1. Ch 5 Skeletal System
The Axial Skeleton

2. Do Now: What is the difference between a projection and a depression?
What is something interesting you have learned about the skeletal system so far?

3. The Axial Skeleton Forms the longitudinal part of the body
Divided into three parts
Skull
Vertebral column
Bony thorax (Ribs)

4. The Axial Skeleton
Figure 5.6

5. The Skull Two sets of bones Bones are joined by sutures
Cranium
Facial bones
Bones are joined by sutures
Only the mandible is attached by a freely movable joint

6. Cranium Frontal bone Parietal bone Temporal bones
Composed of eight large flat bones, all single, except for two paired bones (parietal and temporal)
Frontal bone
Forms the forehead, under the eyebrows, and the superior part of each eye’s orbit
Parietal bone
Paired bones that form the most superior and lateral walls of the cranium
Temporal bones
Inferior to the parietal bones

7. Cranium Occipital bone Sphenoid bone Ethmoid bone
Most posterior bone of the cranium. Forms the floor and back wall of the skull
In the base of this bone, is the foramen magnum, a large opening that allows the brain to connect to the spinal cord
Sphenoid bone
Goes the width of the skull and forms part of the floor of the cranial cavity
Ethmoid bone
Anterior to the sphenoid and forms the roof of the nasal cavity and part of the medial walls of the orbits(eyes)

8. The immovable joints of the skull
Sutures
Figure 7–3a, b

9. Sutures - Four Major Ones
Lambdoid suture – separates occipital from parietal
Coronal suture – attaches frontal to parietal
Sagittal suture – between parietal bones
Squamous suture – between temporal and parietal

10. Facial Bones
Fourteen bones compose the face. Twelve paired, only the mandible and vomer are single

11. Facial Bones Maxillae or maxillary bones Fuse to form the upper jaw
All facial bones, except the mandible join the maxillae
Palatine bones
Paired bones that form the posterior part of the hard palate
Zygomatic bones
Cheekbones
Also form parts of the lateral walls of the eye orbit
Lacrimal bones
Form the medial walls of each orbit
Serves as a passageway for tears

12. Form the bridge of the nose Vomer bone Single bone
Nasal bones
Form the bridge of the nose
Vomer bone
Single bone
Forms the nasal septum
Inferior conchae
Thin curved bones projecting from the lateral walls of the nasal cavity
Mandible
Lower jaw
Largest and strongest bone of the face
Joins the temporal bones on each side of the face
Forming the only freely movable joint in the skull

13. The Skull

14. Bones of the Skull

15. Human Skull, Superior View

16. Human Skull, Inferior View

17. Paranasal Sinuses
Hollow portions of bones surrounding the nasal cavity
Figure 5.10

18. Paranasal Sinuses Functions of paranasal sinuses Lighten the skull
Give resonance and amplification to voice
Figure 5.10

19. The Hyoid Bone Serves as a moveable base for the tongue
The only bone that does not articulate with another bone
It is suspended in the midneck region above the larynx
Figure 5.12

20. The Fetal Skull
The fetal skull is large compared to the infants total body length
Figure 5.13

21. The Fetal Skull
Fontanelles – fibrous membranes connecting the cranial bones
Allow the brain to grow
Convert to bone within 24 months after birth
Figure 5.13

22. Axial Bones

23. Assignment Ch5 WS Pg3-4 Cranial and Facial Bones Matching
Skull Labeling Diagram
Due in twenty minutes

24. The Vertebral Column

25. The Vertebral Column
Spine extends from the skull, which it supports, to the pelvis, where it transmits the weight of the body to the lower limbs

26. It is formed of 26 irregular bones connected by ligaments
The Vertebral Column
It is formed of 26 irregular bones connected by ligaments
The spine has a normal curvature

27. Region Name Specific Vertebrae
The Vertebral Column
Each vertebrae is given a name according to its location
Region Name Specific Vertebrae
Cervical C1-C7
Atlas C1
Axis C2
Thoracic T1-T12
Lumbar L1-L5
Sacrum Fused
Coccyx Fused

28. The Vertebral Column Vertebrae separated by intervertebral discs
Intervertebral discs cushion and absorb shock between the vertebrae
As a person ages, they are susceptible to herniated discs (slipped)

29. Vertebrae
7 cervical
12 thoracic
5 lumbar
sacrum
coccyx

30. Vertebral Column
Figure 5.14

31. Form of the vertebral column
Cervical vertebrae (C1 – C7)
Forms the neck
C1 – the atlas, allows you to nod “yes”
C2 – the axis, allows for the rotation and you to move from side to side to say “no”
C3-C7 – smallest and lightest vertebrae

32. Form of the vertebral column
Thoracic vertebrae (T1-T12)
Lumbar vertebrae (L1-L5)
Sacrum -- heartshaped
Formed by the fusion of five vertebrae
Forms the posterior wall of the pelvis
Articulates with the sacroiliac joints
Coccyx
Formed by the fusion of three to five small irregularly shaped vertebrae
Tailbone

33. Structure of a Typical Vertebrae
Figure 5.16

34. Regional Characteristics of Vertebrae
Figure 5.17a–b

35. Regional Characteristics of Vertebrae
Figure 5.17c–d

36. Curvature of the spine
The disks and S-shaped structure of the vertebral column work to prevent shock
Primary curvatures – curvatures of the thoracic and sacral regions and are present at birth
Secondary curvatures – cervical curvature develops as a baby raises their head, and lumbar curvature develops as a baby begins to walk

37. Abnormal curvature of the spine
May be present at birth or result from disease or poor posture
Scoliosis – medial or lateral (right or left) curve
Kyphosis – curve at the superior or thoracic part of the spine
Lordosis – curve at the inferior or lumbar part of the spine

39. Scoliosis

40. Lordosis

41. Assignment for Part 2 Skeletal WS Pg5-6 Paranasal Sinuses
Vertebral Column
Spine Labeling Diagram

42. The Bony Thorax Forms a cage to protect major organs
Made-up of three parts
Sternum
Ribs
Thoracic vertebrae
Figure 5.19a

43. Sternum – breastbone
Flat bone and the result of the fusion of three bones:
Manubrium
Body
Xiphoid process
It attaches to the first 7 ribs

44. Ribs 12 pairs of ribs forms the walls of the thoracic cage
True ribs – first 7 pairs of ribs attach directly to the sternum by costal cartilages
False ribs – next 5 pairs, either attach indirectly to the sternum or are not attached to the sternum at all
Floating ribs – last two pairs of false ribs lack the sternal attachments
Intercostal spaces are filled with intercostals muscles that aid in breathing

45. Axial Skeleton Video
05 Human Body Skeletal System
5:09-7:42

46. Ch5 Ws Pg6 Ribs Labeling Diagram
Assignment
Ch5 Ws Pg6
Ribs Labeling Diagram