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Bones and Joints

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Bone and cartilage are part of the specialized connective tissues that make up the skeletal system. Bone is a living tissue that replaces itself continuously. The hardness of bone is well suited to the task of providing mechanical support function, and the elasticity of cartilage, to the ability of joints to move. Both cartilage and bone consist of specialized cells that produce and regulate a matrix of material outside the cells. The matrix is abundant in collagens, proteoglycans and non-collagenous proteins. Minerals are present in bone matrix as well.

The external part of bone is called the cortex and is compact bone. The more spongy inner part (trabecular bone) is filled with blood-forming (haematopoietic) bone marrow. The inner and outer parts of the bone have different metabolic turnover rates, with important consequences for late life osteoporosis. Trabecular bone regenerates itself at a greater rate than compact bone, which is why osteoporosis is first seen in the vertebral bodies of the spine, which have large trabecular parts.

Bone in the skull and other selected sites forms directly by bone formation (intramembranous ossification) without passing through a cartilage intermediate phase. The long bones of the limbs develop from cartilage through a process known as endochondral ossification. This process is what leads to the normal growth of long bones, to the repair of fractures and, in late adult life, to the unique formation of new bone in a joint which has become osteoarthritic.

The osteoblast is a type of bone cell that is responsible for synthesis of the matrix components in bone: the distinct collagen (type I) and proteoglycans. Osteoblasts also synthesize other non-collagenous proteins of bone. Some of these proteins can be measured in serum to determine the rate of bone turnover.

The other distinct bone cell is called the osteoclast. The osteoclast is responsible for resorption of bone. Under normal circumstances, old bone tissue is resorbed while new bone tissue is generated. Bone is resorbed by production of enzymes that dissolve proteins. Bone turnover is called remodelling and is normally a balanced and coordinated process of resorption and formation. Remodelling is influenced by body hormones and by local growth factors.

Movable (diarthrodial) joints are formed where two bones fit together. Joint surfaces are designed for weight bearing, and to accommodate a range of motion. The joint is enclosed by a fibrous capsule, whose inner surface is a synovial membrane, which secretes synovial fluid. The joint surface is made of hyaline cartilage, beneath which is a backing of hard (subchondral) bone. Within the joint, ligaments, tendons and fibrocartilaginous structures (menisci in certain joints, such as the knee), provide stability and a close fit between joint surfaces. The specialized cells of these joint components synthesize and maintain the matrix macromolecules whose interactions are responsible for maintaining the tensile strength of ligaments and tendons, the loose connective tissue that supports the blood vessels and cellular elements of the synovial membrane, the viscous synovial fluid, the elasticity of hyaline cartilage, and the rigid strength of subchondral bone. These joint components are interdependent, and their relationships are shown in table 1.

Table 1. Structure-function relationships and inter-dependence of joint components.




Ligaments and tendons

Dense, fibrous, connective tissue

Prevents over-extension of joints, provides stability and strength

Synovial membrane

Areolar, vascular and cellular

Secretes synovial fluid, dissolves (phagocytoses) particulate material in synovial fluid

Synovial fluid

Viscous fluid

Provides nutrients for cartilage injoints, lubricates cartilage during joint motion


Firm hyaline cartilage

Constitutes the joint surface, bears weight, responds elastically to compression


Calcified cartilage

Separates joint cartilage from underlying bone

Subchondral bone

Hard bone with marrow spaces

Provides backing for joint surface; marrow cavity provides nutrients to base of cartilage and is thesource of cells with potential fornew bone formation

Source: Hamerman and Taylor 1993.

Selected Diseases of Bones and Joints

Osteopenia is the general term used to describe reduced bone substance detected on x rays. Often asymptomatic in early stages, it may eventually manifest itself as weakening of bones. Most of the conditions listed below induce osteopenia, although the mechanisms by which this occurs differ. For example, excessive parathyroid hormone enhances bone resorption, while calcium and phosphate deficiency, which can arise from multiple causes and is often due to inadequate vitamin D, results in deficient mineralization. As people age, there is an imbalance between formation and resorption of bone. In women around the age of menopause, resorption often predominates, a condition called type I osteoporosis. In advanced age, resorption can again dominate and lead to type II osteoporosis. Type I osteoporosis usually affects vertebral bone loss and collapse, while hip fracture predominates in type II.

Osteoarthritis (OA) is the principal chronic disorder of certain movable joints, and its incidence increases with age. By age 80, almost all people have enlarged joints on the fingers (Heberden’s nodes). This is usually of very limited clinical significance. The principal weight-bearing joints which are subject to osteoarthritis are the hip, knee, feet and facets of the spine. The shoulder, while it is not weight bearing, may also suffer from a variety of arthritic changes, including rotator cuff tear, subluxation of the humeral head and an effusion high in proteolytic enzymes—a clinical picture often called “Milwaukee Shoulder” and associated with substantial pain and limitation of motion. The main change in OA is primarily one of degradation of cartilage, but new bone formation called osteophytes is usually seen on x rays.



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Musculoskeletal System References

Agency for Health Care Policy and Research (AHCPR). 1994. Acute low-back problems in adults. Clinical Pratice Guidelines 14. Washington, DC: AHCPR.

Allander, E. 1974. Prevalence, incidence and remission rates of some common rheumatic diseases or syndromes. Scand J Rheumatol 3:145-153.

American Academy of Orthopaedic Surgeons. 1988. Joint Motion. New York: Churchill Livingstone.
Anderson, JAD. 1988. Arthrosis and its relation to work. Scand J Work Environ Health 10:429-433.

Anderson, JJ and DT Felson. 1988. Factors associated with osteoarthritis of the knee in the first National Health and Nutrition Survey (HANES 1): Evidence for an association with overweight, race and physical demands of work. Am J Epidemiol 128:179-189.

Angelides, AC. 1982. Ganglions of the hand and wrist. In Operative Hand Surgery, edited by DP Green. New York: Churchill Livingstone.

Armstrong, TJ, WA Castelli, G Evans, and R Diaz-Perez. 1984. Some histological changes in carpal tunnel contents and their biomechanical implications. J Occup Med 26(3):197-201.

Armstrong, TJ, P Buckle, L Fine, M Hagberg, B Jonsson, A Kilbom, I Kuorinka, B Silverstein, B Sjøgaard, and E Viikari-Juntura. 1993. A conceptual model for work-related neck and upper-limb musculoskeletal disorders. Scand J Work Environ Health 19:73-84.

Arnett, FC, SM Edworthy, DA Bloch, DJ McShane, JF Fries, NS Cooper, LA Healey, SR Kaplan, MH Liang, HS Luthra, TAJ Medsger, DM Mitchell, DH Neustadt, RS Pinals, JG Schaller, JT Sharp, RL Wilder, and GG Hunder. 1988. The American Rheumatism Association 1987 revised criteria for the classification of rheumatoid arthritis. Arthritis Rheum 31:315-324.

Aronsson, G, U Bergkvist, and S Almers. 1992. Work Oganization and Musculoskeletal Disorders in VDU-Work (Swedish with Summary in English). Solna: National Institute of Occupational Health.
Axmacher, B and H Lindberg. 1993. Coxarthrosis in farmers. Clin Orthop 287:82-86.

Bergenudd, H, F Lindgärde, and B Nilsson. 1989. Prevalence and coincidence of degenerative changes of the hands and feet in middle age and their relationship to occupational work load, intelligence, and social background. Clin Orthop 239:306-310.

Brinckmann, P and MH Pope. 1990. Effects of repeat-ed loads and vibration. In The Lumbar Spine, edited by J Weinstein and SW Weisel. Philadelphia: WB Saunders.

Calin, A, J Elswood, S Rigg, and SM Skevington. 1988. Ankylosing spondylitis - an analytical review of 1500 patients: The changing pattern of disease. J Rheumatol 15:1234-1238.

Chaffin, D and GBJ Andersson. 1991. Occupational Bio-mechanics. New York: Wiley.

Daniel, RK and WC Breidenbach. 1982. Tendon: structure, organization and healing. Chap. 14 in The Musculoskeletal System: Embryology, Biochemistry and Physiology, edited by RL Cruess. New York: Churchill Livingstone.

Dougados, M, S van der Linden, R Juhlin, B Huitfeldt, B Amor, A Calin, A Cats, B Dijkmans, I Olivieri, G Pasero, E Veys, and H Zeidler. 1991. The European Spondylarthropathy Study Group preliminary criteria for the clasification of spondylarthropathy. Arthritis Rheum 34:1218-1227.

Edwards, RHT. 1988. Hypotheses of peripheral and central mechanisms underlying occupational muscle pain and injury. Eur J Appl Physiol 57(3):275-281.

Felson, DT. 1990. The epidemiology of knee osteoarthritis: Results from the Framingham Osteoarthritis Study. Sem Arthrit Rheumat 20:42-50.

Felson, DT, JJ Anderson, A Naimark, AM Walker, and RF Meenan. 1988. Obesity and knee osteoarthritis: The Framingham study. Ann Intern Med 109:18-24.

Fung, YB. 1972. Stress-strain history relations of soft tissues in simple elongation. Chap. 7 in Biomechanics: Its Foundations and Objectives, edited by YC Fung, N Perrone, and M Anliker. Englewood Cliffs, NJ: Prentice Hall.

Gelberman, R, V Goldberg, K An, and A Banes. 1987. Tendon. Chap. 1 in Injury and Repair of the Musculoskeletal Soft Tissue, edited by SL Woo and JA Buckwalter. Park Ridge, Ill: American Academy of Orthopaedic Surgeons.

Gemne, G and H Saraste. 1987. Bone and joint pathology in workers using hand-held vibrating tools. Scand J Work Environ Health 13:290-300.

Goldberg, DL. 1987. Fibromyalgia syndrome. An emerging but controversial condition. JAMA 257:2782-2787.

Goldstein, SA, TJ Armstrong, DB Chaffin, and LS Matthews. 1987. Analysis of cumulative strain in tendons and tendon sheaths. J Biomech 20(1):1-6.

Gran, JT and G Husby. 1993. The epidemiology of ankylosing spondylitis. Sem Arthrit Rheumat 22:319-334.

Guidelines and audit measures for the specialist supervision of patients with rheumatoid arthritis. Report of a Joint Working Group of the British Society for Rheumatology and the Research Unit of the Royal College of Physicians. 1992. J Royal Coll Phys 26:76-82.

Hagberg, M. 1982. Local shoulder muscular strain symptoms and disorders. J Hum Ergol 11:99-108.
Hagberg, M and DH Wegman. 1987. Prevalence rates and odds ratios of shoulder neck diseases in different occupational groups. Brit J Ind Med 44:602-610.

Hagberg, M, H Hendrick, B Silverstein, MJ Smith, R Well and P Carayon. 1995. Work Related Musculoskeletal Disorders (WMSDs): A Reference Book for Prevention, edited by I Kuorinka, and L Forcier. London: Taylor & Francis.

Hägg, GM, J Suurküla, and Å Kilbom. 1990. Predictors for Work-Related Shoulder-Neck Disorders (Swedish with Summary in English). Solna: National Institute of Occupational Health.

Halpern, M. 1992. Prevention of low back pain: Basic ergonomics in the workplace and the clinic. Bailliere’s Clin Rheum 6:705-730.

Hamerman, D and S Taylor. 1993. Humoral factors in the pathogenesis of osteoarthritis. In Humoral Factors in the Regulation of Tissue Growth, edited by PP Foá. New York: Springer.

Hannan, MT, DT Felson, JJ Anderson, A Naimark, and WB Kannel. 1990. Estrogen use and radiographic osteoarthritis of the knee in women. Arthritis Rheum 33:525-532.

Hansen, SM. 1993. Arbejdsmiljø Og Samfundsøkonomi -En Metode Til Konsekvensbeskrivning. Nord: Nordisk Ministerråd.

Hansen, SM and PL Jensen. 1993. Arbejdsmiljø Og Samfundsøkonomi -Regneark Og Dataunderlag. Nord: Nordisk Ministerråd. (Nordiske Seminar - og Arbejdsrapporter 1993:556.)

Hansson, JE. 1987. Förararbetsplatser [Work stations for driving, in Swedish]. In Människan I Arbete, edited by N Lundgren, G Luthman, and K Elgstrand. Stockholm:Almqvist & Wiksell.

Heliövaara, M, M Mäkelä, and K Sievers. 1993. Musculoskeletal Diseases in Finland (in Finnish). Helsinki: Kansaneläkelaitoksen julkaisuja AL.

Järvholm U, G Palmerud, J Styf, P Herberts, R Kadefors. 1988. Intramuscular pressure in the supraspinatus muscle. J Orthop Res 6:230-238.

Jupiter, JB and HE Kleinert. 1988. Vascular injuries of the upper extremity. In The Hand, edited by R Tubiana. Philadelphia: WB Saunders.

Kärkkäinen, A. 1985. Osteoarthritis of the Hand in the Finnish Population Aged 30 Years and Over (in Finnish with an English summary). Finland: Publications of the Social Insurance Institution.

Kivi, P. 1982. The etiology and conservative treatment of humeral epicondylitis. Scand J Rehabil Med 15:37-41.

Kivimäki, J. 1992. Occupationally related ultrasonic findings in carpet and floor layers knees. Scand J Work Environ Health 18:400-402.

Kivimäki, J, H Riihimäki and K Hänninen. 1992. Knee disorders in carpet and floor layers and painters. Scand J Work Environ Health 18:310-316.

Kohatsu, ND and D Schurman. 1990. Risk factors for the development of osteoarthrosis of the knee. Clin Orthop 261:242-246.

Kuorinka, I, B Jonsson, Å Kilbom, H Vinterberg, F Biering-Sørensen, G Andersson, and K Jørgensen. 1987. Standardised Nordic questionnaires for the analysis of musculoskeletal symptoms. Appl Ergon 18:233-237.

Kurppa, K, E Viikari-Juntura, E Kuosma, M Huus-konen, and P Kivi. 1991. Incidence of tenosynovitis or peritendinitis and epicondylitis in a meat-processing factory. Scand J Work Environ Health 17:32-37.

Leadbetter, WB. 1989. Clinical staging concepts in sports trauma. Chap. 39 in Sports-Induced Inflammation: Clinical and Basic Science Concepts, edited by WB Leadbetter, JA Buckwalter, and SL Gordon. Park Ridge, Ill: American Academy of Orthopaedic Surgeons.

Lindberg, H and F Montgomery. 1987. Heavy labor and the occurence of gonarthrosis. Clin Orthop 214:235-236.

Liss, GM and S Stock. 1996. Can Dupuytren’s contracture be work-related?: Review of the evidence. Am J Ind Med 29:521-532.

Louis, DS. 1992. The carpal tunnel syndrome in the work place. Chap. 12 in Occupational Disorders of the Upper Extremity, edited by LH Millender, DS Louis, and BP Simmons. New York: Churchill Livingstone.

Lundborg, G. 1988. Nerve Injury and Repair. Edinburgh: Churchill Livingstone.
Manz, A, and W Rausch. 1965. Zur Pathogenese und Begutachtung der Epicondylitis humeri. Münch Med Wochenshcr 29:1406-1413.

Marsden, CD and MP Sheehy. 1990. Writer’s cramp. Trends Neurosci 13:148-153.

Mense, S. 1993. Peripheral mechanisms of muscle nociception and local muscle pain. J Musculoskel Pain 1(1):133-170.

Moore, JS. 1992. Function, structure, and responses of the muscle-tendon unit. Occup Med: State Art Rev 7(4):713-740.

Mubarak, SJ. 1981. Exertional compartment syndromes. In Compartment Syndromes and Volkmann’s Contracture, edited by SJ Mubarak and AR Hargens. Philadelphia: WB Saunders.

Nachemson, A. 1992. Lumbar mechanics as revealed by lumbar intradiscal pressure measurements. In The Lumbar Spine and Back Pain, edited by MIV Jayson. Edinburgh: Churchill Livingstone.

Obolenskaja, AJ, and Goljanitzki, JA. 1927. Die seröse Tendovaginitis in der Klinik und im Experiment. Dtsch Z Chir 201:388-399.

Partridge, REH and JJR Duthie. 1968. Rheumatism in dockers and civil servants: A comparison of heavy manual and sedentary workers. Ann Rheum Dis 27:559-568.

Rafusson V, OA Steingrímsdóttir, MH Olafsson and T Sveinsdóttir. 1989. Muskuloskeletala besvär bland islänningar. Nord Med 104: 1070.

Roberts, S. 1990. Sampling of the intervertebral disc. In Methods in Cartilage Research, edited by A Maroudas and K Kuettner. London: Academic Press.

Rydevik, BL and S Holm. 1992. Pathophysiology of the intervertebral disc and adjacent structures. In The Spine, edited by RH Rothman and FA Simeone. Philadelphia: WB Saunders.

Schüldt, K. 1988. On neck muscle activity and load reduction in sitting postures. Ph.D. thesis, Karolinska Institute. Stockholm.

Schüldt, K, J Ekholm, J Toomingas, K Harms-Ringdahl, M Köster, and Stockholm MUSIC Study Group 1. 1993. Association between endurance/exertion in neck extensors and reported neck disorders (In Swedish). In Stockholm Investigation 1, edited by M Hagberg and C Hogstedt. Stockholm:MUSIC Books.

Silverstein, BA, LJ Fine, and J Armstrong. 1986. Hand wrist cumulative trauma disorders in industry. Brit J Ind Med 43:779-784.

Sjøgaard, G. 1990. Exercise-induced muscle fatigue: The significance of potassium. Acta Physiol Scand 140 Suppl. 593:1-64.

Sjøgaard, G, OM Sejersted, J Winkel, J Smolander, K Jørgensen, and R Westgaard. 1995. Exposure assessment and mechanisms of pathogenesis in work-related musculoskeletal disorders: Significant aspects in the documentation of risk factors. In Work and Health. Scientific Basis of Progress in the Working Environment, edited by O Svane and C Johansen. Luxembourg: European Commission, Directorate-General V.

Spitzer, WO, FE LeBlanc, M Dupuis, et al. 1987. Scientific approach to the assessment and management of activity-related spinal disorders. Spine 12(7S).

Tidswell, M. 1992. Cash’s Textbook of Orthopaedics and Rheumatology for Physiotherapists. Europa: Mosby.

Thompson, AR, LW Plewes, and EG Shaw. 1951. Peritendinitis crepitans and simple tenosynovitis: A clinical study of 544 cases in industry. Brit J Ind Med 8:150-160.

Urban, JPG and S Roberts. 1994. Chemistry of the intervertebral disc in relation to functional requirements. In Grieve’s Modern Manual Therapy, edited by JD Boyling and N Palastanga. Edinburgh: Churchill Livingstone.

Viikari-Juntura, E. 1984. Tenosynovitis, peritendinitis and the tennis elbow syndrome. Scand J Work Environ Health 10:443-449.

Vingård, E, L Alfredsson, I Goldie, and C Hogstedt. 1991. Occupation and osteoarthrosis of the hip and knee. Int J Epidemiol 20:1025-1031.

Vingård, E, L Alfredsson, I Goldie, and C Hogstedt. 1993. Sports and osteoarthrosis of the hip. Am J Sports Med 21:195-200.

Waters, TR, V Putz-Anderson, A Garg, and LJ Fine. 1993. Revised NIOSH equation for design and evaluation of manual lifting tasks. Ergonomics 36:739-776.

Wickström, G, K Hänninen, T Mattsson, T Niskanen, H Riihimäki, P Waris, and A Zitting. 1983. Knee degeneration in concrete reinforcement workers. Brit J Ind Med 40:216-219.

Wolfe, F. 1986. The clinical syndrome of fibrositis. Am J Med 81 Suppl. 3A:7-14.

Wolfe, F, HA Smythe, MB Yunus, RM Bennett, C Bombardier, DL Goldenberg, P Tugwell, SM Campbell, M Abeles, P Clark, AG Fam, SJ Farber, JJ Fiechtner, CM Franklin, RA Gatter, D Hamaty, J Lessard, AS Lichtbroun, AT Masi, GA McCain, WJ Reynolds, TJ Romano, IJ Russell, and RP Sheon. 1990. The American College of Rheumatology criteria for the classification of fibromyalgia. Report of the multicenter criteria committee. Arthritis Rheum 33:160-172.

Yunus, MB. 1993. Research in fibromyalgia and myofascial pain syndromes: Current status, problems and future directions. J Musculoskel Pain 1(1):23-41.