bone

• Bone


  Tissue that makes up the skeletal system

  
• Compact bone


  • Dense, hard outer layer of bone
  • Surrounds the medullary cavity

  
• Spongy bone


  • Lattice-like structure of thin columns called trabeculae
  • Contains marrow spaces

  
• Bone formation


  1. Cartilage and fibrous membrane initially

  2. Most cartilage replaced by bone

  3. Few cartilages remain in adults

  
• Epiphysis


  Larger rounded ends of long bones, covered in articular cartilage

  
• Metaphysis


  Area between diaphysis and epiphysis, includes epiphyseal plate
• Diaphysis


  Long central shaft of long bone, thick collar of compact bone surrounding medullary cavity

  
• Epiphyseal plate


  Hyaline cartilage in adolescents, allows bone elongation

  
• Epiphyseal line


  Replaces epiphyseal plate in adults, cartilage replaced by calcified bone

  
• Periosteum


  Double-layer membrane covering external surface of bone

  
• Medullary cavity


  Space within diaphysis containing fatty yellow bone marrow in adults

  
• Endosteum


  Covers inner bone surface, trabeculae, and medullary cavity

  
• Short, irregular, and flat bones

  • Consist of compact and spongy bone

  
• Osteon


  Structural unit of compact bone, contains central Haversian canal, concentric lamellae, lacunae, osteocytes, and canaliculi

  
• Trabeculae


  Thin columns of spongy bone, oriented along lines of stress

  
• Bone cells


  • Osteogenic cells
  • Osteoblasts
  • Osteoclasts
  • Osteocytes
• Extracellular matrix of bone

  • 25% water
  • 25% collagen fibers
  • 50% crystallized mineral salts (mainly calcium phosphate)
• Bone is richly supplied with blood and nerves

  
• Divisions of the skeletal system

  • Axial skeleton
  • Appendicular skeleton

  
• Types of bones


  • Long
  • Short
  • Flat
  • Irregular
  • Sesamoid

  
• Bones of the axial skeleton


  • Skull
  • Vertebral column
  • Ribs
  • Sternum

  
• Regions of the vertebral column

  • Cervical
  • Thoracic
  • Lumbar
  • Sacrum
  • Coccyx
• Bones of the upper limb

  • Shoulder
  • Arm
  • Forearm
  • Hand

  
• Vertebrae


  • Coccyx (4 fused coccygeal vertebrae)
  • Cervical vertebrae (C1-C7)
  • Thoracic vertebrae (T1-T12)
  • Lumbar vertebrae (L1-L5)
  • Sacrum (5 sacral vertebrae)
  • Coccyx (4 fused coccygeal vertebrae)
• The atlas (C1) is the first cervical vertebra
• The axis (C2) is the second cervical vertebra
• Thoracic vertebrae articulate with the ribs
• Lumbar vertebrae provide for the attachment of the large back muscles
• The sacrum is a triangular bone formed by the union of five sacral vertebrae (S1-S5)

  
• The sacrum serves as a strong foundation for the pelvic girdle
• The coccyx is triangular in shape and is formed by the fusion of usually four coccygeal vertebrae
• Vertebral Column


  • Consists of 7 cervical, 12 thoracic, 5 lumbar, 5 sacral, and 4 coccygeal vertebrae
• Appendicular Skeleton


  • The primary function is movement
  • It includes bones of the upper and lower limbs
  • Girdles attach the limbs to the axial skeleton

  
• Regions of the Upper Limb

  • Shoulder
  • Arm
  • Forearm
  • Hand
• Each upper limb has 32 bones

  
• Bones of the Pectoral (Shoulder) Girdle

  • Scapula
  • Clavicle

  
• Bones of the Free Part of the Upper Limb

  • Humerus (arm)
  • Ulna (forearm)
  • Radius (forearm)
  • 8 carpals (wrist)
  • 19 metacarpal and phalanges (hand)

  
• Humerus


  • Longest and largest bone of the free part of the upper limb
  • Proximal ball-shaped end articulates with the glenoid cavity of the scapula
  • Distal end articulates at the elbow with the radius and ulna

  
• The lower limb is divided into the gluteal region (the major bones forming the hip girdle), thigh, leg, and foot
• Regions of the Lower Limb

  • Gluteal region (hip girdle)
  • Thigh
  • Leg
  • Foot