefore includes a series of questions, presented in readily identifiable text boxes, for them to ask their patients. These questions were derived from psycho-physical scales used by ergonomists to subjectively evaluate workload (Sinclair, 1992) and medical questionnaires developed for the diagnosis of CTS and the evaluation of functional capacity (Katz et al., 1994; Levine et al., 1993; Rossignol et al., 1995).



viii

Should however a physician remain unable to come to a definitive conclusion about the work-relatedness of an injury after consulting this guide, she or he should continue to seek in-formation which will enable her or him to better evaluate the occupational musculoskeletal strain to which her or his patient is subjected.

Finally, it should be noted that this guide does not address the issues of multiple injuries and the psycho-social aspects of musculoskeletal injuries, important as they may be for the global evaluation of the patient.


ix

TaBLe of conTenTS

Chapter 1 – General Considerations

Terminology .......................................................................................................................................... 1

Epidemiology ........................................................................................................................................ 1

Anatomical Review .............................................................................................................................. 1

Structure of the Shoulder Joint ................................................................................................. 2

Structure of the Tendon ............................................................................................................. 2

Biomechanical Considerations ................................................................................................... 3

Innervation .................................................................................................................................... 5

Physiopathology ................................................................................................................................... 6

Chapter 2 – Etiology

General Description of Risk Factors ................................................................................................ 9

Specific Risk Factors for Shoulder Injuries.................................................................................... 10

Occupational Sources of Musculoskeletal Strain .......................................................................... 10

Strain Related to Sports-related, Recreational and Household Activities ................................. 11

Strain in Musicians ............................................................................................................................. 11

Chapter 3 – Differential Diagnosis

Injury to Structures Surrounding the Rotator Cuff ..................................................................... 13

Subacromial Bursitis .................................................................................................................. 13

Adhesive Capsulitis (Retractile Capsulitis, Frozen Shoulder) .............................................. 13

Shoulder Pathologies ......................................................................................................................... 15

Cervicobrachial Disorders ........................................................................................................ 15

Compression of the Supraclavicular Nerve ........................................................................... 15

Cervical Root Injuries ................................................................................................................ 15

Thoracic Outlet Syndrome ....................................................................................................... 15

Shoulder Instability .................................................................................................................... 16

General and Systemic Pathologies ................................................................................................... 16

Chapter 4 – Clinical Considerations

Symptoms ............................................................................................................................................ 17

Location of Symptoms (Where?) ............................................................................................ 17

Onset of Symptoms (When?) .................................................................................................. 18

Characteristics of Onset (How?) ............................................................................................. 18



x

Impact on Activities of Daily Living .............................................................................................. 18

Impact on Physical Activity .............................................................................................................. 19

Chapter 5 – Recording of Information on Exposure Factors

Occupational History ........................................................................................................................ 21

Previous Work ............................................................................................................................ 21

Current Work .............................................................................................................................. 21

Current Work and Organisational Factors ............................................................................. 22

Sports-related, Recreational and Household Activities ................................................................ 24

Chapter 6 – Physical Examination of the Shoulder

General Evaluation ............................................................................................................................ 25

Specific Evaluation ............................................................................................................................. 27

Supraspinatus Tendinitis ........................................................................................................... 27

Infraspinatus Tendinitis ............................................................................................................. 28

Subscapular Tendinitis and Teres Minor Tendinitis ............................................................. 28

Subacromial Impingement Syndrome ..................................................................................... 29

Rotator Cuff Tear ...................................................................................................................... 32

Tenosynovitis of the Long Head of the Biceps ................................................................... 33

Chapter 7 – Summary of the Evaluation ......................................................................................... 35

Chapter 8 – Guidelines for Therapeutic and Preventive Interventions

Therapeutic Guidelines ..................................................................................................................... 37

Prevention Guidelines ....................................................................................................................... 37

Conclusion ................................................................................................................................................. 39

Bibliography ............................................................................................................................................. 41

List of Figures

Figure 1.1 Structure of the Shoulder Joint ....................................................................................... 2

Figure 1.2 Structure of Tendons ........................................................................................................ 2

Figure 1.3a Muscles and Tendons of the Rotator Cuff (Anterior View) ...................................... 3

Figure 1.3b Muscles and Tendons of the Rotator Cuff (Posterior View) ..................................... 3

Figure 1.4 Course of the Tendon of the Long Head of the Biceps ........................................... 3

Figure 1.5 Action of the Rotator Muscles ........................................................................................ 4

Figure 1.6 Components of Rotary and Coaptation Forces During Shoulder Movements ......................................................................................................................... 4

Figure 1.7 Dermatomes and Sensory Innervation .......................................................................... 5

Figure 1.8 Critical Zone of the Tendons of the Supraspinatus and the Long Head of the Biceps Subjected to Premature Wear ................................................................. 6



xi

Figure 2.1 Interrelation of Risk Factors ........................................................................................... 9

Figure 3.1 Subacromial Bursitis ........................................................................................................ 13

Figure 3.2 Compression of the Supraclavicular Nerve ................................................................ 15

Figure 3.3 Anatomy of the Cervicothoracoscapular Junction .................................................... 15

Figure 3.4 Structures Capable of Causing Shoulder Pain ............................................................ 16

Figure 4.1 Shoulder-Arm Diagrams ................................................................................................ 17

Figure 6.1 Painful Points on the Shoulder ...................................................................................... 25

Figure 6.2 Painful Arcs ...................................................................................................................... 26

Figure 6.3 Resisted Abduction of the Arm .................................................................................... 27

Figure 6.4 Jobe’s Manoeuvre ............................................................................................................. 27

Figure 6.5 Resisted External Rotation of the Forearm ................................................................ 28

Figure 6.6 Patte’s Manoeuvre ............................................................................................................ 28

Figure 6.7 Resisted Internal Rotation of the Forearm ................................................................. 28

Figure 6.8 Mechanism of Impingement ......................................................................................... 29

Figure 6.9 Neer’s Sign ........................................................................................................................ 31

Figure 6.10 Hawkins’ Sign ................................................................................................................... 31

Figure 6.11 Drop-Arm Manoeuvre .................................................................................................... 32

Figure 6.12 Resisted Elevation of the Arm ...................................................................................... 33

Figure 6.13 Resisted Flexion of the Elbow ...................................................................................... 33

Figure 8.1 Therapeutic Intervention Flow-Chart .......................................................................... 38

Figure 8.2 Therapeutic Approach to Tears of the Rotator Cuff ................................................ 38

List of Tables

Table 6.1 Stages of Impingement Syndrome ............................................................................... 30

Table 6.2 Imaging Techniques for Tears of the Rotator Cuff .................................................. 32

Table 8.1 Preventive Approach ....................................................................................................... 37

List of Boxes

Box 1.1 Innervation of the Rotator Cuff and Biceps Muscles ................................................ 5

Box 1.2 Contributory Factors for Tendinitis of the Rotator Cuff and Tenosynovitis of the Long Head of the Biceps ........................................................... 7

Box 2.1 Movements Most Commonly Associated with the Development of Shoulder Tendinitis .......................................................................................................... 12

Box 3.1 Clinical Signs of Subacromial Bursitis ......................................................................... 14

Box 3.2 Clinical Summary of Adhesive Capsulitis .................................................................... 14

Box 4.1 Questions about Activities of Daily Living ................................................................. 18

Box 4.2 Presentation and Clinical Severity of Symptoms ....................................................... 19

Box 5.1 Questions about Previous Jobs ..................................................................................... 21

Box 5.2 General Questions Concerning Occupational Activities and Symptoms Associated with Them ................................................................................ 22



xii

Box 5.3 Questions about Activities that Stress the Shoulder .................................................. 23

Box 5.4 Questions about Work Organisation ............................................................................ 24

Box 5.5 Questions about Sports-related, Recreational, and Household Activities Involving the Shoulders ................................................................................ 24

Box 6.1 General Evaluation .......................................................................................................... 25

Box 6.2 Painful Arcs during Active Abduction of the Arm ................................................... 26

Box 7.1 Clinical Aspects ................................................................................................................ 35



1

Terminology

Shoulder tendinitis is defined clinically as “pain in the shoulder associated with tenderness to palpation over the head of the humerus” (Hagberg and Wegman, 1987) and corresponds to inflammatory and degenerative injuries of the tendons of the rotator cuff and the long head of the biceps. The term “rotator cuff ” is used to designate the tendons of the muscles which originate in the scapula, converge at the head of the humerus where they form a “cuff ”, and insert on the greater or lesser tuberosity. The tendon of the long head of the biceps originates from the superior portion of the glenoid fossa near the supraspinatus tendon and is generally subject to the same strains as the rotator cuff tendons (Pujol et al., 1993).

epidemiology

According to the Bureau of Labour Statistics of the United States, shoulder pain is the second most common complaint—after back pain—reported during clinical consultations; furthermore, the prevalence of occupational shoulder pain is increasing greatly (Sommerich et al., 1993).

There have been few epidemiological studies of the relation between work and shoulder tendinitis, and exposure parameters in these studies have been poorly defined. Despite this, it appears that the incidence of shoulder tendinitis is related to the performance of activities involving prolonged elevation of the arms, repeated shoulder flexion, and repetitive and forceful movements of the arms (NIOSH, 1997; Hagberg et al.,

1995). The risk of injury is particularly high when repetitive activities are executed above shoulder height, because of the load on the shoulder tendons (Hagberg et al., 1995). Shoulder tendinitis has also been described among athletes—especially baseball pitchers, swimmers, and tennis players—and professional musicians (Dupuis, 1995).

AnATomicAl review

The “shoulder” is in fact a collection of bony and ligamentous structures which depend on the interaction of multiple muscle groups to stabilise the humeral joint and perform movements. The muscles of the rotator cuff stabilise the head of the humerus in the glenoid fossa during movements of this joint and account for 50% of the shoulder’s strength during abduction and at least 80% of its strength during external rotation (Marks et al., 1994). The tendon of the long head of the biceps is involved in flexion of the forearm, coaptation of the head of the humerus, and abduction of the externally rotated arm.

General Considerations1

Shoulder Int.indd 1 02/04/08 11:33:08


2

Structure of the Shoulder Joint

The shoulder joint is formed by:

– three cartilaginous joints (the glenohumeral, acromioclavicular, and sternoclavicular)

– two sliding surfaces (the subacromial and scapulothoracic) (Kapandji, 1983)

– the compartment formed by the ligamentous junction of the acromion and the coracoid pro cess (Figure 1.1)

Guide To The Diagnosis Of Work-Related Musculoskeletal Disorders

Figure 1.1

Structure of the Shoulder Joint

Figure 1.2

Structure of Tendons

Most shoulder movements involve the simul ta neous action of the glenohumeral and scap ulo thoracic joints, associated with subacromial sliding and movement of the sternoclavicular and acro mioclavicular joints, respectively (Déziel, 1995; Murnaghan, 1988; Kapandji, 1983).

Structure of the Tendon

Tendons are composed of dense, regularly shap ed, conjunctive tissue. Because of the paral lel arrange ment of their constituent collagen fibres, they are approximately 50% as strong as cortical bone. Some tendons are entirely covered by a fibrous synovial sheath that protects them against friction with surrounding bones and ligaments. The role of tendons is to transmit muscle force in order to stabilise joints, perform movements or maintain posture (Fig ure 1.2).

Glenohumeral joint

Acromioclavicular joint

Scapulothoracic sliding surface

Sternoclavicular joint

Bone

Periosteum

Fibrous tendon sheath

Synovial membrane (outer layer)

Synovial membrane (inner layer)

Muscle

Collagen fibres

Region oftendinitis

andperitendinitis

Region oftenosynovitis

Tendon

Region of insertiontendinitis

Fibrous tendon layer

Region ofmyotendinitis

Subacromial sliding surface



3

Biomechanical Considerations

The rotator cuff and the long head of the biceps are central to the control of movements involving the glenohumeral joint. The muscles of the rotators centre the head of the humerus, allowing it to pivot in the glenoid fossa.

The rotator cuff is formed by:

– the ends of the tendons of the supraspinatus, infraspinatus, teres minor, and subscapularis muscles, all of which have their insertion on the superior humerus, just below its head (Figures 1.3a and 1.3b).

The tendon of the long head of the biceps comes into close proximity with the rotator cuff:

– Originating on the subglenoid tuberosity, it runs under the capsule of the glenohumeral joint, follows the curve of the head of the humerus, turns 90°, slides through the bicipital groove where it acquires a sheath, and finally inserts into the biceps muscle (Figure 1.4).

shoulder tendinitis

Figure 1.3b

Muscles and Tendons of the Rotator Cuff (Posterior View)

Figure 1.4

Course of the Tendon of the Long Head of the Biceps

During abduction and elevation, this group of tendons depresses the head of the humerus, sliding the greater tuberosity under the coracoacromial arch (Lacoste, 1993). This opposes the action of the del toid muscle and raises the head of the humerus against the acromial bursa. The role of the acromial bursa is to dampen various forces and facilitate the sliding of the head of the humerus under the deltoid muscle and coracoacromial arch (DupuisLeclaire, 1986).

Biceps (long head)

Supraspinatus

Infraspinatus

Teres minor

Subscapularis

Figure 1.3a

Muscles and Tendons of the Rotator Cuff (Anterior View)

Tendon of the long

head of the biceps


4

Action of the muscles of the rotator cuff and the biceps (Kendall Peterson and Kendall McCreary, 1988) (Figure 1.5)

Supraspinatus – abduction of the arm (1)Subscapularis – internal rotation of the arm (2)Infraspinatus – external rotation of the arm (3)Teres minor – external rotation of the arm (4)Long head of – flexion and abduction of the arm the biceps with the humerus ro tated (5) – also involved with elbow flexion

The rotator cuff and the tendon of the long head of the biceps are particularly important in coaptation and rotation of the head of the humerus. “Co ap tation” is the term used to describe the muscle action which brings joint surfaces closer together and main tains them in that position. Rotary force, in contrast, is responsible for

moving the arm (Williams et al., 1986). The components of the rotary and coaptation forces of the deltoid muscle are illustrated in Fig ure 1.6.


Figure 1.5

Action of the Rotator Muscles

Figure 1.6

Components of Rotary and Coaptation Forces during Shoulder Movements

D = force developed by the deltoid muscle; Fr = rotary force; Fc = coaptation force; G = weight of the arm

1

2

3

4

5

1

Fc

Fr

G

D



5

Innervation

The motor function of the rotator cuff and long head of the biceps is controlled by the nerves originating in the C4C7 roots (Box 1.1), while sensory inner vation is

shoulder tendinitis

Box 1.1

Innervation of the Rotator Cuff and Biceps Muscles

Supraspinatus Suprascapular nerve; C5, C6

Infraspinatus Suprascapular nerve; C5, C6

Teres minor Axillary nerve; C5, C6

Subscapularis Superior and inferior subscapular nerves; C5, C6

Long head of the biceps Musculocutaneous nerve; C5, C6

Source: Kendall Peterson and Kendall McCreary, 1988, Tubiana and Thomine, 1990

primarily provided by the sensory branches arising from the C4D1 roots (Kendall Peterson and Kendall McCreary, 1988) (Figure 1.7).

Figure 1.7

Dermatomes and Sensory Innervation

DerMAToMeS

SenSory InnervATIon

Anterior view Posterior view

C7

C6C5

C8

D1

C3C4D2

D2

C4 C5 C6

C7

D1C8

1

2

3

4

5

1

2

34

1. Suprascapular nerve C3,C42. Axillary nerve C5, C63. radial nerve C5, C64. Intercostobrachial and medial brachial cutaneous nerves, D1, D25. Medial antebrachial cutaneous nerve C8, D1

Reference: Netter F.H. (1995), Atlas of human anatomy, 7th edition, Ciba-Geigy Corporation, New Jersey, 314 pages.


6

physiopAThology

The most commonly advanced physiopathological mechanism underlying rotator cuff tendinitis and tenosynovitis of the long head of the biceps in volves mechanical phenomena related to the motor func tion of the shoulder and anatomical instability of the joint.

Codman, in 1934, was the first to describe damage to the rotator cuff in individuals who maintained awkward postures with the arms flexed or abducted in the course of their daily or occu pational activities. In 1983, Neer described “impinge ment syndrome”, a degenerative pathology asso ciated with friction of the supraspinatus tendon with the anterior margin of the acromion, primarily during elevation of the internally rotated arm (Leffert, 1992). This mechanical effect is exacerbated by muscular exertion, e.g. the maintenance of certain postures, which reduces local blood circulation. Jarvhölm et al. (1990) demonstrated that flexion of the arm exceeding 60° or abduction exceeding 30° disrupts circulation to the supra spinatus. Other arteriographical studies have revealed that lateral compression of the tendinous and peritendinous vascular bed can result in a virtually avascular state (Caillet, 1985). In the shoulder, this phenomenon is most commonly observed in the tendons of the supraspinatus and of the long head of the biceps (Figure 1.8).

Interruption of normal healing processes appears to be a factor in the development of inflammation following tendon damage. If muscle strain is repeated or prolonged, scar tissue will be produced around the damaged tendon, predisposing it to further damage. The stages in the development of this pathology are (Lacoste, 1993):

1. Fibrin deposition2. Continuous oedema with inflammation3. Development of granulomatous tissue4. Tissue calcification and ossification

The tissue formed as a result of this interruption of healing has different properties and not only leads to a functional imbalance between the deltoid and supraspinatus muscles but also affects peri artic ular structures.

The other tendons of the rotator cuff (infra spinatus, subscapularis, teres minor) are rarely affected on their own; damage to these structures usually occurs in cases of tendinitis of the supra spinatus or tenosynovitis of the long head of the biceps with functional decompensation (Box 1.2).


Figure 1.8

Critical Zone of the Tendons of the Supraspinatus and the Long Head

of the Biceps Subjected to Premature Wear

Coracoacromial ligamentCritical zone

of the supraspinatus

tendon

Critical zone of the tendon of the long

head of the biceps



7

shoulder tendinitis

Box 1.2

Contributory Factors for Tendinitis of the Rotator Cuff and Tenosynovitis of the Long Head of the Biceps

• Anatomical

– Presence of a critical avascular zone (Codman zone) approximately 1 cm from the insertion of the tendons, especially the supraspinatus

• Mechanical

– Compression-related stress when the head of the humerus is elevated against the coraco-acromial arch

– Inflammation as a result of repeated or prolonged stress

– Traction associated with throwing motions with the arm abducted or elevated

• Vascular

– Disruption of the circulation caused by arm flexion exceeding 30°

– Compression of the tendinous and peritendinous vascular bed Source: Hagberg et al., 1995; Dupuis-Leclaire, 1986






DISORDERS3Work-related musculoskeletal injuries are one of the most common occupational

health problems for which physicians are consulted. There is solid scientific evidence thatthese injuries may be occupational in origin.

This guide was designed to help physicians interpret the results of a medicalexamination. By combining the standard clinical assessment procedure with guidelinesconcerning the identification of etiological factors, it helps physicians identify the causeof injury.

AUTHORS

Louis Patry holds a degree in medicine from Laval University anda diploma in ergonomics from the Conservatoire National des Artset Metiers de Paris (CNAM). He is a specialist in occupational medi-cine, an associate member of the Royal College of Physicians andSurgeons of Canada, a professor in McGill University’s Departmentof Epidemiology and Biostatistics and Occupational Health, and con-sulting physician to the Direction de la santé publique (Public HealthDepartment), first in Québec City and currently at the Montréal-Centre board.

Michel Rossignol holds degrees in biochemistry and medicinefrom the University of Sherbrooke, in epidemiology and communityhealth from McGill University, and in occupational medicine fromJohn Hopkins University. He is a professor in McGill University’sDepartment of Epidemiology and Biostatistics and OccupationalHealth, co-director of the Centre for Clinical Epidemiology of theJewish General Hospital of Montréal, and physician-epidemiologistat the Montréal-Centre board of the Direction de la santé publique(Public Health Department).

Marie-Jeanne Costa holds a nursing degree from the Institutd’études paramédicales de Liège and a degree in ergonomics fromthe École Pratique des Hautes Études de Paris. She is an ergonomicsconsultant and has collaborated on several studies of CTDs. She isparticularly interested in the development of participatory ergonom-ics, specifically in the problem-resolution and diagnostic processes.

Martine Baillargeon holds a degree in medicine from theUniversité de Montréal. She is a plastic surgeon and associate mem-ber of the Royal College of Physicians and Surgeons of Canada.After years of practising surgery she is now consulting physician,mainly in the field of musculoskeletal injuries affecting the upperlimb, at the Montréal-Centre board of the Direction de la santépublique (Public Health Board).

ShoulderTendinitis

ShoulderTendinitis

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Front CoverPrefaceIntroductionTable of ContentsList of FiguresList of TablesList of BoxesGeneral ConsiderationsTerminologyEpidemiologyAnatomical ReviewStructure of the Shoulder JointStructure of the TendonBiomechanical ConsiderationsInnervation

Physiopathology

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