1 Chapter 7 The Skeletal System: The Axial Skeleton

7-2 Skeletal System Gross Anatomy Chapter 7

7-3 Skeletal System Provides framework Without skeleton, muscles couldn’t move body Components –Bones –Cartilage –Ligaments –Tendons Relationships among bones and soft tissues

7-4 Skeleton Axial skeleton –Skull –Hyoid bone –Vertebral column –Thoracic (rib) cage Appendicular skeleton –Limbs –Girdles

7-5 The Complete Skeleton

7-6 Anatomic Bone Features Terms –Body: Main part –Head: Enlarge end –Neck: Constriction between head and body –Margin or border: Edge –Angle: Bend –Ramus: Branch off body –Condyle: Smooth rounded articular surface –Facet: Small flattened articular surface Projections –Process: Prominent projection –Tubercle: Small rounded bump –Tuberosity: Knob –Trochanter: Tuberosities on proximal femur –Epicondyle: Near or above condyle

7-7 Anatomic Bone Features Ridges –Line or linea: Low ridge –Crest or crista: Prominent ridge –Spine: Very high ridge Openings –Foramen: Hole –Canal or meatus: Tunnel –Fissure: Cleft –Sinus or Labyrinth: Cavity Depressions –Fossa: General term for a depression –Notch: Depression in bone margin –Fovea: Little pit –Groove or sulcus: Deeper, narrow depression

7-8 The Skull or Cranium Functions –Protects brain –Supports organs of special senses –Provides foundation for structures that take air, food, water into body Superior view of skull –Parietal bones –Frontal bone –Sagittal suture –Coronal suture

7-9 Posterior View of Skull Occipital bone Lambdoid suture Sutural bones External occipital protuberance –Ligamentum nuchae: Helps keep head erect –Nuchal lines: Neck muscle attachment points

7-10 Lateral View of Skull Squamous suture External auditory meatus Mastoid Process Temporal lines Sphenoid bone Zygomatic bones Maxilla Mandible

7-11 Frontal View of Skull Frontal bone Zygomatic bones Maxillae Mandible Orbits –Nasolacrimal canal –Optic foramen

7-12 Bones of Nasal Cavity

7-13 Paranasal Sinuses Functions –Decrease skull weight –Resonating chambers Names –Frontal –Maxillary –Ethmoidal –Sphenoidal

7-14 Inferior View of Skull Foramen magnum Occipital condyles Jugular foramina Styloid processes Vomer bone Hard or bony palate

7-15 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

7-16 Vertebral Column Supports weight of head and trunk Protects the spinal cord Allow spinal nerves to exit the spinal cord Provides site for muscle attachment Permits movement of head and trunk

7-17 Vertebra Body Vertebral foramen Vertebral arch Pedicle Lamina Transverse process Spinous process Articular processes

7-18 Intervertebral Disks Located between adjacent vertebrae Functions –Provide support –Prevent vertebrae rubbing Consist of –Annulus fibrosus –Nucleus pulposus

7-19 Herniated or Ruptured Disk

7-20 Spina Bifida

7-21 Vertebral Column Regions –Cervical (7 vertebrae) –Thoracic (12 vertebrae) –Lumbar (5 vertebrae) –Sacral bone (1) –Coccygeal bone (1) Major Curvatures (4) Abnormal curvatures –Lordosis –Kyphosis –Scoliosis

7-22 Cervical Vertebrae Atlas –First vertebra Axis –Second vertebra –Dens or odontoid process Vertebral prominens

7-23 Thoracic and Lumbar Vertebrae

7-24 Sacrum and Coccyx

7-25 Thoracic or Rib Cage Functions –Protects vital organs –Forms semi-rigid chamber for respiration Parts –Thoracic vertebrae –Ribs (12 pair) True or Vertebrosternal False or Vertebrochondral Floating or vertebral –Sternum

7-26 Sternum Breastbone Parts –Manubrium –Body –Xiphoid process Sternal angle –Important landmark for counting ribs to locate areas of the heart