Skeletal System Quiz

Skeletal System Overview

• The skeletal system comprises 206 bones, providing support, protection, movement, and blood cell production.
• Bones are a unique connective tissue, with a calcium phosphate matrix, existing in compact (dense) or cancellous (spongy) forms.
• Bone marrow, located within the medullary canal, includes red marrow (blood cell production) and yellow marrow (mainly fat).
• Osteoblasts (bone-forming cells) and osteoclasts (bone-breaking cells) control bone growth, thickening, and maintenance, influencing calcium and phosphorus balance.

Learning Objectives

• Describe the skeletal system's structure, from macro to micro details.
• Evaluate the quality and accuracy of skeletal X-ray images.
• Classify skeletal medical conditions (congenital, inflammatory, arthritic, or neoplastic).
• Detail the causes, symptoms, and outcomes of skeletal diseases.
• Discuss various imaging methods for diagnosing and treating skeletal disorders.

Bone Types and Zones

• Bones are classified by shape (long, short, flat, irregular).
• Long bones have a shaft (diaphysis) and expanded ends (epiphyses).
• Growth zones (metaphyses) involve cartilaginous plates, showing radiolucency in children and calcification in adults.
• Periosteum, a fibrous membrane, covers bones (except joints) and supplies blood for bone thickening in response to stress.

Joint Types

• Fibrous joints are immovable.
• Cartilaginous joints are slightly movable.
• Synovial joints are freely movable, including articular cartilage, ligaments, and synovial fluid for lubrication.

Imaging Considerations

• Various imaging methods (radiography, MRI, CT, nuclear medicine) assess skeletal pathology.
• Understanding their strengths and applications is crucial for accurate diagnosis and management.

Imaging Specifics

• Radiography: Proper orientation and projection are essential for quality diagnosis. Evaluates soft tissue, muscle atrophy, and possible disease markers.
• MRI: Superior soft tissue detail, preferred for joint evaluation, soft tissue tumors, and subtle bone marrow abnormalities. Useful in trauma medicine.
• CT: Noninvasive, used for trauma cases, fractures, dislocations, joint and spinal abnormalities, bone and soft tissue assessment, particularly in vertebral bodies.
• Nuclear medicine: Whole-body imaging, used for assessing pathology, evaluating metastatic processes, various inflammatory/traumatic skeletal diseases, and staging cancers.

Specific Skeletal Disorders

• Osteogenesis Imperfecta (OI): Rare genetic disorder (often called brittle bone disease) with mutations in collagen genes, resulting in deficient and imperfect bone formation.
• Achondroplasia: Inherited skeletal disorder causing dwarfism with shortened limbs and other specific craniofacial features. Diagnosis through prenatal ultrasonography and treatment includes orthopedic surgeries and bone growth hormone interventions. Diagnosing it early and ongoing care are required.
• Osteopetrosis: Characterized by abnormally heavy, compact, and brittle bones due to mutations in the CLCN7 gene.
• Hand and Foot Malformations: Syndactyly (webbed fingers/toes), Polydactyly (extra digits), and Clubfoot (inward turned foot).
• Developmental Dysplasia of the Hip (DDH): Malformation of the acetabulum leading to femoral head displacement.
• Vertebral Anomalies: Scoliosis (lateral curvature of the spine) and Transitional Vertebrae (abnormalities in vertebra structure between regions).
• Spina Bifida: Incomplete closure of the vertebral canal. Range from no visible abnormality to involving the spinal cord and nerve roots, potentially causing paralysis.
• Cranial Anomalies: Craniosynostosis (premature closure of cranial sutures) and Anencephaly (absence of major portions of the brain and skull).

Inflammatory Diseases

• Osteomyelitis: Infection of the bone and marrow, causing pain, fever, and tissue swelling. Caused by pathogenic microorganisms, often through the blood or from an infection close to the bone.
• Tuberculosis: Chronic inflammatory disease affecting bones, especially in the hips, knees, and spine. Mycobacterium tuberculosis is the causative agent. Features include "worm-eaten" appearance of epiphyses, cartilage destruction, and potential joint/spinal infection.
• Arthropathies: A group of joint disorders, including arthritis, bursitis, tendonitis, and tenosynovitis.
• Infectious Arthritis: Infection of joints by various bacteria, resulting in sudden onset pain, swelling, and fever. Joint effusion, narrowing of joint space, and sclerosis during recovery can be seen on imaging.
• Rheumatoid Arthritis (RA): Chronic autoimmune disease affecting synovial tissues and multiple joints, typically first appearing in the hands and feet.
• Ankylosing Spondylitis: Progressive arthritis mainly targeting the spine.
• Osteoarthritis: Most frequent arthritis type, often associated with aging and weight bearing in joints, including hips, knees, and ankles.
• Gouty Arthritis: Metabolic disorder involving uric acid build-up in joints, causing acute attacks and inflammation.

Soft Tissue and Synovial Disorders

• Tendonitis and Tenosynovitis: Inflammation affecting tendons and tendon sheaths, sometimes with chronic complications leading to calcification.
• Bursitis: Inflammation of bursae (small sacs lined with synovial membrane) surrounding shoulder, elbow, knee, or hip joint.
• Ganglion Cyst: Cystic swelling connected to a tendon sheath, often found in the wrist.

Vertebral Column Injuries

• Causes include direct trauma, hyperextension-flexion injuries, osteoporosis, and metastatic destruction.
• Anterospondylolisthesis is a slipping of one vertebra over another, often at the L5-S1 junction, and can cause nerve compression.
• Radiologic signs involve interruptions in continuous vertebral lines.
• Spondylolysis is a breaking down of the vertebral body, typically in the L5 vertebra.

Neoplastic Diseases

• Benign tumors are usually smaller, well-defined masses with no significant tissue involvement, while malignant tumors are larger, invasive, and often necessitate major interventions.
• Common benign tumors include Osteoma, Osteochondroma, Endochondroma, Simple Unicameral Bone Cyst, Aneurysmal Bone Cyst, Osteoid Osteoma, and Osteoblastoma.
• Common malignant tumors include osteosarcoma, Ewing sarcoma, and chondrosarcoma.

Metastatic Bone Cancer

• Most common malignant bone tumors are metastases originating from other malignancies.
• Sites most vulnerable are red bone marrow rich parts, such as the spine, sternum, pelvis, skull, vertebrae.
• Bone scans help identify numerous irregular areas indicating increased uptake in areas. Typical radiographic signs include altered bone density and architecture.

Other Common Benign Tumors (Briefly covered, in common tumors section)

• Osteoid Osteoma: often in the femur, tibia, or spine, intense pain. May require surgical intervention.
• Osteoblastoma: larger than osteoid osteomas, can be non-painful.

Additional Notes

• The information provided is a broad summary; each condition warrants more in-depth study.
• Treatment options vary based on the disease, stage, and patient factors.