Anatomy L3

• axial skeleton: down midline, axis, rib cage, skull, hyoid bone, vertebral column
• appendicular skeleton: shoulder, arm, hand, pelvic, leg, foot
• Functions of skeletal system

  • support and structure
  • storage of minerals
  • blood cell production (in bone marrow)
  • leverage- for movement
  • protection (of organs)
• Osseous tissue: supporting connective tissue

  • matrix of bone consists of calcium phosphate (2/3 of bone mass)
  • collagen fibers- 1/3 of bone mass, resist tension
  • bone cells- 2% of bone mass
• osteocytes

  mature bone cells
• osteoblasts

  immature bone cells that become mature
• osteoprogenitor cells- bone stem cells (for repair)
• osteoclasts- dissolve (break down bone cells)- osteolysis
• central canal- contains small veins
• articular surface- where to connect w/ another bone
• cortex- compact bone
• flat bones- red bone marrow
• long bones shaft- yellow bone marrow- WBC made

  ends of long bones- red bone marrow
• no osteons in spongy bones
• spongy bones

  • resists stresses applied from many different directions
  • lighter
  • support and protect
• compact bone

  • conducts stress from 1 end of the long bone to the other end of the long bone
• periosteum

  • outer surface of bone; fibrous and osteogenic layers
• endosteum

  inner surface of bone
• epiphyseal- cells multiply and grow
• medullary cavity- red bone marrow
• sutural bones

  • skull and cranium
  • small, flat, along sutures, not always present
• pneumatized bones

  • hollow w/ air pockets
  • btwn eye sockets
• flat bones

  • flat, spongy bone sandwich
  • diploe- spongy bone
  • skull, sternum, ribs, scapulae
  • protect tissues underneath
• long bones

  • diaphysis, two metaphyses, medullary (marrow) cavity
• sesamoid bones

  • small, round, flat
  • near joints
• short bones

  • tarsal- 7, carpal- 8
  • boxlike appearance
• irregular bones

  • complex shapes w/ short, flat, notched, ridged surfaces
• Joints (articulations)

  • junctions btwn two or more bones
  • bones may be in direct contact or separated by: fibrous tissue, cartilage, or fluid
• Synarthrosis (immovable joint)

  • suture( face)
  • synchondrosis (rib w/ sternum
  • gomphosis (teeth w/ jaw)
  • synostosis( frontal bone fusion)
• amphiarthrosis (slightly movable joints)

  • syndesmosis (radius and ulna, tibia and fibula)
  • symphysis ( pelvic bones join)
• diarthroses (freely movable synovial joints)

  • synovial
• freely movable synovial joints

  • joint capsule
  • articular cartilage
  • joint cavity filled w/ synovial fluid
  • synovial membrane
  • accessory structures
  • sensory nerves
  • blood vessels
• dislocations- displacement of articulary bones
• strength vs mobility

  • highly mobile joint isn't stable - diarthrosis
  • fair immovable joint is stable - synarthrosis
  • limited mobility reduces chance of injury
• abduction- moving away from body
• adduction- moving toward body

  shoulder, hip, wrist
• flexion- decreases angle btwn bones of joint
• extension- increases angle between bones of joint
• hyperextension- extending beyond normal limits; ligaments are loose
• circumduction- making a circular motion, hip, fingers