Lecture 6

1. Lecture 6 Skeletal System:Axial Skeleton

2. The Complete Skeleton • Axial skeleton • Skull • Hyoid bone • Vertebral column • Thoracic (rib) cage • Appendicular skeleton • Limbs • Girdles Fig. 7.1

3. Superior and Posterior Views of Skull or Cranium • External occipitalprotuberance • Ligamentum nuchae: Helps keep head erect • Nuchal lines: Neck muscle attachment Fig. 7.5

4. Lateral View of Skull • Temporal lines (temporalis muscle) • Mandible • Condyle • Coronoid process for temporalis muscle Fig. 7.6

5. Frontal View of Skull Frontal bone Parietal bone Temporal bone Sphenoid bone Ethmoid bone Nasal bone Lacrimal bone Perpendicular plate of ethmoid bone Zygomatic bone Vomer Inferior nasal concha Maxilla Mandible Fig. 7.4 • Optic foramen (optic nerve) • Lacrimal groove (tears from eye to nasal capsule)

6. Inferior View of Skull Maxilla Hard palate Palatine bone Temporal process of zygomatic bone Zygomatic arch Zygomatic process of temporal bone • Foramen magnum • Occipital condyles • Jugular foramen, carotid canal • Hard palate - maxilla and palatine Vomer Sphenoid bone Styloid process Mandibular fossa Temporal bone Jugular foramen Mastoid process Occipital condyle Carotid canal Foramen magnum Occipital bone External occipital crest Inferior nuchal line Superior nuchal line External occipital protuberance Fig. 7.8 Fig. 7.8

7. Hyoid Bone and Auditory Ossicles • Hyoid bone • Unpaired • No direct bony attachment to skull • Attachment point for some tongue muscles • Attachment point for neck muscles that elevate larynx during speech and swallowing • Auditory ossicles • Malleus, incus and stapes Fig. 7.26

8. Vertebra • Parts • Body • Vertebral foramen • Vertebral arch • Superior and inferior articular processes • Transverse process • Articular facets for rib • Spinous process Fig. 7.29

9. Vertebral Column • Regions • Cervical (7 vertebrae) • Thoracic (12 vertebrae) • Lumbar (5 vertebrae) • Sacral bone (1) • Coccygeal bone (1) Fig. 7.28

10. Cervical Vertebrae • Atlas • First vertebra • ‘yes’ motion • Axis • Second vertebra • Dens or odontoid process • ‘no’ motion Fig. 7.30

11. Thoracic and Lumbar Vertebrae Table 7.5 Table 7.5

12. Sacrum and Coccyx Fig. 7.31

13. Review Question The spinal cord passes along the vertebral column through the _______ and enters the skull through the __________. Spinous process, mandibular fossa Body, occipital condyles Superior and inferior articular processes, jugular foramen Vertebral arch, carotid canal None of the above is correct

14. Thoracic Cage and Sternum • Parts • Thoracic vertebrae • Ribs (12 pair) • True • False • Sternum (manubrium, body) Fig. 7.32

15. Points to Remember • Two major components of the human skeleton: • Axial skeleton arranged along the medial axis • Appendicular skeleton connects to the axial skeleton • Skull consists of: • 22 bones (single and paired) • 6 auditory ossicles (3 each side) and 1 hyoid • Vertebral column consists of: • Cervicals (7) • Thoracics (12) • Lumbars (5) • Sacrum (5, fused) • Coccyx (3-5, fused) • Rib cage has true (bone) ribs and false (cartilage) ribs

16. Questions?