Bone Structure & Function, Fractures & Fracture Healing Flashcards
What are the main functions of bones?
Provide structural support.
Enable mobility.
Protect internal organs.
Store essential minerals.
House bone marrow for blood cell production.
What are the two types of bone tissue?
Compact (Cortical) Bone: Dense, provides strength, forms the external layer.
Spongy (Trabecular) Bone: Honeycomb structure, found in epiphyses and axial skeleton.
What are the four cell types in bone?
Osteogenic Cells: Stem cells that differentiate into osteoblasts.
Osteoblasts: Build bone matrix and collagen fibers.
Osteocytes: Mature cells maintaining the matrix.
Osteoclasts: Clear and break down bone tissue.
What are the main components of the bone matrix?
25% water.
25% collagen fibers (providing flexibility).
50% crystallized mineral salts (e.g., calcium hydroxyapatite, providing hardness).
How does bone grow and remodel?
Growth in length occurs at the epiphyseal plate.
Remodelling involves bone deposition by osteoblasts and resorption by osteoclasts, maintaining strength and adapting to stress.
What are common disorders of bone growth?
Osteoporosis (low bone density).
Osteogenesis imperfecta (brittle bones).
Paget’s disease (abnormal remodeling).
Bone cancer and infections.
What is the role of blood supply in bones?
Periosteal Arteries: Supply outer compact bone.
Nutrient Arteries: Feed medullary cavity and inner compact bone.
Metaphyseal and Epiphyseal Arteries: Supply spongy bone and marrow.
How does mechanical stress affect bone health?
Weight-bearing activities build and strengthen bones.
Lack of activity leads to bone loss.
Relevant in rehabilitation and for elderly patients.
What factors influence bone remodeling?
Age (e.g., demineralization begins at 40 years).
Mechanical stress (weight-bearing activities).
Nutritional status (calcium and phosphate).
Hormonal levels (e.g., estrogen, parathyroid hormone).
Genetics and environmental factors.
What happens to bones as we age?
Demineralization: Begins at 40, worse in women after 45 years.
Osteopenia/Osteoporosis: Gradual loss of bone density.
Response to mechanical stress decreases.
What are the common types of fractures?
Severity-based: Open (compound), closed (simple), impacted, displaced, comminuted, compressed.
Shape-based: Spiral, oblique, transverse, greenstick, depressed.
Position-based: Proximal, distal, shaft, neck, epiphyseal.
Named fractures: Colles’, Pott’s.
What are the stages of fracture healing?
Haematoma formation: Blood clot forms in 6–8 hours; inflammation begins.
Fibrocartilaginous callus formation: Fibroblasts and chondroblasts produce collagen and cartilage.
Bony callus formation: Osteoblasts create spongy bone, joining broken ends (lasts 3–4 months).
Bone remodelling: Compact bone replaces spongy bone, restoring normal shape.
What factors affect the rate of fracture healing?
Type of fracture.
Site of fracture.
Vascular supply.
Age of the patient.
Movement at the fracture site.
Separation of bone ends.
Infection.
Bone pathology.
What are the clinical features of a fracture?
Pain and tenderness.
Swelling and bruising.
Deformity and angulation.
Impaired function.
Shock.
How are fractures classified by treatment approach?
Closed fractures: Sling, cast, or splint.
Open fractures:
Internal fixation (ORIF): For fractures near joints or comminuted fractures.
External fixation (OREF): For compound fractures at risk of infection.
What are some complications of fractures?
Delayed, mal-, or non-union.
Avascular necrosis.
Compartment syndrome.
Myositis ossificans.
Fat embolism.
Nerve, vessel, or tendon damage.
Osteoarthritis or growth impairment.
What are bone disorders affecting development?
Agenesis.
Osteogenesis imperfecta.
Spina bifida.
Achondroplasia.
What are bone disorders linked to remodelling and aging?
Osteopenia.
Osteoporosis.
Hormonal imbalances (e.g., hyper/hypoparathyroidism, postmenopausal osteoporosis).
Nutritional deficiencies (e.g., rickets, scurvy).
What are the phases of age-related changes in bone mass?
Peak bone mass is achieved in the 20s.
After the mid-30s, gradual bone loss occurs.
Bone loss accelerates in women post-menopause.
What are the clinical signs of osteoporosis?
Increased risk of fractures.
Loss of height.
Kyphosis (curved spine).
Bone fragility.
