Bone Classifications

• Skeletal Divisions


  there r 206 bones in the human skeleton = divided into 2 divisions

  = axial + appendicular skeletons
• Axial Skeleton


  axial skeleton forms the long axis of the body

  inc the bones of the skull

  vertebral column

  rib cage

  these bones protect, support or carry other body parts
• Appendicualr Skeleton


  appendicular skeleton consists of the bones of the upper + lower limbs + the girdles (shoulder bones + hip bones) that attach the limbs to the axial skeleton

  bones of the limbs help us move from place to place (locomotion) + manipulate our enviro
• Axial & Appendicular Skeleton


  long axis vs additional limbs

  
• Bones Classification


  long bones

  short bones

  sesamoid bones

  flat bones

  irregular bones

  
• Long Bones


  long bones r sonsiderably onger than they r wide

  has a diaphysis (shaft) + 2 epiphyses (ends)

  all limb bones except the patella, wrist + ankle bones r long bones

  these bones r named for their elongated shape, not their overall size

  the three bones in each of the fingers = long bones
• Short Bones


  short bones = roughly cube shaped

  E.g. Inc the 8 carpal bones of the hands that allow movement of the wrist + the tarsal bones of the feet that allow movement of the foot

  
• Sesamoid Bones


  special type of short bone that form in a tendon

  e.g. the patella

  they vary in size in diff individuals

  some sesamoid bones act to alter the direction of pull of a tendon

  others reduce friction + modify pressure on tendons to reduce abrasion/tearing

  
• Flat Bones


  flat bones = thin, flattened, + usually a bit curved

  the sternum, scapulae, ribs + most cranial bones of the skull = flat bones
• Irregular Bones


  irregular bones have complicated shapes that fit none of the preceding classes

  e.g. inc the vertebrae + the hip bones