Axial skeleton parts 3 5


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Axial skeleton parts 3 5

  1. 1. Organization of the Skeleton <ul><li>Axial Skeleton </li></ul><ul><li>Appendicular Skeleton </li></ul>Axial Skeleton is the “ blue ” Appendicular Skeleton is the “ purple ”
  2. 2. Ossicles of the Ear The ossicles are the bones of the middle ear and are often simply called “the ear bones.” The ossicles function to turn sound into mechanical vibrations which the human nervous system can interpret. Skull Subdivision Three
  3. 3. <ul><li>Each ear has three ossicles: </li></ul><ul><li>The Malleus (2) – a.k.a. as the “hammer” </li></ul><ul><li>The Incus (2) – a.k.a. as the “anvil” </li></ul><ul><li>The Stapes (2) – a.k.a. as the “stirrup” </li></ul>Malleus Incus Stapes
  4. 4. Skull Subdivision Four Hyoid Bone This bone is located beneath the mandible and serves to support the tongue and to provide an attachment surface for many of the muscles that control the tongue and function in swallowing.
  5. 5. The number of wormian bones varies from person to person. They are extra bones that develop in the sutures of the cranium. Skull Subdivision Five Wormian bones
  6. 6. Summary of the Skull <ul><ul><ul><li>2. Face (14) </li></ul></ul></ul><ul><ul><ul><ul><li>Nasal (2) </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Zygomatic (2) </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Maxilla (2) </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Mandible (1) </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Lacrimal (2) </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Palatine (2) </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Inferior nasal conchae (2) </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Vomer (1) </li></ul></ul></ul></ul><ul><ul><ul><li>3. Hyoid (1) </li></ul></ul></ul><ul><ul><ul><li>4. Ossicles (6) </li></ul></ul></ul><ul><ul><ul><li>5. Wormian (?) </li></ul></ul></ul><ul><li>Axial Skeleton </li></ul><ul><ul><li>Skull (29) </li></ul></ul><ul><ul><ul><li>Cranium (8) </li></ul></ul></ul><ul><ul><ul><ul><li>Frontal (1) </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Parietal (2) </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Occipital (1) </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Temporal (2) </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Sphenoid (1) </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Ethmoid (1) </li></ul></ul></ul></ul>
  7. 7. <ul><li>The Vertebral Column </li></ul><ul><li>Also called the spinal column , “spine,” or “backbone,” the vertebral column consists of 26 bones in an adult, but has 33 in an infant. It is a complex structure made from alternating bone and cartilage, subdivided into five regions or “curvatures,” and responsible for many important functions. </li></ul>Part Two Lateral View Posterior View
  8. 8. Subdivisions of the Vertebral Column <ul><li>1. Cervical Curvature – the “neck” </li></ul><ul><li>Seven (7) cervical vertebrae </li></ul><ul><li>Thoracic Curvature – “the middle-back” </li></ul><ul><li>Twelve (12) thoracic vertebrae </li></ul><ul><li>3. Lumbar Curvature – “the “lower back” </li></ul><ul><li>F ive (5) lumbar vertebrae </li></ul><ul><li>4. Sacral Curvature – “small of the back” </li></ul><ul><li>The Sacrum – five fused vertebrae </li></ul><ul><li>5. Coccygeal Curvature – the “tailbone” </li></ul><ul><li>The Coccyx – four fused, immature vertebrae </li></ul>
  9. 9. Functions of the Vertebral Column: <ul><li>Forms a tube which houses and protects the spinal cord </li></ul><ul><li>Provides protective channels for the lower spinal nerves </li></ul><ul><li>Supports the weight of the body and head </li></ul>Cervical Vertebrae Thoracic Vertebrae Lumbar Vertebrae Sacrum Coccyx
  10. 10. Functions Continued: <ul><li>Intervertebral discs provide “ shock absorber ” action cushioning the forces created by movement </li></ul><ul><li>Provides posterior attachment sites for the ribs </li></ul><ul><li>Provides important attachment sites for many muscles of the back </li></ul>C 1 – C 7 T 1 – T 12 L 1 – L 5 Cervical Vertebrae Thoracic Vertebrae Lumbar Vertebrae Sacrum Coccyx
  11. 11. Summary of the Vertebral Column <ul><li>Bones of the Vertebral Column </li></ul><ul><li>Cervical Vertebrae (7) </li></ul><ul><li>Thoracic Vertebrae (12) </li></ul><ul><li>Lumbar Vertebrae (5) </li></ul><ul><li>Sacrum (1) </li></ul><ul><li>Coccyx (1) </li></ul>
  12. 12. <ul><li>Thoracic Cage </li></ul><ul><li>Sometimes misnamed the “ribcage,” the thoracic cage is composed of 37 bones, fibrous cartilage discs and specialized hyaline cartilage. </li></ul>Part Three
  13. 13. <ul><li>To support and protect the soft, vital organs of the thoracic cavity </li></ul><ul><li>Provide support for the bones of the pectoral girdle and upper extremities </li></ul><ul><li>Plays an important role in breathing </li></ul>Functions of the Thoracic Cage: The bones of the thoracic cage are as follows:
  14. 14. The Sternum <ul><li>Sometimes called the “breastbone,” the sternum is a “dagger-shaped” bone that forms a solid plate of armor down the middle of the chest, thus protecting the heart . It articulates with the clavicles, and is also a very important site for blood cell production throughout life. The sternum is divided into three parts: </li></ul>
  15. 15. <ul><li>The manubrium </li></ul><ul><li>The body or gladiolus </li></ul><ul><li>The xiphoid process – made of hyaline cartilage. </li></ul>
  16. 16. <ul><li>The Costal Cartilage </li></ul><ul><li>Composed of hyaline cartilage, the costal cartilage attaches, either directly or indirectly, the first ten pairs of ribs to the sternum. This cartilage also gives the thoracic cage its characteristic flexibility, which is important to the mechanism of breathing. </li></ul>
  17. 17. <ul><li>3. The Ribs – Both males and females have twelve (12) pairs of ribs. All of these articulate posteriorly with the thoracic vertebrae. The ribs are further subdivided on the basis of how they do or do not connect with the sternum via the costal cartilage as follows: </li></ul>
  18. 18. <ul><li>a. True ribs – These are the first seven (7) pairs of ribs. These can be distinguished on the basis that they are attached directly to the sternum via the costal cartilage. </li></ul>
  19. 19. <ul><li>b. False ribs – These are the last five (5) pairs of ribs. </li></ul><ul><li>1. The 8 th , 9 th , and 10 th pairs are indirectly attached to the sternum via the costal cartilage. </li></ul><ul><li>2. The 11 th and 12 th pairs are not attached to the sternum at all. These two pairs are often referred to as floating ribs . </li></ul>
  20. 20. <ul><li>The Thoracic Vertebrae </li></ul><ul><li>Though these are actually a part of the vertebral column , they also serve as the posterior anchor for the ribs and function as a solid posterior wall for the entire thoracic cage structure. </li></ul>