Human Bones: Anatomy, Physiology, Disorders & Treatment Guide

1. Introduction

• Bones form the structural framework of the human body, providing support, protection, and mobility.
• The human skeleton consists of 206 bones classified into different types based on function and shape.
• Common bone-related disorders include fractures, osteoporosis, arthritis, and bone infections.

2. Anatomy of Bones

• Types of Bones:
  • Long Bones (e.g., femur, humerus) – Provide strength and mobility.
  • Short Bones (e.g., carpals, tarsals) – Allow limited movement but provide stability.
  • Flat Bones (e.g., ribs, skull) – Protect vital organs.
  • Irregular Bones (e.g., vertebrae) – Unique shape, specific functions.
  • Sesamoid Bones (e.g., patella) – Embedded in tendons for protection.
• Bone Composition:
  • Cortical (Compact) Bone: Dense outer layer, provides strength.
  • Trabecular (Spongy) Bone: Inner porous structure, supports marrow.
• Bone Marrow:
  • Red marrow (produces blood cells).
  • Yellow marrow (stores fat).
• Periosteum: Outer membrane supplying blood and nerves.

3. Physiology of Bones

• Bone Growth & Development:
  • Ossification: Cartilage turns into bone (endochondral ossification in long bones, intramembranous in flat bones).
  • Growth Plates (Epiphyseal Plates): Responsible for bone lengthening in children.
• Bone Remodeling:
  • Osteoblasts build bone.
  • Osteoclasts break down bone.
  • Regulated by parathyroid hormone (PTH), calcitonin, and vitamin D.
• Role in Calcium Homeostasis:
  • Bones store 99% of body’s calcium.
  • Calcium is released into the blood as needed.

4. Common Disorders & Pathophysiology

A. Osteoporosis

• Cause: Decreased bone density leading to fragile bones.
• Risk Factors: Aging, menopause, low calcium/vitamin D, sedentary lifestyle.

B. Fractures

• Types: Simple, compound, stress, comminuted, greenstick (children).
• Risk Factors: Trauma, weak bones (osteoporosis, cancer).

C. Arthritis

• Types:
  • Osteoarthritis: Wear and tear of joints.
  • Rheumatoid arthritis: Autoimmune joint destruction.
  • Gout: Uric acid crystal deposits in joints.

D. Osteomyelitis (Bone Infection)

• Cause: Bacterial infection (Staphylococcus aureus most common).
• Risk Factors: Open fractures, poor immunity, surgery complications.

E. Bone Tumours

• Types:
  • Benign: Osteochondroma, enchondroma.
  • Malignant: Osteosarcoma, Ewing’s sarcoma.
• Risk Factors: Genetic predisposition, radiation exposure.

5. Signs & Symptoms of Bone Disorders

• Early Symptoms:
  • Bone pain (persistent, worsening at night).
  • Joint stiffness or swelling.
• Advanced Symptoms:
  • Limited mobility.
  • Frequent fractures (weak bones).
  • Deformities (e.g., bowed legs in rickets).
• Red Flags:
  • Sudden, severe bone pain.
  • Unexplained weight loss with bone pain (possible cancer).
  • Open wounds over bone (infection risk).

6. When to See a Doctor

• Persistent bone/joint pain.
• Frequent fractures or slow-healing fractures.
• Joint swelling with redness and heat.

7. Emergency Signs Requiring Immediate Care

• Open fractures (bone exposed through skin).
• Severe bone pain after trauma.
• High fever with joint swelling (possible infection).

8. Diagnostic Process

• Clinical Examination: Swelling, tenderness, range of motion assessment.
• Laboratory Tests:
  • Calcium, Vitamin D levels (osteoporosis screening).
  • Inflammatory markers (CRP, ESR for arthritis, infection).
• Imaging Tests:
  • X-ray: First-line for fractures and bone density.
  • MRI/CT Scan: Detects soft tissue, tumours, complex fractures.
  • Bone Density Scan (DEXA): Diagnoses osteoporosis.
• Specialist Procedures: Bone biopsy (for tumours/infections).

9. Likely Diagnoses

• Fractures
• Osteoporosis
• Arthritis
• Bone Tumours
• Osteomyelitis

10. Treatment Options

A. Medications

• For Osteoporosis:
  • Bisphosphonates (Alendronate, Zoledronic acid) – Reduce bone loss.
  • Calcium & Vitamin D Supplements – Essential for bone health.
• For Arthritis:
  • NSAIDs (Ibuprofen, Diclofenac) – Pain relief.
  • DMARDs (Methotrexate, Hydroxychloroquine) – Used in rheumatoid arthritis.
• For Fractures & Pain Management:
  • Analgesics (Paracetamol, Opioids).
  • Muscle relaxants (Baclofen) – For spasms.
• For Bone Infections:
  • IV Antibiotics (Vancomycin, Ceftriaxone).
• Approximate Medication Costs (USD):
  • Bisphosphonates: $30–$200/month.
  • NSAIDs: $5–$50/month.
  • Biologics for arthritis (e.g., Humira): $2,000–$5,000/month.

B. Surgical/Procedural Interventions

• Fracture Fixation (ORIF) ($5,000–$30,000).
• Joint Replacement (Hip/Knee) ($10,000–$50,000).
• Bone Tumour Removal ($20,000–$100,000).
• Spinal Fusion (for severe spine fractures) ($40,000+).

C. Lifestyle Modifications & Home Remedies

• For Bone Strength: Weight-bearing exercises, calcium-rich diet.
• For Arthritis: Physiotherapy, joint-friendly exercises.
• For Osteoporosis Prevention: Sun exposure for vitamin D, avoid smoking.

11. Precautions & Prevention

• Adequate calcium & vitamin D intake.
• Regular weight-bearing exercises (walking, resistance training).
• Fall prevention for elderly (handrails, proper footwear).
• Screening for osteoporosis after age 50.

12. Prognosis & Recovery

• Fractures: Healing time varies (6–12 weeks).
• Osteoporosis: Progression can be slowed but not reversed.
• Arthritis: Chronic, managed with medication and therapy.
• Bone Infections & Tumours: Require aggressive treatment.

13. Cost of Treatment

• X-ray: $50–$300.
• Bone Density Scan (DEXA): $100–$500.
• Joint Replacement Surgery: $10,000–$50,000.
• Biologic Arthritis Treatment: $2,000+ per injection.

14. Frequently Asked Questions (FAQs)

1. How can I make my bones stronger?
   • Calcium, vitamin D, resistance training.
2. What is the best diet for bone health?
   • Dairy, leafy greens, nuts, fish.
3. How do I know if I have osteoporosis?
   • DEXA scan, frequent fractures, height loss.
4. What is the most common cause of fractures?
   • Trauma, osteoporosis.
5. How long does it take for a broken bone to heal?
   • 6–12 weeks depending on severity.
6. Can osteoporosis be cured?
   • No, but it can be managed.
7. What are the warning signs of bone cancer?
   • Persistent pain, swelling, fractures without trauma.
8. Is arthritis reversible?
   • Osteoarthritis is not; rheumatoid arthritis can be controlled.
9. Are bone infections serious?
   • Yes, they require urgent treatment.
10. Can children develop osteoporosis?

• Rarely, but nutritional deficiencies can affect bone growth.