Skeletal System - Ana Lab

• Adult skeleton have 206 bones and divided into five categories based on shapes
• Bone Type

  1. Long
  2. Short
  3. Flat
  4. Irregular
  5. Sesamoid
• Long bones

  • cylinder-like shape, longer than it is wide
  • for leverage
  • found in femur, tibia, fibula, metatarsals, humerus, ulna, radius, metacarpals, and phalanges
• short bones

  • cube-like shape, approximately equal in length, width and thickness
  • provide stability, support, while allowing for some motion
  • found in carpals, and tarsals
• flat bones

  • thin and curved
  • for points of attachment for muscles and protectors of internal organs
  • found in sternum, ribs, scapulae, and cranial bones
• irregular bones

  • complex shape
  • protect internal organs
  • found in vertebrae, and facial bones
• sesamoid bones

  • small and round which are embedded in tendons
  • protect tendons from compressive forces
  • found in patellae
• Division of Skeletal System

  1. Axial
  2. Appendicular
• Axial skeleton are made up of 80 bones while the appendicular is composed of 126
• Compact bone - dense, stronger of the two types of bone tissue which can be found under the periosteum and in the diaphyses of long bones
• spongy/cancellous bone - contains osteocytes housed in lacunae, but they are not arranged in concentric circles, instead, the lacunae and osteocytes are found in a lattice-like network of matrix spikes called trabecula
• Axial came from the word axis, which refers to how the bones of the axial skeleton are located along the central axis of the body
• True ribs are ranged from Rib 1 to 7 which are attached to the sternum with costal cartilage
• False ribs are ranged to Rib 8 to 10 which lacks sternal attachment but connect to the costal cartilage of Rib 7
• Floating ribs are Rib 11 and 12 that has no anterior attachment, as they are called floating
• appendicular skeleton is involved in locomotion and manipulation of objects
• axial skeleton functions to support and protect the organs of the dorsal and ventral cavities and serves as a surface for the attachment of muscles and parts of the appendicular skeleton