Chap 10 - Skeletal System Hw4 PDF

MRD515 SKELETAL SYSTEM  LEARNING OBJECTIVES 1 2 3 4 5 Describe the structure Explain how to assess Categorize medical Discuss the causes, Explore how different of t...

MRD515 SKELETAL SYSTEM  LEARNING OBJECTIVES 1 2 3 4 5 Describe the structure Explain how to assess Categorize medical Discuss the causes, Explore how different of the skeletal system, the quality and conditions affecting the symptoms, and imaging methods are from its visible features accuracy of skeletal X- skeleton as congenital, expected outcomes of used to diagnose and to microscopic details. ray images. inflammatory, arthritic, skeletal diseases. treat skeletal disorders. or neoplastic.  The skeletal system consists of 206 bones, serving essential functions such as support, protection, ANATOMY AND movement, and blood cell production. It holds a significant portion of the body's calcium and phosphorus. PHYSIOLOGY It's categorized into the axial (80 bones) and appendicular (126 bones) skeletons. Bones are a unique connective tissue due to their calcium phosphate matrix. They can be compact (dense) or cancellous (spongy). Bone marrow, found within the medullary canal, includes red marrow (for blood cell production) and yellow marrow (mainly fat). Cell Activity: Osteoblasts (bone-forming cells) and osteoclasts (bone-breaking cells) play crucial roles in bone growth, thickening, and maintenance, impacting calcium and phosphorus balance.  Bone Types: Bones are categorized by shape: long, short, flat, or irregular. Long bones have a shaft (diaphysis) and expanded ends (epiphyses). Growth Zones : Growing bones have a cartilaginous growth plate (metaphysis) between epiphysis and diaphysis, appearing radiolucent in children and calcifying in adults. Periosteum: This fibrous membrane covers bones, except joints, and supplies blood to the bone. Osteoblasts in the periosteum thicken bones in response to physical stress. Disuse Atrophy: Lack of weight-bearing causes bone decalcification and thinning. Joint Types: Joints connect bones and can be fibrous (immovable), cartilaginous (slightly movable), or synovial (freely movable). Synovial Joints: These include articular cartilage, ligaments, and synovial membranes secreting synovial fluid for lubrication. IMAGING CONSIDERATIONS Various imaging modalities play distinct roles in assessing skeletal pathology, from radiography and MRI's soft tissue detail to CT's bone- specific capabilities and nuclear medicine's whole-body approach. Understanding their strengths and applications is crucial for accurate diagnosis and management.  Radiography: Proper orientation and recognition of radiographic projection are essential. Technique selection influences diagnosis quality, ensuring adequate penetration and visibility of trabecular pattern. Examination of soft tissue areas reveals muscle atrophy, swelling, calcifications, foreign bodies, or gas indicating disease. Bone analysis helps detect fractures, dislocations, congenital anomalies, or deformities.  Magnetic Resonance Imaging (MRI): Provides superior soft tissue detail with excellent contrast resolution. Preferred for soft tissue tumors in extremities. Valuable for joint evaluation, e.g., knee and shoulder. Improved MRI technology detects musculoskeletal subtleties. Useful in visualizing subtle bone marrow abnormalities. Expanding role in trauma medicine with open- bore and short-bore technologies.  Computed Tomography (CT): Performs noninvasive examinations, even in trauma cases. Defines fractures, dislocations, joint abnormalities, and spinal disorders. Excellent for bone details, trabecular patterns, and assessing bone and soft tissue involvement in tumors. Used in bone mass loss assessment, especially in vertebral bodies.  Nuclear Medicine Procedures: Offers the advantage of whole-body imaging for assessing pathology, distinguishing old injuries from new problems. Bone scan remains standard for metastatic processes, demonstrating bone metabolic reactions. Sensitive for various traumatic or inflammatory skeletal diseases. Emerging use of PET scanning, e.g., 18F-NaF (2- deoxy-2-[18F] fluoro-D-glucose), for diagnosing and staging metastatic disease. Potential applications in back pain, child abuse confirmation, osteomyelitis, trauma, arthritis, avascular necrosis, and various bone diseases.  Osteogenesis Imperfecta (OI) Rare genetic skeletal disorder, often called brittle bone disease. Typically autosomal dominant. Bones fracture easily with no obvious cause or injury Diagnosis: Prenatal testing (cultured skin fibroblasts) for types II, III, and IV. Genes: Mutations in COL1A1, COL1A2, CRTAP, LEPRE1 genes affecting type I collagen (main component of bone, skin, tendon). Effects: Deficient and imperfect bone, skin, sclera, inner ear, and teeth formation. Clinical Groups: OI Congenita: Present at birth, multiple fractures, limb deformities, dwarfism, potential fatality. OI Tarda: Fractures later in life, halt in adulthood, potential hearing issues (otosclerosis). Radiographic Signs: Multiple fractures at different healing stages, reduced bone mass, thin cortex, delicate, widely separated trabeculae. Importance: Complex genetic disorder requiring early diagnosis and care. Varies in severity.  Frequency: Most common inherited skeletal disorder. Occurrence: 1 in 15,000 to 40,000 newborns. Achondroplasia Inheritance: Autosomal dominant (gene FGFR3 at 4p chromosome location), no generation skipping. Transmission: About 50% chance of passing it to offspring. Pathophysiology: Impairs endochondral bone formation, hinders cartilage-to-bone conversion in epiphyses, disrupting longitudinal bone growth. Clinical Features: Dwarfism with normal trunk size and shortened extremities. Adult height typically not exceeding 4 feet. Additional features include lumbar spine lordosis, bowed legs, midface hypoplasia, and narrowing of the foramen magnum (neural compression). Achondroplasia Prenatal Diagnosis: Ultrasonography may be used. Treatment: Orthopedic surgery for complications. Ilizarov procedure for limb lengthening. Bone age radiographic studies for monitoring. Growth hormone (GH) injections in clinical trials (impact on cardiovascular system under study). Importance: Requires careful management and genetic counseling, affecting height and skeletal structure.  Refers to disorders causing increased bone density and defective bone contour, often termed as "marble bone.” Result from mutations at the CLCN7 gene. Types: Osteopetrosis Infantile Malignant CLCN7-related Autosomal Recessive Osteopetrosis (ARO): Onset in infancy. Intermediate Autosomal Osteopetrosis (IAO): Develops in childhood. Autosomal Dominant Osteopetrosis Type II (ADOII): Occurs in late childhood or adolescence. Bone Characteristics: Abnormally heavy, compact, and brittle bones. Associated Pathologies: Include osteosclerosis (thickening of trabecular/spongy bone), craniotubular dysplasias (abnormal growth)/craniotubular hyperostosis (widening of cortical/compact bone). Radiographic Features: Increased bone density and cortex thickness. More trabeculae, marked reduction in marrow space. Abnormal bone modeling. Importance for Technologist: Abnormal bone density may require increased exposure factors for radiography. Adequate radiographic density may be challenging to achieve.  Syndactyly: Failure of fingers/toes to separate, causing webbed appearance. Hand and Foot Polydactyly: Presence of extra digits. Malformations Clubfoot (Talipes): Congenital malformation of the foot, often turned inward at the ankle.  Developmental Dysplasia of the Hip (DDH) Cause: Malformation of the acetabulum, leading to femoral head displacement. Presentation: May be unilateral or bilateral, affecting females more than males. Risk factors include breech position, first child, or low amniotic fluid. Diagnosis: Sonography and radiographic measurements to assess acetabular development. Treatment: Early immobilization through casting or splinting to allow for normal joint development; untreated cases may result in complications like limb length discrepancy.  Vertebral Anomalies Scoliosis: Abnormal lateral curvature of the spine, often convex to the right in the thoracic region and to the left in the lumbar region. Types: Structural scoliosis (with vertebral rotation). Nonstructural scoliosis (no vertebral rotation). Radiographic Assessment: Initial AP or PA and lateral standing radiographs, regular follow-ups, measurement of spine curvature. Treatment: Bracing or casting for curves of 25-35 degrees; surgical spinal fusion for curves >40 degrees. Transitional Vertebra: Takes on characteristics of both adjacent vertebrae, often seen at the junctions between thoracic and lumbar or lumbar and sacral spines. Spina Bifida Definition: Incomplete closure of vertebral canal, often in lumbosacral area. Severity: May range from no visible abnormality (spina bifida occulta) to involvement of spinal cord/nerve root leading to paralysis. Treatment: Varied, based on extent and severity of the anomaly, requires involvement of multiple medical specialists. Cranial Anomalies Craniosynostosis: Premature closure of cranial sutures leading to abnormal head shape, associated with Apert syndrome and requiring surgical correction. Anencephaly: Congenital abnormality where brain and cranial vault don't form; often fatal shortly after birth, can be detected prenatally by ultrasonography, cause is multifactorial. INFLAMMATORY DISEASES  Osteomyelitis: Infection of the bone and bone marrow caused by pathogenic microorganisms. Can result from hematogenous spread, contiguous site infection, or direct introduction of microorganisms. Common Signs and Symptoms: Dull pain, heat in the affected area, intermittent low-grade fever. Most Common Affected Bones: Ends of long bones (distal femur, proximal tibia, humerus, and radius in children; vertebrae in adults). Common Pathogens: Staphylococcus aureus, Streptococci, Group B Streptococci, Escherichia coli. Radiographic Features: Early stages may not show specific changes. Later stages show soft tissue swelling, joint effusion, cortical erosion, and joint space narrowing. Diagnosis: Elevated ESR or CRP levels; blood and synovial fluid analysis. Treatment: Antibiotics, surgical drainage of pus if necessary. Tuberculosis: Chronic inflammatory disease caused by Mycobacterium tuberculosis. Most commonly affects hip, knee, and spine. Radiographic Features: "Worm- eaten" appearance of epiphyses, destruction of articular cartilage, potential joint space infection. Spinal Tuberculosis (Pott's Disease): Softening and collapse of vertebrae, paravertebral abscess, spinal cord compression. Arthropathies: A group of joint disorders, including arthritis, bursitis, tendonitis, and tenosynovitis. Infectious Arthritis: Caused by bacteria entering joints through various means. Symptoms: Rapid onset of joint pain, swelling, and fever. Radiographic Changes: Joint effusion, joint space narrowing, recalcification and sclerosis during healing. Rheumatoid Arthritis (RA): Chronic autoimmune disease affecting synovial tissues and joints. Typically begins in peripheral joints, especially hands and feet. Radiographic Changes: Soft tissue swelling, osteoporosis, cortical erosion, joint space narrowing, joint deformity. Diagnosis: Serologic rheumatoid factor (RF), erythrocyte sedimentation rate (ESR), C- reactive protein (CRP) levels. Treatment: Medications, surgery for severe cases. Ankylosing Spondylitis: Progressive form of arthritis, mainly involving the spine. Common in young men. Symptoms: Low back pain, morning stiffness, fatigue. Radiographic Features: Bilateral sacroiliac joint narrowing, calcification of spinal ligaments, "bamboo spine." Diagnosis: HLA-B27 test Treatment: NSAIDs (Nonsteroidal anti- inflammatory drugs), exercise, postural training, DMARDs (Disease-modifying antirheumatic drugs). Osteoarthritis: Most common type of arthritis, often associated with aging. Affects large weight-bearing joints (e.g., hips, knees, ankles). Radiographic Features: Loss of articular cartilage, osteophyte formation, bone sclerosis. Treatment: Medications, exercise, surgical interventions.  Gouty Arthritis: Metabolic disorder resulting in uric acid crystal deposits in joints. Symptoms: Acute attacks with inflammation, tophi formation. Radiographic Features: Erosion with overhanging edges. Treatment: Medications to promote uric acid excretion or inhibit its production.  Inflammation of tendons or tendon sheaths. Tendonitis and May cause calcifications in chronic cases. Treatment: Medications, corticosteroid Tenosynovitis: injections, surgical intervention if necessary. Bursitis: Inflammation of bursae (synovial membrane- lined sacs). Common areas: shoulder, elbow, knee, hip. Treatment: NSAIDs, aspiration, corticosteroid injections, or surgical excision if necessary. Ganglion Cyst: Cystic swelling connected to a tendon sheath. Common in the wrist. Treatment: Aspiration, aspiration with corticosteroid injection, or surgical excision if symptomatic. VERTEBRAL COLUMN INJURIES Causes: Include direct trauma, hyperextension-flexion injuries, osteoporosis, and metastatic destruction. Radiographic Indications: Interruption of smooth, continuous lines formed by stacked vertebrae, resulting from hyperextension or hyperflexion injuries. Anterospondylolisthesis (Spondylolisthesis): Anterior slipping of vertebrae, commonly occurring at L5-S1 junction. Managed conservatively or surgically based on severity (graded I to IV).  Spondylolysis: Cleft or breaking down of vertebral body, often in the arch of the fifth lumbar vertebra. Seen on oblique lumbar spine projection. Disk Disorders: Myelography or MRI used for evaluation. MRI noninvasive and superior for spinal cord, nerve roots, and disk assessment. Fractures: CT preferred for bone anatomy assessment. NEOPLASTIC Primary vs. Metastatic: Primary bone tumors are more common in children, while metastatic bone lesions are more common in adults. DISEASES Common Benign Tumors: Osteoma, osteochondroma, and giant cell tumor. Common Malignant Tumors: Osteosarcoma, Ewing tumor, and multiple myeloma. Diagnosis Factors: Age, pattern of bone destruction, tumor location, and tumor's position within the bone are crucial for radiographic diagnosis. Radiographic Indications: Benign tumors show expansion of bone with sharp, sclerotic margins; malignant neoplasms infiltrate and destroy anatomic margins.  Bone Tumor Markers: Alkaline phosphatase, osteonectin, osteocalcin, and collagen can serve as potential markers. Radiographic Evaluation: Radiographs, CT scans, and MRI play significant roles in diagnosis and management. Staging System: Enneking's system classifies both benign and malignant bone tumors based on histologic grade, local extent, and presence of metastatic disease. Common Benign Tumors: Osteochondroma: Common, often asymptomatic, may lead to pathologic fractures. Osteoma: Slow-growing, usually in the skull, may cause obstruction. Endochondroma: Affects small bones of hands and feet, multiple growths may occur. Simple Unicameral Bone Cyst: Fluid-filled, frequently in long bones of children. Aneurysmal Bone Cyst: Blood-filled cysts, may appear in the metaphysis of long bones. Osteoid Osteoma/Osteoblastoma: Characterized by pain, treated with surgical excision or percutaneous injection. Giant Cell Tumor (Osteoclastoma): May be benign or malignant, often affects the ends of long bones. Osteochondroma (Exostosis) Most common benign bone tumor, common in men. Originates in metaphysis (growth zone) between epiphysis and diaphysis. Frequently found in lower femur or upper tibia. Capsule of growing cartilage attached by bony stalk. Often affects the knee joint. Can be solitary or multiple. Multiple hereditary exostoses (MHE) linked to genetic mutations (EXT genes). MHE may transform into chondrosarcoma. Typically asymptomatic but can cause pathologic fractures. Radiologic appearance: Osteosclerotic or osteoblastic. CT and MRI used for differentiation from malignancies. Osteoma: Less common benign growth, often in the skull. Composed of dense, well-circumscribed normal bone. Typically found in orbits or paranasal sinuses. Slow-growing, mostly non-significant. May cause obstruction or interfere with nearby structures. Associated with "hyperostosis frontalis interna" in the skull. Endochondroma: Slow-growing benign tumor composed of hyaline cartilage. Occurs in the marrow space. Commonly affects small bones of hands and feet in people aged 30-40. Expands cortical bone, causing thinning. Radiographically: Radiolucent lesion with small calcifications. Well-circumscribed, "bubbly" appearance. Erosion of cortex can lead to pain, swelling, and pathologic fractures. Multiple growths (enchondromatosis) may transform malignantly (25-30% risk). CT and MRI used to differentiate from chondrosarcomas. Simple Unicameral Bone Cyst (UBC): Fibrous tissue wall filled with fluid. Common in children, especially in humerus and proximal femur. Often noticed due to pain or pathologic fractures. Radiographically: Radiolucent lesion with clear margins. May heal on its own (small cysts) or require surgical intervention (larger cysts). Treatment includes surgical excision and bone chip packing or percutaneous steroid injection. Aneurysmal Bone Cyst (ABC): Not a true neoplasm, idiopathic condition. Common in individuals under 20 years old. Occurs in metaphysis of long bones, especially lumbar vertebrae. Composed of blood-filled arteriovenous communications. Slow-growing with symptoms like pain and swelling. Radiographically: Thinning of cortex, well- circumscribed lesion, soft tissue extension. Associated with USP6 oncogene overactivity. Treated with surgical removal and bone grafting or radiation therapy (caution due to post-radiation malignancies).  Osteoid Osteoma and Osteoblastoma: Benign tumors of the skeletal system. Osteoid osteomas are smaller (