The skeletal system is composed of 206 bones that perform several important functions. The skeletal system can be divided into the axial skeleton, which includes the bones of the head, vertebral column, and thoracic cage, and the appendicular skeleton, which includes the bones of the upper and lower limbs. Key bones include the skull, vertebrae, ribs, clavicle, and bones of the upper and lower appendages. The skeletal system provides structure, movement, protection, storage, and blood cell production for the body.

1. The Skeletal System
Composed of
the 206 bones
in the human
body!!

2. Skeletal System
Functions:
1. Support – bears the weight of
the body
2. Protection- skull the brain,
ribs=lungs
3. Movement – muscles attach

3. Skeletal System
Functions:
4. Storage
*minerals such as calcium &
phosphorus are stored and
released from bone
*fat in yellow bone marrow
5. Hemopoiesis – makes blood
cells in red bone marrow

4. Skeletal System
5 Types of bones categorized by
shape:
1. Long bones
 Longer than wide
 Bear weight
 Ex. femur

5. Skeletal System
5 Types of bones categorized by shape:
2. Short bones
 About same length
as width
 Bear weight
 Ex. Carpels of wrist
and tarsals of ankle

6. Skeletal System
5 Types of bones categorized by
shape:
3. Flat bones
 Thin and usually curved
 Protect brain and thoracic
organs
 Provide wide area muscle
attachment
 Ex. Ribs, skull, shoulder

7. Skeletal System
5 Types of bones categorized by shape:
4. Sesamoid
 Small and round
 Ex. Patella of knee

8. Skeletal System
5 Types of bones categorized by shape:
5. Irregular
 Odd shaped and doesn’t fit
other categories
 Ex. vertebra

9. Skeletal System
Parts of the long bone:
Two main parts:
1. Epiphysis
*Found on the ends
*Spongy/Cancellous
bone

10. Skeletal System
Parts of the long bone:
Two main parts:
2. Diaphysis
• Shaft or long part
• Is compact bone

11. Skeletal System
Types of bone tissue:
1. Spongy bone/Cancellous bone
 contains networks of bony plates
with spaces - trabeculae
 not as dense a compact bone

12. Skeletal System
Types of bone tissue:
2. Compact bone
 dense and hard
 Shaft of bone

13. Skeletal System
Other parts of long bone:
Epiphyseal plate or growth plate:
Is hyaline tissue where growth
originates in those under 25 yrs
Epiphyseal line – in adults the
epiphyseal plate ossifies or
hardens to bone tissue

15. Skeletal System
Other parts of long bone:
Sheaths – cover the bone
a. endosteum – inner most; lines
the medullary cavity
b. periosteum – outer most; which
contains blood vessels and nerves

17. Skeletal System
Medullary cavity – central cavity of
long bone where you find yellow
or red bone marrow.
Types of Marrow:
1. Yellow bone marrow – stores fat
2. Red bone marrow – produces
red and white blood cells

19. Skeletal system is divided into
two major sections:
1. Axial skeleton –
• bones of central axis
• Includes 80 bones
• Includes: the skull, vertebral
column, and thoracic cage

20. skull
Vertebral column
Thoracic cage
Vertebral column

21. Skeletal system divided into two major sections:
2. Appendicular skeleton –
bones of upper and lower
appendages and bones that
attach them to the axial
skeleton

22. Upper appendages and girdles
Lower appendages and girdles

23. ______________________________________________________________________________________________________
The Skeletal System
Appendicular Skeleton includes:
1. Pectoral girdle
 joins the upper limbs to the axial
skeleton
 Includes the clavicle (collar bone)
and scapula(shoulder blade)

24. Appendicular skeleton includes:
Pectoral Girdle

25. ______________________________________________________________________________________________________
Appendicular Skeleton includes :
2. Pelvic girdle
 joins the lower limbs to the axial
skeleton
 Includes the 2 coxae , sacrum,
coccyx
 Coxae is formed by the fusion of
3 bones (ilium, pubis, and
ischium)

26. Appendicular skeleton includes:
Pelvic gridle
Note three bones of coxae
Coxae

27. Appendicular skeleton includes:
Pelvic gridle
Sacrum

28. Appendicular skeleton includes:
Pelvic gridle
coccyx

29. Appendicular skeleton includes:
Lower appendages include:
1. Femur
Connects to pelvic girdle
Strongest bone in body
2. Tibia – larger inner bone of lower
leg
3. Fibula – smaller outer bone of
lower leg

30. Bones of Lower Appendage

31. Appendicular skeleton includes:
Lower appendages include:
4. Patella
Knee cap
Acts as a lever to help move the
leg

32. Appendicular skeleton includes:
5. Bones of ankle and foot:
•7 tarsus (ankle)
•5 metatarsus (foot)
•5 digits (foot) each with 3 phalanges
– proximal, middle and distal
phalanges except the big toe that
has only 2 phalanges only proximal
and distal

33. Ankle and foot:
Tarsus
Tarsals
proximal
middle
distal

34. Appendicular skeleton includes:
Upper appendage includes:
1. Humerus – upper bone that
attaches limb to pectoral girdle
2. Radius – small bone of lower arm
that attaches to the thumbs
3. Ulna – small bone that attaches
to the little finger and the
humerus

35. Bones of upper appendage
Humerus

36. Appendicular skeleton includes:
:
Upper appendage includes
4. Bones of wrist and hand
• 8 carpals
• 4 distal carpals
• 4 proximal carpals
• Articulation of carpals allows
you to move the wrist

37. 5 Bones of the wrist and hand
Carpels

38. Appendicular skeleton includes:
Upper appendage includes :
4. Bones of wrist and hand
• 8 carpals
• Metacarpals – 5 long bones of
the hand numbered I-V from the
medial to lateral
(thumb to little finger)
• Digits – made of phalanges
• Three phalanges/finger
except thumb has only 2
• Proximal, middle, distal

39. 5 Bones of the wrist and hand
Metacarpals

40. 5 Bones of the wrist and hand
distal
middle
proximal
Phalanges

41. Terminology:
Proximal – means nearest the
body
Distal – means distant (away)
from the body

42. Proximal and Distal

43. The Skeletal System
Differences between skeleton of
child and adult:
More bones in youth and fuse
together as adult
Epiphyseal plate becomes line
Red bone marrow to yellow
Articular cartilage thickens

44. The Skull or Cranium
The skull protects the brain
and entrances to respiratory
and digestive systems.
The skull has 28 bones.

45. The Skull
Terminology:
Posterior – back
 Frontal – front
Lateral - side
Inferior – below
Superior - above

46. Bones of the Cranium

47. Parietal
There are two
Lateral View

48. Occipital
Only one
Lateral View

49. Temporal
There are two
Lateral View

50. Sutures – lines or joints between the
flat bones of the skulll

51. Sagittal suture – suture between the
two parietal bones, space between
when born that closes as develop.

52. PROCESSES – A
PROJECTION OF THE BONE
MASTOID PROCESS –
FOUND ON THE TEMPORAL
BONES WHERE MUSCLES
ATTACH.

53. Mastoid Process
Lateral View

54. Frontal View

55. Frontal
Frontal View

56. Nasal
Frontal View

57. Vomer
Frontal View

58. Zygomatic
bone
Frontal View

59. ZYGOMATIC ARCH –
A PROCESS FROM THE ZYGOMATIC
BONE WHICH JOINS A PROCESS OF THE
TEMPORAL BONE FORMING AN ARCH.

60. Maxilla
Frontal View

61. Mandible
Frontal View

62. MANDIBLE MOVES - only movable
bone in the skull.
MAXILLA AND MANDIBLE ARE
USED FOR CHEWING YOUR FOOD

63. Two bones of eyes
socket:
Ethmoid bone and
lacrimal bone

64. Nasal Septum:
Vomer and ethmoid bone
form nasal septum which
divides the nasal cavity in
two .

65. Frontal
Parietal
Temporal Nasal
Vomer Zygoma
Maxilla
Mandible
Frontal View

66. Mastoid Process
Lateral View

67. Frontal
Lateral View

68. Nasal
Lateral View

69. Zygomatic
Lateral View

70. Maxilla
Lateral View

71. Mandible
Lateral View

72. Sphenoid
Lateral View

73. Terminology:
Meatus – a passageway
External auditory meatus – is
the passage way that sound
waves travel to reach the
eardrum.

74. External Auditory Meatus
Passageway through which sound waves travel.
Lateral View

75. Frontal Parietal
Sphenoid
Nasal Temporal
Zygoma Occipital
Maxilla
Mastoid Process
Mandible
External Auditory Meatus
Lateral View

76. A few more things:
Foramen – a hole
Mental foramen – is in the
mandible and where the mental
nerve passes through.

77. Sinus – a hollowed out space in
the bone.

78. Nasal cavity – hollowed out,
fluid filled regions covered
with a thin mucous membrane
divided by the vomer and
ethmoid bone (septum).

79. Paranasal sinuses – air-filled
spaces connected to the nasal
cavities.

80. Sinuses reduce the weight of the
skull, warm air entering body, and
affect sound of the voice.
Orbits = eye sockets, house and
protect the eye.

81. Using page 84 in your text label
the bones of the cranium

82. Vertebral Column
Functions:
•Protects the spinal cord
•Supports the head and neck
•Bears body weight

83. Vertebral Column
It is “S” shaped and
acts as a spring or
shock absorber to
absorb the impact
when we walk.

84. Vertebral Column
It is composed of a series of
bones called vertebrae

85. Vertebral Column
It is marvelously designed to
provide strength yet flexibility.
The way the vertebrae fit
together the column
is strong yet one
can bend and rotate
the back.

86. Vertebral Column
It is marvelously designed to
provide strength yet flexibility.
The way the vertebrae fit together
or interlock gives it strength
flexibility so can bend
and rotate.

87. Vertebral Column
It is composed of 5 sections:
7 cervical vertebrae
12 thoracic vertebrae
5 lumbar vertebrae
Sacrum – 5 fused vertebrae
Coccyx – 3 fused vertebrae

88. sacrum
coccyx

90. Vertebral Column
Disorders:
At birth vertebral column in concave, and
s shape develops.
Scoliosis – abnormal sideways curve of
vertebral column.

91. Vertebral Column
Disorders:
At birth v. column in concave, and s shape developes-
Scoliosis – abnormal sideways curve of v. column
Lordosis – exaggerated curve of
lumbar – swayback

92. Vertebral Column
Disorders:
At birth v. column in concave, and s shape developes-
Scoliosis – abnormal sideways curve of v. column
Lordosis – exaggerated curve of lumbar – swayback
Kyphosis – exaggerated curve of
thoracic vertebrae = hunchback

93. Vertebral Column
Shape of the Vertebrae
Body – bears weight, bodies rest on each
other.

94. Vertebral Column
Shape of the Vertebrae
Vertebral Foramen – opening through
which the spinal cord travels.

95. Vertebral Column
Shape of the Vertebrae
Vertebral Arch – surrounds the foramen.

96. Vertebral Column
Shape of the Vertebrae
Processes – bone extensions of the
vertebrae for muscle attachment and
interlock to give mobility.
Transverse process – extends to the
sides of each vertebrae,
place for muscle/
ligament attachment.

98. Vertebral Column
Shape of the Vertebrae
Transverse process – extends to the sides of each vertebrae, place for muscle/ligament
attachment.
Spinous process – extends backward
and downward, place for muscle
attachment.

99. Vertebral Column
Shape of the Vertebrae
Transverse process – extends to the sides of each vertebrae, place for muscle/ligament
attachment.
Superior and inferior articular
processes – interlock the vertebrae

100. Intervertebral Disc - fibrous cartilage
found between the vertebrae
distributing pressure evenly across the
disc.

101. Herniated Disc - when a disc pushes
outside its normal area. Often
pinching the nerves causing pain and
numbness.

102. Thoracic Cage
Commonly called the rib cage
Protects the heart, lungs, and
other organs of the thoracic
cavity
Encloses the thoracic cavity

103. Thoracic Cage
Commonly called the rib cage
Protects the heart, lungs, and other organs of the thoracic cavity
Encloses the thoracic cavity
Composed of twelve pairs of
ribs and the sternum (breast
plate or bone)

104. Thoracic Cage
Types of Ribs
The classification of ribs:
1. True ribs – 1st 7 pairs
that attach directly to the
sternum by the coastal
cartilage

105. Thoracic Cage
Types of Ribs
The classification of ribs:
1. True ribs – 1st 7 pairs that attach directly to the sternum
by the coastal cartilage

106. Thoracic Cage
Types of Ribs
The classification of ribs:
1. True ribs – 1st 7 pairs that attach directly to the sternum by the
coastal cartilage
2. False ribs – inferior 5
pairs that connect indirectly
(first 3 pairs) to the sternum
or do not attach at all to the
sternum (last two pairs)

107. Thoracic Cage
Types of Ribs
The classification of ribs:
1. True ribs – 1st 7 pairs that attach directly to the sternum by the
coastal cartilage
2. False ribs – inferior 5 pairs that connect indirectly (first 3 pairs)
to the sternum or do not attach at all to the sternum (last two pairs)

108. Thoracic Cage
Types of Ribs
The classification of ribs:
1. True ribs – 1st 7 pairs that attach directly to the sternum by the
coastal cartilage
2. False ribs – inferior 5 pairs that connect indirectly (first 3 pairs)
to the sternum or do not attach at all to the sternum (last two pairs)
3. Floating ribs – the last
two pairs of false ribs that are
not attached at all

109. Thoracic Cage
Types of Ribs
The classification of ribs:
1. True ribs – 1st 7 pairs that attach directly to the sternum by the
coastal cartilage
2. False ribs – inferior 5 pairs that connect indirectly (first 3 pairs)
to the sternum or do not attach at all to the sternum (last two pairs)
3. Floating ribs – the last two pairs of false ribs that are not
attached at all

110. Thoracic Cage
Sternum
Connects to the ribs via
coastal cartilage
Shaped like a capital T
Found on the ventral/front
surface

111. Thoracic Cage
Sternum
Connects to the ribs via coastal cartilage
Shaped like a capital T
Found on the ventral/front surface
It consists of three parts, from above
downward:
Manubrum
Body
Xiphoid process