1. Musculoskeletal System PART-1. 120-08-2014

2. The skeletal system is vital during life. Essential role in mineral homeostasis, houses the hematopoietic elements, provides mechanical support for movement, protects viscera, and determines body size and shape. Bones are largely made up of an organic matrix (osteoid) and the mineral calcium hydroxyapatite, which gives the bones strength and hardness. Stony hard structure, bone is a dynamic tissue that is continuously resorbed, renewed, and remodelled. 220-08-2014 3. Parts of a long bones: Diaphysis (shaft), physis (growth plate), Epiphysis (ends of bone, partially covered by articular cartilage), Metaphysis (junction of diaphysis and epiphysis, most common site of primary bone tumors) Cross section: Periosteam, cortex (composed of cortical bone or compact bone), Medullary space (composed of cancellous or spongy bone) 320-08-2014 4. 420-08-2014 5. Normal histology Bone: mineralized osteoid; either lamellar bone or woven bone. Lamellar bone: layered bone with concentric parallel lamellae; gradually replaces woven bone; normal type of bone found in adult skeleton; stronger than woven bone 520-08-2014 6. Osteoblasts: arise from marrow mesenchymal cells; when active, are plump and present on bone surface; eventually are encased within the collagen they produce. Osteoblasts control osteoclast activity via parathyroid hormone. 620-08-2014 7. 720-08-2014 8. A, Active osteoblasts synthesizing bone matrix. The surrounding spindle cells represent osteoprogenitor cells. B, Two osteoclasts resorbing bone. 820-08-2014 9. 920-08-2014 10. Osteomyelitis Avascular necrosis, osteonecrosis Skeletal dysplasias , achondroplasia, osteogenesis imperfecta, osteopetrosis, Metabolic and endocrine diseases Osteoporosis Osteitis fibrosa cystica 1020-08-2014 11. Renal osteodystropy Skeletal fluorosis Paget's disease of bone, osteitis deformans Tumour like lesions of bone. 1120-08-2014 12. 1220-08-2014 13. OSTEOMYELITIS: Denotes inflammation of bones and marrow and the common use of the term virtually always implies infection. May be a complication of any systemic infection but frequently manifests as a primary solitary focus of disease. All types of organisms ,including viruses, parasites, fungi and bacteria can produce osteomyelitis, but infections caused by certain pyogenic bacteria and mycobacteria are the most common. 1320-08-2014 14. 1420-08-2014 15. 1520-08-2014 16. 1620-08-2014 17. 1720-08-2014 18. 1820-08-2014 19. Resected femur in a person with draining osteomyelitis. The drainage tract in the sub periosteal shell of viable new bone (involucrum) reveals the inner native necrotic cortex (sequestrum). 1920-08-2014 20. PYOGENIC OSTEOMYELITIS: is almost always caused by bacteria. 1. Hematogenous spread. 2. Extension from a contiguous site. 3. Direct implantation. 2020-08-2014 21. E.coli, Klebsiella and Pseudomonas are more frequently isolated from patients with genitourinary tract infections or with intravenous drug abusers. Mixed bacterial infections can be seen in the setting of direct spread during surgery or open fractures. Salmonella infections for unknown reasons common in sickle cell patients. 2120-08-2014 22. In 50% of the cases no organisms can be isolated. 2220-08-2014 23. Sites of involvement: Influenced by the vascular circulation, which varies with age. Neonates: the metaphysical vessels penetrate the growth plate, resulting in frequent infection of the metaphysis, epiphysis or both. In children: metaphysical. Adults: epiphyses and subchondral regions. 2320-08-2014 24. Stages : Acute Sub acute Chronic , On clinical duration of disease SEQUENCE OF INFECTION: Once localized in bone, the bacteria proliferate and induce an acute inflammatory reactions and causes cell death. 2420-08-2014 25. Necrosis of the bone within first 48hrs. Spread of bacteria and inflammation within the shaft of the bone and may percolate through the haversian systems to reach the periosteum. In children ,the periosteum is loosely attached to the cortex; therefore sizable sub periosteal abscess formation occurs. 2520-08-2014 26. Further ischemia and bone necrosis occurs. 2620-08-2014 27. Dead pieces of bone are known as the sequestrum. Rupture of the periosteumsoft tissue abscess formationdraining sinuses. In infants epiphyseal infection may spread to the adjacent joint and causes septic or suppurative arthritis.; may lead to permanent disability. 2720-08-2014 28. After the first week chronic inflammatory cells become more numerous with the release of cytokines and deposition of new bone formation at the periphery. New bone may be deposited as a sleeve of living tissue known as the Involucrum. 2820-08-2014 29. Brodies abscess: Small intraosseus abscess that frequently involves the cortex and is walled off reactive bone. Sclerosing osteomyelitis of Garre typically develops in the jaw. 2920-08-2014 30. Clinical Course: Fever ,chills, malaise, marked to intense throbbing pain over the affected region. Diagnosis; Sign/symptoms. X-ray Blood cultures Biopsy.-HISTOPATHOLOGY. 3020-08-2014 31. Complications: Acute bacterial arthritis. Pathologic fracture. Secondary amyloidosis Endocarditis Septicaemia. Squamous cell carcinoma. Rarely sarcoma in the affected bone 3120-08-2014 32. Tuberculous osteomyelitis: Routes of entry; Usually blood borne and originate from a focus of active visceral disease. Direct extension (e.g. from a pulmonary focus into a rib or from tracheobronchial nodes into adjacent vertebrae) or spread via draining lymphatics. 3220-08-2014 33. In patients with AIDS frequently multifocal. Pott disease is the involvement of Spines. Thoracic and lumber vertebrae followed by the knees and hips are the most common sites of skeletal involvement. The infection breaks through the invertebral discs and extends into the soft tissues forming abscesses. 3320-08-2014 34. Clinical features and complications: Pain Fever , Weight loss May form an inguinal mass which represents a cold fluctuant psoas abscess. Bone destruction. Tuberculous arthritis. Sinus tract formation Amyloidosis. 3420-08-2014 35. Osteonecrosis Fracture dislocation Corticosteroids administration Radiation therapy Sickle cell disease. 3520-08-2014 36. 3620-08-2014 37. Femoral head with a subchondral, wedge- shaped pale yellow area of osteonecrosis. The space between the overlying articular cartilage and bone is caused by trabecular compression fractures without repair. 3720-08-2014 38. Osteogenesis imperfecta Autosomal dominant disorder of synthesis of type 1 collagen that constitutes to 90-95% of bone matrix. Sclera,eyes,joints,ligaments, teeth, skin. Too little bone. Type-1. 2, 3, 4. 3820-08-2014 39. 3920-08-2014 40. Skeletal radiogram of a fetus with lethal type II osteogenesis imperfecta. Note the numerous fractures of virtually all bones, resulting in accordion-like shortening of the limbs. 4020-08-2014 41. Osteopetrosis Marble bone disease. Autosomal disorder, characterised by increased skeletal mass or osteosclerosis caused by hereditary defect in osteoclast dysfunction. 4120-08-2014 42. Failure of normal osteoclast dysfunction of bone resorption coupled with continued bone formation and endochondral ossification results in net overgrowth of calcified dense bone. Too much bone 4220-08-2014 43. 4320-08-2014 44. Radiogram of the upper extremity in an individual with osteopetrosis. The bones are diffusely sclerotic, and the distal metaphyses of the ulna and radius are poorly formed (Erlenmeyer flask deformity). 4420-08-2014 45. 4520-08-2014 46. Section of proximal tibial diaphysis from a fetus with osteopetrosis. The cortex (1) is present, but the medullary cavity (2) is filled with primary spongiosa, which replaces the hematopoietic elements. 4620-08-2014 47. Metabolic and Endocrine bone diseases. Osteoporosis Osteomalacia and rickets Scurvy. Hyper parathyroidism Thyroid dysfunction Renal osteodystropy Skeletal fluorosis. 4720-08-2014 48. OSTEOPOROSIS. COMMOM CLINICAL SYNDROME, involving multiple bones in which quantitative reduction of bone tissue mass but the bone tissue mass is otherwise normal. Elderly, post menopausal women. Backache . Radiologicaly 30% of bone mass. 4820-08-2014 49. 4920-08-2014 50. Pathophysiology of postmenopausal and senile osteoporosis . 5020-08-2014 51. 5120-08-2014 52. Osteoporotic vertebral body (right) shortened by compression fractures compared with a normal vertebral body. Note that the osteoporotic vertebra has a characteristic loss of horizontal trabeculae and thickened vertical trabeculae. 5220-08-2014 53. OSTEOPOROSIS Many diseases and disorders have been associated with osteoporosis In general, immobilization causes bone loss (following the 'use it or lose it' rule). Hypo gonadal states can cause secondary osteoporosis These include Turner syndrome, Klinefelter syndrome, Kallmann syndrome, anorexia nervosa, hypothalamic amenorrhea 5320-08-2014 54. OSTEOPOROSIS A bilateral oophorectomy (surgical removal of the ovaries) or a premature ovarian failure Endocrine disorders that can induce bone loss include Endocrine disorders that can induce bone loss include Cushing's syndrome, hyperparathyroidism, thyrotoxicosis, hypothyroidism, diabetes mellitus type 1 and type 2. 5420-08-2014 55. 5520-08-2014 56. OSTEOPOROSIS Is a term that denotes increased porosity of the skeleton resulting from reduction in the bone mass. It may be localized disuse osteoporosis of a limb. or may involve the entire skeleton, as a metabolic bone disease. 5620-08-2014 57. OSTEOPOROSIS Primary Secondary PRIMARY: Post menopausal Senile 5720-08-2014 58. OSTEOPOROSIS Secondary: immobilization, Endocrine Disorders chronic anemia, medications. 5820-08-2014 59. OSTEOPOROSIS 5920-08-2014 60. 6020-08-2014 61. OSTEOPOROSIS 6120-08-2014 62. Vertebral bone with osteoporosis demonstrates a compressed 6220-08-2014 63. OSTEOPOROSIS Pathophysiology: AGING replicative activity of the osteoprogenitorcells synthetic activity of the osteoblasts. activity of the matrix bound growth factors. 6320-08-2014 64. OSTEOPOROSIS Menopause: serum estrogen IL-1,IL-6 levels osteoclast activity Genetic factors Nutritional effects 6420-08-2014 65. OSTEOPOROSIS The two main biochemical markers for bone formation are serum alkaline phosphatase and serum osteocalcin. Markers for bone resorbtion include urinary calcium and urinary hydroxyproline 6520-08-2014 66. OSTEOPOROSIS Prevention Strategies The best long-term approach to osteoporosis is prevention. Children and young adults, particularly women, with a good diet (with enough calcium and vitamin D) and get plenty of exercise, will build up and maintain bone mass. This will provide a good reserve against bone loss later in life. Exercise places stress on bones that builds up bone mass 6620-08-2014 67. Osteitis fibrosa cystica Skeletal manifestation of hyperparathyroidism. Hyper calcaemia. Brown tumour or reparative gaint cell granuloma of hyperparathyroidism. Demineralization, bone resorption. 6720-08-2014 68. Hyperparathyroidism with osteoclasts boring into the center of the trabeculum (dissecting osteitis). 6820-08-2014 69. 6920-08-2014 70. Resected rib, harboring an expansile brown tumour adjacent to the costal cartilage. 7020-08-2014 71. 7120-08-2014 72. A, Recent fracture of the fibula. B, Marked callus formation 6 weeks later. 7220-08-2014 73. Metabolic bone disease. Renal osteodystropy Skeletal abnormalities in cases of chronic renal failure, Patients treated by dialysis. 7320-08-2014 74. 7420-08-2014 75. Skeletal fluorosis. High sodium fluoride content in soil and water. Endemic fluorosis: Panjab , Andhra Pradesh. Nonendemic fluorosis: Aluminium,megesium,superphosphate. 7520-08-2014 76. JAMES PAGET IN 1877 Pagets diseases of bone or osteitis deformans. Osteolytic and osteosclerotic disease of bone of uncertain aetiology involving one bone or more bones. Age 50 yrs. 7620-08-2014 77. 7720-08-2014 78. Diagrammatic representation of Paget disease of bone demonstrating the three phases in the evolution of the disease. 7820-08-2014 79. 7920-08-2014 80. Mosaic pattern of lamellar bone is pathognomonic of Paget disease. 8020-08-2014 81. 8120-08-2014 82. Severe Paget disease. The tibia is bowed and the affected portion is enlarged, sclerotic, and exhibits irregular thickening of both the cortical and cancellous bone. 8220-08-2014 83. 8320-08-2014 84. Fibrous dysplasia Fibrous dysplasia is a common benign fibro-osseous lesion, which occurs sporadically during the period of skeletal growth (ages 10 to25). It is a hamartoma and is characterized by the intramedullary location. There are two forms of the disease: monostotic (80% of cases) and polyostotic. Polyostotic involvement may be a part of McCune-Albright syndrome (fibrous dysplasia, patchy cutaneous pigmentation, and precocious puberty), or Mazabraud's syndrome (fibrous dysplastic lesions in close proximity to soft tissue 8420-08-2014 85. Most common locations include the long bones (femur, tibia andhumerus), the ribs, cranio-facial bones and pelvis. In the long bones, the lesion is found in the metaphysis or diaphysis. The hallmark of fibrous dysplasia is inability of tissue at the affected site to produce mature lamellar bone 8520-08-2014 86. Fibrous dysplasia Typical Clinical Picture: A 22-year-old female was seen in consultation for a lesion in the proximal femur. She complained of chronic mild to moderate pain in her right hip and was walking with a noticeable limp. Physical examination revealed hip deformity and minimal limb length discrepancy. There were no other abnormal findings. 8620-08-2014 87. 8720-08-2014 88. A very characteristic feature is "ground glass" (homogenous) density. Remember that when this disorder involves the long bone, it commonly produces what is called "long lesion in the long bone" with Three key features: lucency, sclerotic rim and cortical expansion. 8820-08-2014 89. 8920-08-2014 90. Three characteristic histologic features of this entity: a) thin, wavy spicules of woven bone ("chinese characters"); b) lack of osteoblastic rimming or osteoclastic activity; c) moderately cellular bland fibrous background. In children, stromal mitoses may be frequent, 1 to 5 per hpf 9020-08-2014 91. Non-Ossifying Fibroma (NOF) OR (Fibrous cortical defect, or Metaphysical cortical defect) 9120-08-2014 92. NOF is a common, non-neoplastic, self-healing lesion occurring in skeletally immature individuals, usually between the ages of 5 and 20 years. Small lesions are usually incidental radiological findings. The larger lesions occupying more than a half of the bone diameter may present with a pathologic fracture. l Location. In most cases, NOF presents as a solitary lesion in the metaphysis or meta-diaphysis of the long bone at the knee (distal femur, proximal tibia or fibula), distal tibia and proximal humerus. 9220-08-2014 93. Typical Clinical Presentation: An incidental finding of a bone lesion in the distal tibial meta-diaphysis of an 13-year-old male. The lesion was totally asymptomatic. l As always, pay attention to the patient's age. The fact that the lesion did not produce symptoms and was found incidentally suggests benignancy. 9320-08-2014 94. 9420-08-2014 95. Plain radiograph shows a sharply demarcated, lucent, loculated, metadiaphyseal lesion surrounded by a rim of sclerotic bone. Note the eccentric location along the long axis of the bone. 9520-08-2014 96. 9620-08-2014 97. Solitary Bone Cyst (SBC) Typical Clinical Presentation: A 12-year-old boy presented with a short history of pain in his thigh. 9720-08-2014 98. 9820-08-2014 99. Plain radiograph demonstrates a well- defined ,symmetric ,expansile, intramedullary lytic lesion of the proximal femur. 9920-08-2014 100. Solitary bone cyst is relatively common, non- neoplastic lesion, typically occurs in the skeletally immature patients, in the first and second decades of life (80% of cases). It is usually a unicameral cyst, which does not have an epithelial lining (hence not a true cyst) and is filled with serous fluid. About 80% of cases are diagnosed in two locations: humerus and proximal femur. In the long bone, SBC characteristically involves the metaphysis and diaphysis. Other possible skeletal sites are the ilium, talus, and calcaneus. 10020-08-2014 101. 10120-08-2014 102. Aneurysmal Bone Cyst (ABC) Aneurysmal Bone Cyst (ABC) is a rapidly growing, locally aggressive, intramedullary, vascular lesion, which characteristically produces blowout expansion of the affected portion of the bone. ABC can be primary (de novo) or secondary. Secondary ABC may develop in a pre-existing benign lesion such as chondroblastoma, chondromyxoid fibroma, giant cell tumour, and fibrous dysplasia, or be superimposed on a malignant tumor (osteosarcoma). Although ABC can occur at any age, the majority of patients are younger than 25. 10220-08-2014 103. Typical Clinical Presentation: A 17-year-old male presented with a slowly enlarging, painful lesion of the right clavicle 10320-08-2014 104. 10420-08-2014 105. 10520-08-2014 106. 10620-08-2014