Skeletal System Study Notes

Structure of the Skeletal System

  • The skeletal system consists of various components that contribute to its overall structure, function, and potential dysfunctions.
    • Components of the Skeletal System:
    • Structure
    • Skeleton
    • Function
    • Dysfunctions

Axial vs. Appendicular Skeleton

  • Axial Skeleton:
    • Comprises the bones of the skull, vertebral column, and rib cage.
    • Provides support and protection for the brain, spinal cord, and thoracic organs.
  • Appendicular Skeleton:
    • Includes the bones of the limbs and their attachment points to the axial skeleton.
    • Allows for movement and manipulation of the environment.

Types of Bones

  • Long Bones:
    • Specific bones within this category include:
    • Clavicle
    • Humerus
    • Radius
    • Ulna
    • Femur
    • Metacarpus
    • Phalanges
    • Tibia
    • Fibula
    • Metatarsus
    • Long bones require splinting and may pose a risk of hemorrhage due to their size and location.

Bone Anatomy

  • External Structure vs. Internal Structure:
    • External Structure:
    • Cartilage covering
    • Internal Structure:
    • Diaphysis:
      • Central part of the bone, includes medullary cavity (hollow area)
      • Contains yellow marrow (fat storage)
    • Epiphysis:
      • Ends of long bone, contains spongy bone and red marrow.
      • Surrounded by compact bone, covered by periosteum.

Facial Bones

  • Particular Bones:
    • Zygomatic
    • Mandible
    • Maxilla
    • Hyoid bone
    • Plays a role in the skeletal structure and functions of the neck region.

Vertebral Column

  • The thoracic cage and vertebrae are organized as follows:
    • Cervical (7) vertebrae
    • Thoracic (12) vertebrae
    • Lumbar (5) vertebrae
    • Sacrum (5, fused) vertebrae
    • Coccyx (4, fused) vertebrae
  • Rib Categories:
    • True ribs (1-7)
    • False ribs (8-12)
    • Include floating ribs (11, 12).
  • Key Features of the Thoracic Cage:
    • Jugular notch, clavicular notch, manubrium, body of sternum, xiphoid process, intercostal spaces, costal cartilage, costal margin.

Classification of Boney Structures

  • Differentiating bone shapes assists in predicting their functions and potential dysfunctions can help in diagnosing conditions.
  • Bone Shapes Include:
    • Long bones, short bones, flat bones, irregular bones, and sesamoid bones.
  • Function-Related classifications:
    • Joint movement types including immovable, slightly moveable, and freely moveable joints such as pivot, hinge, ball-and-socket, condyloid, saddle, and plane joints.

Bone Composition

  • Bone is Living Connective Tissue:
    • Composed of:
    • Collagen: Provides flexibility and tensile strength.
      • Tendons connect bone to muscle.
      • Ligaments connect bone to bone.
    • Calcium: Provides strength and is crucial for bone density.

Hormonal Regulation of Calcium**

  • Calcitonin:
    • Produce by the thyroid gland, it lowers blood calcium levels by:
    • Inhibiting renal reabsorption of calcium, thus increasing excretion in urine.
    • Inhibiting calcium absorption by the intestines.
    • Promoting deposition of calcium in bones, thereby stimulating osteoblasts and inhibiting osteoclast activity.
  • Parathyroid Hormone (PTH):
    • Secreted by the parathyroid glands, it raises blood calcium levels through:
    • Promoting calcium reabsorption in the kidneys.
    • Stimulating release of calcium from bones.
    • Enhancing absorption of calcium from the intestines via Vitamin D.

Cartilage Functionality

  • Cartilage Provides:
    • Structural support and framework for calcification.
    • Cushioning at articulations, preventing friction between bones at joints.
    • Associated structures include synovial fluid and ligaments.

Skeletal Function and Disorders

  • Primary Functions of Bones:
    • Provide shape, enable movement, protect internal organs, produce blood cells, and store minerals.
  • Common Issues Include:
    • Inflammation, tendonitis, bursitis, arthritis, and osteomyelitis, characterized by pain, redness, swelling, and tenderness at joints and surrounding tissues.

Bursitis and Breakdown of Bone Health

  • Bursitis:
    • Inflammation of the bursa, presented with swelling and tenderness.
    • Common locations include shoulder, elbow, hip, knee, and foot.

Infection and Osteomyelitis Stages

  • Stages of Osteomyelitis:
    1. Initiation of infection impacting periosteum.
    2. Development stages with possible abscess (pus).
    3. Presentation of sequestrum (dead bone).
    4. Formation of involucrum (new bone tissue).

Types of Arthritis and Their Effects

  • Osteoarthritis:
    • Characterized by joint space narrowing, cartilage loss, and osteophyte development.
  • Rheumatoid Arthritis:
    • Autoimmune disorder leading to joint inflammation.
  • Gout: Focusing on uric acid precipitation in joints leading to painful inflammation.