MLSHAPPC: Skeletal System

• Skeletal system consists of

  • Bones
  • Joints
  • Cartilages
  • Ligaments
• Axial Skeleton


  One of the two divisions of the skeletal system
• Appendicular Skeleton


  One of the two divisions of the skeletal system
• Bones

  • Support the body, protect soft organs, provide locomotion due to attached muscles, store minerals and fats, and form blood cells
• The adult skeleton consists of 206 bones
• Two basic types of bone tissue

  • Compact bone
  • Spongy bone
• Compact bones


  Denser, smoother and homogeneous
• Spongy bones


  Open with small and irregular adjacent cavities
• Classification of Bones on the Basis of Shape

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


  • Longer than wide and contains compact bones (e.g. femur, humerus)
• Short Bones

  • Cube shape and contains spongy bones (e.g. carpals)
• Flat Bones


  • Thin, flattened, and usually curved. Contains a layer of compact bones on spongy bones (e.g. skull)
• Irregular Bones


  • Irregular shapes, and do not fit into other bone categories (e.g. vertebrae)
• Structures of Long Bones

  • Diaphysis
  • Epiphysis
  • Periosteum
  • Sharpey's fibers
  • Arteries
  • Articular Cartilage
  • Medullary Cavity
• Diaphysis


  Shaft (middle) and composed of compact bones
• Epiphysis


  Ends of the bone, composed of spongy bones
• Periosteum


  Outside covering of diaphysis and consists of fibrous connective membrane
• Sharpey's fibers


  Secure periosteum to underlying bone
• Articular Cartilage


  Covers the external surface of the epiphyses. It is made of hyaline cartilage and it decreases friction at joint surfaces.
• Medullary Cavity


  Cavity of the shaft which contains yellow marrow (mostly fat) in adults and red marrow (for blood cell formation) in infants
• Categories of bone markings

  • Projection and Processes
  • Depression or cavities
• Projection and Processes

  Grow out from the bone surface
• Change in human skeleton

  1. In embryos, the skeleton is primarily hyaline cartilage

  2. During development, this cartilage is replaced by bone

  3. Cartilages remains in isolated areas (bridge of the nose, parts of ribs, joint)
• Bone Growth

  1. Epiphyseal plates allow for growth of long bone during childhood

  2. New cartilage is continuously formed

  3. Older cartilage becomes ossified (ossification)

  4. Cartilage is broken down

  5. Bones are remodeled and lengthened until growth stops
• Types of Bone cells

  • Osteocytes
  • Osteoblast
  • Osteoclast
• Osteocytes


  Mature bone cell
• Osteoblast


  Bone-forming cell, producing new tissues by using collagen
• Osteoclast


  Bone destroying cells, break down matrix for remodeling and release of calcium
• Types of Bone Fractures

  • Closed (simple) fracture
  • Open (compound) fracture
• Common Types of Fractures

  • Comminuted
  • Compression
  • Depressed
  • Impacted
  • Spiral
  • Greenstick
• Repair of Bone Fractures

  1. Hematoma Formation

  2. Fibrocartilage formation

  3. Bone callus formation

  4. Bone Remodeling
• Parts of the Axial Skeleton

  • Skull
  • Vertebral column
  • Thorax
• Skull

  Its bones are joined together by suture. Only the mandible is attached by a freely movable joint. It consists if two sets of bones: Cranium and Facial bones
• Paranasal Sinuses


  Hollow portion of bones surrounding the nasal cavity. It lighten the skull and give resonance and amplification to voice
• Hyoid Bone

  Only bone that does not articulate (move) with another bone. Only bone in the body that is not connected with other bones. Serves as a movable base for the tongue
• Fetal Skull


  Large compared to the infants total body length. It gives space in our brain. Fontanelles (bumbunan) - fibrous membranes connecting the cranial bones. Allows the brain to grow. Convert to bone within 24 months
• Vertebral Column

  Vertebrae separated by intervertebral discs. The spine has normal curvature. Each vertebrae is given a name according to its location
• Bony Thorax


  Often called the thoracic cage; forms a cage to protect major organs. Consists of sternum, ribs, and thoracic vertebrae
• Parts of the Appendicular Skeleton

  • Pectoral girdle
  • Upper limbs
  • Pelvic girdle
  • Lower limbs
• Pectoral (Shoulder) girdle


  Allows upper limbs to have free movement. Consists of clavicle and scapula