1. The Skeleton
Part A 7

2. The Axial Skeleton Eighty bones segregated into three regions Skull
Vertebral column
Bony thorax

3. The Skull The skull Cranium Facial bones Eight cranial bones –
2 parietal, 2 temporal, frontal, occipital, sphenoid, and ethmoid
Facial bones
Fourteen bones
2 maxillae, 2 zygomatics, 2 nasals, 2 lacrimals, 2 palatines, and 2 inferior conchae
mandible and vomer are unpaired

4. Skull: Anterior View
Figure 7.2a

5. Skull: Lateral View
Figure 7.3a

6. Skull: Posterior View
Figure 7.2b

7. Inferior Portion of the Skull
Figure 7.4a

8. Paranasal Sinuses
Figure 7.11

9. Vertebral Column 26 irregular bones 7 Cervical vertebrae
12 Thoracic vertebrae
5 Lumbar vertebrae
Sacrum – 5 fused bones
Coccyx – 4 fused bones

10. Vertebral Column: Ligaments
Anterior (ventral) and posterior (dorsal) longitudinal ligaments
Short ligaments connect adjoining vertebrae together

11. General Structure of Vertebrae
Figure 7.15

12. Vertebral Column: Intervertebral Discs
Nucleus pulposus – inner gelatinous region
Annulus fibrosus – collar of collagen and fibrocartilage

13. Cervical Vertebrae: The Atlas (C1)
Figure 7.16a, b

14. Cervical Vertebrae: The Axis (C2)
Figure 7.16c

15. Cervical Vertebrae
Figure 7.17a

16. Sacrum and Coccyx: Posterior (dorsal) View
Figure 7.18b

17. Thorax (Thoracic Cage)
The thoracic cage
Dorsal - thoracic vertebrae
Laterally - ribs
Ventral - sternum and costal cartilages
Functions
Protective cage around the heart, lungs, and great blood vessels
Supports the pectoral girdle and upper limbs
Attachment sites for neck, back, chest, and shoulder muscles
Intercostal muscles lift and depress the thorax for breathing

18. Thorax: Sternum Fusion of three bones manubrium, sternal body,
xiphoid process

19. Thorax: Ribs 12 pairs All attached dorsally to the thoracic vertebrae
Vertebrosternal ribs –attach to sternum via costal cartilages – “true ribs”
Vertebrochondral ribs - attach to costal cartilage of rib 7 – “false ribs”
Vertebral ribs - no ventral attachment – “floating ribs”

20. Pectoral Girdle (Shoulders)
Figure 7.22a

21. Scapulae (Shoulder Blades)
Figure 7.22d, e

22. The Upper Limb
The proximal arm (brachium), distal arm (forearm; antebrachium), and hand (manus)
Thirty-seven bones

23. Humerus of the Proximal Arm
Figure 7.23

24. Radia and Ulna of the Distal Arm (Forearm)
Figure 7.24

25. Manus (Hand) 14 5 8
Figure 7.26a

26. Pelvic Girdle (Hips) Os coxae - coxal bones
Coxal bone is fusion of 3 bones – ilium, ischium, pubis
Os coxae, sacrum and coccyx, form the bony pelvis

27. Os coxa: Lateral View
Obturator foramen

28. Comparison of Male and Female Pelvic Structure
Female pelvis
Tilted forward, adapted for childbearing
Pubic arch obtuse angle
Cavity of the true pelvis is broad, shallow,
Male pelvis
Less tilted forward
Pubic arch acute angle
Cavity of true pelvis is narrow and deep

29. The Lower Limb
the thigh (proximal), leg (distal), and foot

30. Femur
Figure 7.28b

31. Tibia and Fibula
Figure 7.29

32. Foot 14 5 7
Figure 7.31b, c

33. Developmental Aspects: Fetal Skull
At birth, fetal skull bones are incomplete and connected by fontanels
Fontanels
Unossified remnants of fibrous membranes between bones
anterior,
posterior
mastoid
sphenoid
Figure 7.33

34. Developmental Aspects: Growth Rates
At birth, the cranium is huge relative to the face
Mandible and maxilla are foreshortened but lengthen with age
The arms and legs grow at a faster rate than the head and trunk, leading to adult proportions
Figure 7.34