Divisions of the skeleton

Cards (26)

  • What are the 2 divisions of the skeleton?
    1. Axial
    2. Appendicular
  • The axial skeleton is made up of the skull, vertebral column, ribcage, sternum, hyoid bone. They also protect the vital organs.
  • The skull is part of the superior part of the body, which contains the cranium and facial bones.
  • The cranium encloses the brain, which allows the facial bones to attach.
  • The facial bones protect and support facial organs.
  • The verterbral column is part of the axial skeleton, whcih allows the person to stand up right.
    • contains ligaments and muscle movements
    • supports the head
    • have 4 divisions: cervical, lumbar, thoracic, saccrum
  • The ribcage contains the sternum and ribs. This is to protect the front.
    • ribs contain 12 on each side and joins onto the sternum, which are the top 10 ribs that attach to the cartilage.
  • The appendicular skeleton is the skeleton of the upper and lower limbs.
  • The structure of the limbs contain:
    • single, large, long bone, which is the humerus and femur
    • has 2 distal bones, which are long and thinner
  • The ulna and radius are superior, mobile and weight bearing.
  • The tibia and fibula are inferior, immobile and non-weight bearing.
  • Bipedalism is the ability to walk on two legs using 2 limbs, which are the upper limb and lower limb.
  • The upper limb in bipedalism does not need stability because it is adapted to manipulated objects and precise movements.
  • The lower limb needs more stability due to its role as a support base when walking or running.
  • The hands do not need stability because it is not involved with locomotion.
    Structure of hands:
    • Carpals (8) - short bones
    • Metacarpals (5) - long bones
    • Phalanges (14) - 2 in thumb
  • The humerus is lighter and is not responsible for long strides and for not taking weight as it is not stable, therefore less articulation.
  • The femur is more deeper in articulation and is for long strides and more stable.
  • Pronation and supernation occur when we move our forearms and wrists. They have a wide surface area to move the wrist, which allows for rotation.
  • Supination occurs when the palm faces upwards while pronation occurs when the palm faces downwards.
  • The ankle joint is stable, the tibia is robust (weight bearing).
  • The limbs attach to the axial skeleton by the pectoral girdle, which contains the clavicle and scapula.
  • The clavicle stabilises for the shoulder blade as it keeps it in the right position.
  • The Scapula is free moving and does the muscle attachment and joins the upper limb.
  • The lower limb also attaches using the pelvic girdle, containing the hip bone, saccrum and are weight bearing.
  • The hip bone contains:
    • illium
    • pubis
    • ischium
    And fuse together to form the hip bone.
  • Female pelvis is bigger because they have potential to make birth and maximise their space for that.
    • more circular
    • outlet is more open