PowerPoint Presentation to Accompany
© 2010 Delmar, Cengage Learning
1
Chapter 7
The Skeletal System
© 2010 Delmar, Cengage Learning
2
Introduction
• Skeleton: supporting structure
• Bones and associated cartilage, tendons
and ligaments
• Works with muscles for movement
• Mineral salts form the inorganic matrix of
bone
• Leonardo da Vinci: constructed first
correct illustrations of all bones
© 2010 Delmar, Cengage Learning
3
The Functions of the Skeletal
System
© 2010 Delmar, Cengage Learning
4
The Functions of the Skeletal
System (cont’d.)
•
•
•
•
•
Supports surrounding tissues
Protects vital organs and soft tissues
Provides levers for muscles to pull on
Manufactures blood cells
Stores mineral salts
© 2010 Delmar, Cengage Learning
5
The Functions of the Skeletal
System (cont’d.)
• Cartilage
– Connective tissue
– Environment in which bone develops in fetus
– Found at ends of bones and in joints
• Ligaments
– Attach bones to bones
• Tendons
– Attach muscles to bones
© 2010 Delmar, Cengage Learning
6
The Growth and Formation of
Bone
© 2010 Delmar, Cengage Learning
7
Introduction
• A three-month fetal skeleton is
completely formed (cartilage)
• Ossification and growth begin
• Longitudinal growth continues until:
– 15 years of age for girls
– 16 years of age for boys
• Bone maturation until 21 years of age
© 2010 Delmar, Cengage Learning
8
Deposition of Bone
• Osteoblasts: embryonic bone cells
• Osteocytes: mature osteoblasts
• Strain on bone (exercise) increases bone
strength
• Osteoclasts: bone reabsorption and
remodeling
© 2010 Delmar, Cengage Learning
9
Types of Ossification
• Intramembranous
– Dense connective membranes replaced by
calcium salts
– Cranial bones
• Endochondral
– Bone develops inside cartilage environment
– All other bones of the body
© 2010 Delmar, Cengage Learning
10
Maintaining Bone
• Endocrine system control
– Calcium storage
– Blood calcium levels
– Excretion of excess calcium
• Parathormone: calcium release
• Calcitonin: calcium storage
© 2010 Delmar, Cengage Learning
11
The Histology of Bone
© 2010 Delmar, Cengage Learning
12
Introduction
• Two types of bone: compact and
cancellous (spongy)
– Osteocytes same but arrangement of blood
supply different
– Cancellous has bone marrow
© 2010 Delmar, Cengage Learning
13
The Haversian System of Compact
Bone
• Clopton Havers: histology of compact
bone
• Haversian canals: run parallel to surface
– Surrounded by concentric rings of bone
– Lacunae: cavity containing osteocyte
– Lacunae connected by canaliculi
© 2010 Delmar, Cengage Learning
14
Cancellous Bone
• Trabeculae: meshwork of bone
• Spongy appearance created by trabeculae
• Bone marrow fills spaces between
trabeculae
© 2010 Delmar, Cengage Learning
15
Bone Marrow
• Red marrow
– Hematopoiesis
– Ribs, sternum, vertebrae, pelvis
• Yellow marrow
– Fat storage
– Shafts of long bones
© 2010 Delmar, Cengage Learning
16
The Classification of Bones
Based on Shape
© 2010 Delmar, Cengage Learning
17
Introduction
© 2010 Delmar, Cengage Learning
18
Long Bones
• Length exceeds width
• Consist of
– Diaphysis: shaft
– Metaphysis: flared portion
– Epiphysis: extremity
© 2010 Delmar, Cengage Learning
19
Long Bones
(cont’d.)
• Structure
of a long
bone
© 2010 Delmar, Cengage Learning
20
Short Bones
• Not merely shorter versions of long bones
• Lack a long axis
• Somewhat irregular shape
© 2010 Delmar, Cengage Learning
21
Flat Bones
• Thin bones found wherever need for
extensive muscle attachment
• Usually curved
© 2010 Delmar, Cengage Learning
22
Irregular Bones
• Very irregular shape
– Example: vertebrae
• Spongy bone enclosed by thin layers of
compact bone
© 2010 Delmar, Cengage Learning
23
Sesamoid Bones
• Small rounded bones
• Enclosed in tendon and fascial tissue
• Located adjacent to joints
© 2010 Delmar, Cengage Learning
24
Bone Markings
© 2010 Delmar, Cengage Learning
25
Introduction
• Processes: projections
• Fossae: depressions
• Functions: muscle attachment, articulation,
passageways
© 2010 Delmar, Cengage Learning
26
Processes
• Processes: projections from the surface
– Spine, condyle, tubercle, trochlea, trochanter,
crest, line, head, neck
© 2010 Delmar, Cengage Learning
27
Fossae
• Fossae: depressions
– Suture, foramen, meatus, sinus, sulcus
© 2010 Delmar, Cengage Learning
28
Divisions of the Skeleton
© 2010 Delmar, Cengage Learning
29
Divisions of the Skeleton (cont’d.)
• Typically has 206 named bones
• Axial part
– Skull, hyoid, vertebrae, ribs, sternum
• Appendicular part
– Upper extremities or arms
– Lower extremities or legs
© 2010 Delmar, Cengage Learning
30
Divisions of the
Skeleton (cont’d.)
• Adult human skeleton:
anterior view
© 2010 Delmar, Cengage Learning
31
Divisions of the
Skeleton (cont’d.)
• Adult human
skeleton: posterior
view
© 2010 Delmar, Cengage Learning
32
The Axial Skeleton
© 2010 Delmar, Cengage Learning
33
The Cranial Bones
•
•
•
•
•
•
•
Frontal bone (1)
Parietal bones (2)
Occipital bone (1)
Temporal bone (2)
Sphenoid bone (1)
Ethmoid bone (1)
Auditory ossicles (6)
© 2010 Delmar, Cengage Learning
34
The Facial Bones
•
•
•
•
•
•
Nasal bones (2)
Palatine bones (2)
Maxillary bones (2)
Zygomatic bones (2)
Lacrimal bones (2)
Nasal conchae (2)
© 2010 Delmar, Cengage Learning
35
The Facial Bones (cont’d.)
• Vomer bone (1)
• Mandible (1)
© 2010 Delmar, Cengage Learning
36
The Facial
Bones (cont’d.)
• Bones of
the face
and skull,
lateral view
© 2010 Delmar, Cengage Learning
37
The Orbits
• Orbits: cavities enclose and protect the
eyes
Area of Orbit
Participating Bones
Roof
Frontal, sphenoid
Floor
Maxilla, zygomatic
Lateral wall
Zygomatic, greater wing of
sphenoid
Medial wall
Maxilla, lacrimal, ethmoid
© 2010 Delmar, Cengage Learning
38
The Nasal Cavities
• Nose framework surrounds the two nasal
cavities
Area of Nose
Participating Bones
Roof
Ethmoid
Floor
Maxilla, palatine
Lateral wall
Maxilla, palatine
Septum of medial wall
Ethmoid, vomer, nasal
Bridge
Nasal
© 2010 Delmar, Cengage Learning
39
The Foramina of the Skull
• Passageways for blood vessels and
nerves
• Foramen magnum: spinal cord passage
© 2010 Delmar, Cengage Learning
40
The Hyoid Bone
• No articulation with other bones
• Suspended by ligaments from styloid
process
• Supports the tongue
© 2010 Delmar, Cengage Learning
41
How to Study the Bones of the
Skull
• Refer to colored plates in textbook
• Use a model of a human skull
• Search for sutures as a guide
© 2010 Delmar, Cengage Learning
42
The Torso or Trunk
• Vertebrae
– Seven cervical
– Twelve thoracic
– Five lumbar
– Sacrum
– Coccyx
© 2010 Delmar, Cengage Learning
43
The Thorax
• Thorax or rib cage made up of:
– Sternum
– Costal cartilages
– Ribs
– Bodies of thoracic vertebrae
• Encloses and protects heart and lungs
© 2010 Delmar, Cengage Learning
44
The Thorax (cont’d.)
© 2010 Delmar, Cengage Learning
45
The Sternum
• Breastbone
• Has three parts
– Manubrium
– Gladiolus
– Xiphoid process
• Attachment for diaphragm and rectus abdominis
© 2010 Delmar, Cengage Learning
46
The Ribs
• Also called costae
• Attach posteriorly to thoracic vertebrae
• 12 pairs
– True ribs, false ribs, floating ribs
© 2010 Delmar, Cengage Learning
47
The Appendicular Skeleton
© 2010 Delmar, Cengage Learning
48
The Bones of the Upper
Extremities
• Shoulder girdle: clavicle and scapula
• Arm
– Upper arm: humerus
– Forearm: ulna and radius
– Wrist: carpals
– Hand: metacarpals (5/hand)
– Fingers: phalanges (14/hand)
© 2010 Delmar, Cengage Learning
49
The Bones of the
Upper Extremities
(cont’d.)
• Bones of
the wrist
and hand
© 2010 Delmar, Cengage Learning
50
The Bones of the Lower
Extremities
• Pelvic girdle: ischium, ilium, pubis
• Leg
– Upper leg: femur
– Lower leg: patella, tibia, fibula
– Foot
• Tarsals
• Metatarsals (5/foot)
• Phalanges (14/foot)
© 2010 Delmar, Cengage Learning
51
The Bones of the Lower
Extremities (cont’d.)
• Right ankle
and foot,
lateral view
© 2010 Delmar, Cengage Learning
52
The Bones of the
Lower Extremities
(cont’d.)
• Right ankle and
foot, superior view
© 2010 Delmar, Cengage Learning
53
The Arches of the Foot
© 2010 Delmar, Cengage Learning
54
The Arches of the Foot (cont’d.)
• Enable foot to bear weight while standing
and to provide leverage while walking
• Medial longitudinal: highest
• Lateral longitudinal
• Transverse
• Pes planus: flat foot
© 2010 Delmar, Cengage Learning
55
Animation – Twisting Force
• The following animation illustrates the
damage that can occur to muscle, bone, or
joint due to a twisting action
[Insert twisting force.swf]
© 2010 Delmar, Cengage Learning
56
Animation – Direct Force
• The following animation illustrates a
fracture due to direct force to the bone
from another object.
[Insert direct force.swf]
© 2010 Delmar, Cengage Learning
57
Summary
• Listed the functions of the skeletal system
• Described the process of growth and
formation of bone
• Described the structure of compact and
cancellous bone
• Defined the various processes and fossae
associated with bones
© 2010 Delmar, Cengage Learning
58
Summary (cont’d.)
• Named the bones of the axial and
appendicular skeleton
• Described the arches of the foot
© 2010 Delmar, Cengage Learning
59