iskilital

• Skeletal System


  Parts include: Bones (skeleton), Joints, Cartilages, Ligaments

  
• Divisions of the Skeletal System

  • Axial skeleton (skull, ribs and vertebra)
  • Appendicular skeleton (pelvis, extremities)

  
• Functions of Bones


  • Support of the body
  • Protection of soft organs
  • Movement due to attached skeletal muscles
  • Storage of minerals and fats
  • Blood cell formation

  
• The adult skeleton has 206 bones
• Spongy bone


  Small needle-like pieces of bone with many open spaces

  
• Classification of Bones on the Basis of Shape

  • Long bones
  • Short bones
  • Flat bones
  • Irregular bones

  
• Long bones


  • Typically longer than wide
  • Have a shaft with heads at both ends
  • Contain mostly compact bone

  
• Examples of long bones

  • Femur, humerus

  
• Short bones


  • Generally cube-shape
  • Contain mostly spongy bone

  
• Examples of short bones

  • Carpals, tarsals
• Flat bones


  • Thin and flattened, usually curved
  • Thin layers of compact bone around a layer of spongy bone

  
• Examples of flat bones


  • Skull, ribs, sternum

  
• Irregular bones


  • Irregular in shape
  • Do not fit into other bone classification categories

  
• Examples of irregular bones

  • Vertebrae and hip
• Diaphysis


  Shaft of a long bone, composed of compact bone

  
• Epiphysis


  Ends of a long bone, composed mostly of spongy bone

  
• Articular cartilage


  Covers the external surface of the epiphyses, made of hyaline cartilage, decreases friction at joint surfaces
• Medullary cavity


  Cavity of the shaft, contains yellow marrow (mostly fat) in adults, contains red marrow (for blood cell formation) in infants
• In embryos, the skeleton is primarily hyaline cartilage

  
• During development, much of this cartilage is replaced by bone

  
• Cartilage remains in isolated areas like the bridge of the nose, parts of ribs, and joints
• Epiphyseal plate growth


  1. New cartilage is continuously formed

  2. Older cartilage becomes ossified

  3. Cartilage is broken down

  4. Bone replaces cartilage

  
• Bones are remodeled and lengthened until growth stops

  
• Bones change shape somewhat and grow in width

  
• Bone fracture


  A break in a bone
• Types of bone fractures

  • Closed (simple) fracture - break that does not penetrate the skin
  • Open (compound) fracture - broken bone penetrates through the skin

  
• Bone fracture treatment


  Reduction and immobilization - Realignment of the bone

  
• Common types of fractures

  • Transverse
  • Oblique
  • Spiral
  • Comminuted
  • Impacted

  
• Axial skeleton


  Forms the longitudinal part of the body

  
• Parts of the axial skeleton

  • Skull
  • Vertebral column
  • Bony thorax

  
• Skull


  Two sets of bones - Cranium and Facial bones, joined by sutures, only the mandible is attached by a freely movable joint

  
• The hyoid bone is the only bone that does not articulate with another bone

  
• Vertebral column


  Vertebrae separated by intervertebral discs, has a normal curvature, each vertebrae is given a name according to its location

  
• Bony thorax


  Forms a cage to protect major organs, made up of the sternum, ribs, and thoracic vertebrae
• Pectoral (shoulder) girdle


  Composed of the clavicle and scapula, allows the upper limb to have exceptionally free movement
• Bones of the upper limb

  • Humerus (arm)
  • Ulna, Radius (forearm)
  • Carpals (wrist), Metacarpals (palm), Phalanges (fingers)

  
• Pelvic girdle


  Composed of the hip bones (ilium, ischium, pubic bone), protects reproductive organs, urinary bladder, and part of the large intestine, supports the weight of the upper body
• Bones of the lower limb

  • Femur (thigh)
  • Tibia, Fibula (leg)
  • Tarsus (ankle), Metatarsals (sole), Phalanges (toes)

  
• Skeletal System


  Parts include: Bones (skeleton), Joints, Cartilages, Ligaments

  
• Arches of the foot


  Two longitudinal arches, one transverse arch