1. SKELETAL SYSTEM
Chapter 7
7-1

2. Chapter 7 Skeletal System
Bone Classification
Long Bones
Short Bones
Flat Bones
Irregular Bones
Sesamoid Bones (round)
7-2

3. Bone Function Support and Protection gives shape to head, etc.
supports body’s weight
protects lungs, etc.
Blood Cell Formation
hematopoiesis
red marrow
Inorganic Salt Storage
calcium
phosphate
magnesium
sodium
potassium
Body Movement
interacts with muscles
bones act as rigid bar of a lever
7-12

4. Parts of a Long Bone epiphysis (end) diaphysis (shaft) compact bone
distal
proximal
diaphysis (shaft)
compact bone
spongy bone
articular cartilage
periosteum (outer covering)
endosteum (inner covering)
medullary cavity (central space)
marrow
red (hematopoiesis, make RBC’s)
yellow (fat storage)
7-3

5. Compact and Spongy Bone
7-4

6. Microscopic Structure of Compact Bone
osteon (cells grow in circle)
osteonic canal (canal for bv)
perforating canal (for bv)
osteocyte (bone cell)
lacuna (space)
bone matrix (collagen, salt)
canaliculus (connects cells)
7-5

7. Bone Development Intramembranous Ossification
bones originate within sheetlike layers of connective tissues
broad, flat bones
skull bones (except mandible)
Endochondral Ossification
bones begin as hyaline cartilage
most bones of the skeleton
7-6

8. Endochondral Ossification
hyaline cartilage model
primary ossification center
secondary ossification centers
epiphyseal plate
osteoblasts vs. osteoclasts
7-7

9. Growth at the Epiphyseal Plate
First layer of cells
closest to the end of epiphysis
resting cells
anchors epiphyseal plate to epiphysis
Second layer of cells
many rows of young cells
undergoing mitosis
7-8

10. Growth at the Epiphyseal Plate
Third layer of cells
older cells
left behind when new cells appear
cells enlarging and becoming calcified
Fourth layer of cells
thin
dead cells
calcified intercellular substance
7-9

11. Homeostasis of Bone Tissue
Bone Resorption – action of osteoclasts and parathyroid hormone
Bone Deposition – action of osteoblasts and calcitonin
7-10

12. Factors Affecting Bone Development, Growth, and Repair
Deficiency of Vitamin A – retards bone development
Deficiency of Vitamin C – results in fragile bones
Deficiency of Vitamin D – rickets, osteomalacia
Insufficient Growth Hormone – dwarfism
Excessive Growth Hormone – gigantism, acromegaly
Insufficient Thyroid Hormone – delays bone growth
Sex Hormones – promote bone formation; stimulate ossification of epiphyseal plates
Physical Stress – stimulates bone growth
7-11

13. Levers and Movement
7-14

14. Skeletal Organization
Axial Skeleton
head
neck
trunk
Appendicular Skeleton
upper limbs
lower limbs
pectoral girdle
pelvic girdle
7-15

15. Terms Used to Describe Skeletal Structures
See table 7.4 on page 202
These terms will be used to describe specific parts of a bone.
You will need to understand what many of them mean.

16. Hyoid (1)
Supports tongue
7-16

17. Skull Frontal (1) (orange) forehead roof of nasal cavity
roofs of orbits
frontal sinuses
supraorbital foramen
coronal suture
7-17

18. Skull Parietal (2) (blue) side walls of cranium roof of cranium
sagittal suture
between 2 parietal bones
7-18

19. Skull Temporal (2) (red) wall of cranium floor of cranium
floors and sides of orbits
squamosal suture
external acoustic meatus
mandibular fossa
mastoid process
styloid process
zygomatic process
7-19

20. Skull Occipital (1) (blue) back of skull base of cranium
foramen magnum
occipital condyles
lambdoidal suture
7-20

21. Skull Sphenoid (1) (purple) base of cranium sides of skull
floors and sides of orbits
sella turcica
sphenoidal sinuses
7-21

22. Skull Ethmoid (1) roof and walls of nasal cavity floor of cranium
wall of orbits
cribiform plates
perpendicular plate
superior and middle nasal conchae
Support mucous membranes
moisten and warm air
ethmoidal sinuses
crista gallis
7-22

23. Facial Skeleton Maxilla (2) (yellow) upper jaw anterior roof of mouth
floors of orbits
sides of nasal cavity
floors of nasal cavity
alveolar processes
maxillary sinuses
palatine process
7-23

24. Facial Skeleton Palatine (2) posterior roof of mouth
floor of nasal cavity
lateral walls of nasal cavity
7-24

25. Facial Skeleton Zygomatic (2) (Green) prominences of cheeks
lateral walls of orbits
floors of orbits
temporal process
7-25

26. Facial Skeleton Lacrimal (2) (blue) Nasal (2) (green)
medial walls of orbits
groove from orbit to nasal cavity
pathway for tears
Nasal (2) (green)
bridge of nose
7-26

27. Facial Skeleton Vomer (1) (fuscia) inferior portion of nasal septum
7-27

28. Facial Skeleton Inferior Nasal Conchae (2) (blue)
extend from lateral walls of nasal cavity
7-28

29. Facial Skeleton Mandible (1) lower jaw only mobile bone in skull body
ramus
mandibular condyle
coronoid process
alveolar process
mandibular foramen
mental foramen
7-29

30. Infantile Skull Fontanels – fibrous membranes (soft spot)
Fontanels close by:
Posterior – 2 mo
sphenoid – 3 mo
Mastoid – end 1st yr
Anterior – end 2nd yr
7-30

31. Vertebral Column cervical vertebrae (7) thoracic vertebrae (12)
lumbar vertebrae (5)
sacrum (1; 5 fused)
coccyx (1; 4 fused)
7-31

32. Vertebral Column cervical curvature thoracic curvature
lumbar curvature
pelvic curvature
rib facets
vertebra prominens
intervertebral discs
intervertebral foramina
7-32

33. Cervical Vertebrae (7) Atlas – 1st; supports head
Axis – 2nd; dens pivots to turn head
transverse foramina
bifid spinous processes
vertebral prominens – useful landmark on 7th
7-33

34. Thoracic Vertebrae (12)
long spinous processes
rib facets
7-34

35. Lumbar Vertebrae (5)
large bodies
thick, short spinous processes
7-35

36. Sacrum (1) five fused vertebrae (between 18 – 30 yrs)
median sacral crest
dorsal sacral foramina
posterior wall of pelvic girdle
sacral promontory
7-36

37. Coccyx (1)
tailbone
four fused vertebrae (by 25 yrs)
7-37

38. Thoracic Cage Ribs Sternum Thoracic vertebrae Costal cartilages
Supports shoulder girdle
Protects viscera
Role in breathing
7-38

39. Ribs (24) True ribs (7)[on each side] False ribs (5)[on each side]
floating (inferior 2) [on each side]
7-39

40. Rib Structure Shaft Head – posterior end; articulates with vertebrae
Tubercle – articulates with vertebrae
Costal cartilage – hyaline cartilage, connect rib to sternum
7-40

41. Sternum (1)
Manubrium
Body
Xiphoid process
7-41

42. Pectoral Girdle shoulder girdle clavicles (2) scapulae (2)
supports upper limbs
7-42

43. Clavicles (2) articulate with manubrium
articulate with scapulae (acromion process)
7-43

44. Scapulae (2) spine supraspinous fossa infraspinous fossa
acromion process
coracoid process
glenoid cavity
7-44

45. Upper Limb
Humerus
Radius
Ulna
Carpals
Metacarpals
Phalanges
7-45

46. Humerus (2) bone in upper arm head greater tubercle lesser tubercle
anatomical neck
surgical neck
deltoid tuberosity
capitulum (w/ radius)
trochlea (w/ ulna)
coronoid fossa
olecranon fossa
7-46

47. Radius (2) lateral forearm bone head allows rotation crosses over ulna
radial tuberosity
styloid process
7-47

48. Ulna (2) medial forearm bone trochlear notch olecranon process
coronoid process
styloid process
7-48

49. Wrist and Hand Carpals (16) [8 in each] Metacarpals (10) [5 in each]
trapezium
trapezoid
capitate
scaphoid
pisiform
triquetrum
hamate
lunate
Metacarpals (10) [5 in each]
Phalanges (28) [14 in each]
proximal phalanx
middle phalanx
distal phalanx
7-49

50. Pelvic Girdle Coxae (2) supports trunk of body protects viscera
Sacrum and Coccyx
sometimes considered part of girdle
7-50

51. Coxae (2) hip bones ilium ischium pubis obturator foramen acetabulum
iliac crest
iliac spines
greater sciatic notch
ischium
ischial spines
lesser sciatic notch
ischial tuberosity
pubis
obturator foramen
acetabulum
7-51

52. Male and Female Pelvis Female iliac bones more flared broader hips
pubic arch angle greater
more distance between ischial spine and ischial tuberosity
pelvic brim wider
sacral curvature shorter and flatter
lighter bones
7-53

53. Lower Limb Femur Patella Tibia Fibula Tarsals Metatarsals Phalanges
7-54

54. Femur (2) longest/strongest bone head fovea capitis neck
greater trochanter
lesser trochanter
linea aspera
condyles
epicondyles
7-55

55. Patella (2) kneecap anterior surface of knee
flat sesmoid bone located in a tendon
7-56

56. Tibia (2) shin bone weight bearing bone medial to fibula condyles
tibial tuberosity
anterior crest
medial malleolus
7-57

57. Fibula (2) Insert figure 7.54 lateral to tibia long, slender head
lateral malleolus
does not bear any body weight
Insert figure 7.54
7-58

58. Ankle and Foot Tarsals (14) [7 in each] Metatarsals (10) [5 in each]
calcaneus
talus
navicular
cuboid
lateral cuneiform
intermediate cuneiform
medial cuneiform
Metatarsals (10) [5 in each]
Phalanges (28) [14 in each]
proximal
middle
distal
7-59

59. Ankle and Foot
7-60

60. Life-Span Changes decrease in height at about age 30
calcium levels fall
bones become brittle
osteoclasts outnumber osteoblasts
spongy bone weakens before compact bone
bone loss rapid in menopausal women
hip fractures common
vertebral compression fractures common
7-61

61. Clinical Application Types of Fractures green stick fissured
comminuted
transverse
oblique
spiral
open
7-62