THE SKELETAL SYSTEM Chapter 6
Bone is made of several different tissues working together
Bone or osseous tissue
Cartilage
Dense connective tissue
epithelium
Various blood forming tissues
Adipose tissue
Nervous tissue
FUNCTIONS OF THE SKELETAL SYSTEM
Support
Supports soft tissues
Attachment sites for
tendons of most
skeletal muscles
images.webmd.com
PROTECTION
Protects internal organs from injury
www.24dr.com www.marquette.edu
ASSISTANCE IN MOVEMENT
Skeletal muscles contract and pull and bones to produce movement
www.sportsinjuryclinic.net
MINERAL HOMEOSTASIS
Stores minerals such as calcium and phosphorus.
Releases into or absorbs minerals from bloodstream
www.din.or.jp
BLOOD CELL PRODUCTION
Red bone marrow produces red blood cells, white blood cells, platelets
Hemopoiesis
hemo = blood
poiesis = to make Red blood cells,
purple: platelets,
green/gold: WBCwww.btinternet.com
TRIGLYCERIDE STORAGE
Yellow bone marrow consist of adipocytes and a few scattered blood cells.
www.udel.edu
The Skeletal System
Slide 5.1
Parts of the skeletal system
Bones (skeleton)
Joints
Cartilages
Ligaments (bone to bone)(tendon=bone to muscle)
Divided into two divisions
Axial skeleton
Appendicular skeleton – limbs and girdle
Bones of the Human Body
Slide 5.3Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
The skeleton has 206 bones
Two basic types of bone tissue
Compact bone
Homogeneous
Spongy bone
Small needle-like pieces of bone
Many open spacesFigure 5.2b
Classification of Bones
Slide 5.4aCopyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Long bones
Typically longer than wide
Have a shaft with heads at both ends
Contain mostly compact bone
• Examples: Femur, humerus
Classification of Bones
Slide 5.4bCopyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Short bones
Generally cube-shape
Contain mostly spongy bone
Examples: Carpals, tarsals
Classification of Bones on the
Basis of Shape
Slide 5.4cCopyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Figure 5.1
Classification of Bones
Slide 5.5aCopyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Flat bones
Thin and flattened
Usually curved
Thin layers of compact bone around a layer
of spongy bone
Examples: Skull, ribs, sternum
Classification of Bones
Slide 5.5bCopyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Irregular bones
Irregular shape
Do not fit into other bone classification
categories
Example: Vertebrae and hip
Classification of Bones on the
Basis of Shape
Slide 5.5cCopyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Figure 5.1
Gross Anatomy of a Long Bone
Slide 5.6Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Diaphysis
Shaft
Composed of compact bone
Epiphysis
Ends of the bone
Composed mostly of spongy bone
Figure 5.2a
Structures of a Long Bone
Slide 5.7Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Periosteum
Outside covering of the diaphysis
Fibrous connective tissue membrane
Arteries
Supply bone cells with nutrients
Figure 5.2c
Structures of a Long Bone
Slide 5.8aCopyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Articular cartilage
Covers the
external surface of
the epiphyses
Made of hyaline
cartilage
Decreases friction
at joint surfacesFigure 5.2a
Structures of a Long Bone
Slide 5.8bCopyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Medullary cavity
Cavity of the shaft
Contains yellow
marrow (mostly fat)
in adults
Contains red marrow
(for blood cell
formation) in infantsFigure 5.2a
Bone Markings (Table 6.1, Pg. 103)
Slide 5.9Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Surface features of bones
Sites of attachments for muscles, tendons,
and ligaments
Passages for nerves and blood vessels
Categories of bone markings
Projections and processes – grow out from the
bone surface
Depressions or cavities – indentations
Microscopic Anatomy of Bone
Slide 5.10a
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Osteon (Haversian System)
A unit of bone
Central (Haversian) canal
Opening in the center of an osteon
Carries blood vessels and nerves
Perforating (Volkman’s) canal
Canal perpendicular to the central canal
Carries blood vessels and nerves
Microscopic Anatomy of Bone
Slide 5.10b
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Figure 5.3
Microscopic Anatomy of Bone
Slide 5.11a
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Lacunae
Cavities containing bone cells (osteocytes)
Arranged in concentric rings
Lamellae
Rings around the central canal
Sites of lacunae Figure 5.3
Microscopic Anatomy of Bone
Slide 5.11b
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Canaliculi
Tiny canals
Radiate from the central canal to lacunae
Form a transport system
Figure 5.3
Changes in the Human Skeleton
Slide 5.12Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
In embryos, the skeleton is primarily hyaline
cartilage
During development, much of this cartilage
is replaced by bone
Cartilage remains in isolated areas
Bridge of the nose
Parts of ribs
Joints
Bone Growth
Slide 5.13a
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Epiphyseal plates allow for growth of
long bone during childhood
New cartilage is continuously formed
Older cartilage becomes ossified
Cartilage is broken down
Bone replaces cartilage
Bone Growth
Slide 5.13b
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Bones are remodeled and lengthened
until growth stops
Bones change shape somewhat
Bones grow in width
Long Bone Formation and Growth
Slide 5.14a
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Figure 5.4a
Types of Bone Cells
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Osteocytes
Mature bone cells
Osteoblasts
Bone-forming cells
Osteoclasts
Bone-destroying cells
Break down bone matrix for remodeling and release of calcium
Bone remodeling is a process by both osteoblasts and osteoclasts
Bone Fractures
Slide 5.16Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
A break in a bone
Types of bone fractures
Closed (simple) fracture – break that does not penetrate the skin
Open (compound) fracture – broken bone penetrates through the skin
Bone fractures are treated by reduction and immobilization
Realignment of the bone
Common Types of Fractures
Slide 5.17Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Table 5.2
Repair of Bone Fractures (Pg. 101)
Slide 5.18Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
1. Hematoma (blood-filled swelling) is
formed
2. Break is splinted by fibrocartilage to
form a callus
3. Fibrocartilage callus is replaced by a
bony callus
4. Bony callus is remodeled to form a
permanent patch
Stages in the Healing of a Bone
Fracture
Slide 5.19Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Figure 5.5
The Axial Skeleton
Slide 5.20a
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Forms the longitudinal part of the body
Divided into three parts
Skull
Vertebral column
Bony thorax
The Axial Skeleton
Slide 5.20b
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Figure 5.6
The Skull
Slide 5.21a
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Two sets of bones
Cranium
Facial bones
Bones are joined by sutures
Only the mandible is attached by a
freely movable joint
The Skull
Slide 5.21b
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Figure 5.7
Bones of the Skull
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Figure 5.11
Human Skull, Superior View
Slide 5.23Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Figure 5.8
Human Skull, Inferior View
Slide 5.24Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Figure 5.9
Paranasal Sinuses
Slide 5.25a
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Hollow portions of bones surrounding
the nasal cavity
Figure 5.10
Paranasal Sinuses
Slide 5.25b
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Functions of paranasal sinuses
Lighten the skull
Give resonance and amplification to voice
Figure 5.10
The Hyoid Bone
Slide 5.26Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
The only bone that
does not articulate
with another bone
Serves as a
moveable base for
the tongue
Figure 5.12
The Fetal Skull
Slide 5.27a
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The fetal skull is
large compared
to the infants
total body length
Figure 5.13
The Fetal Skull
Slide 5.27b
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Fontanelles –
fibrous membranes
connecting the
cranial bones
Allow the brain
to grow
Convert to bone
within 24 months
after birthFigure 5.13
The Vertebral Column
Slide 5.28Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Vertebrae
separated by
intervertebral discs
The spine has a
normal curvature
Each vertebrae is
given a name
according to its
locationFigure 5.14
Structure of a Typical Vertebrae
Slide 5.29Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Figure 5.16
The Bony Thorax
Slide 5.31a
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Forms a
cage to
protect
major
organs
Figure 5.19a
The Bony Thorax
Slide 5.31b
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Made-up of
three parts
Sternum
Ribs
Thoracic
vertebrae
Figure 5.19a
The Appendicular Skeleton
Slide 5.32a
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Limbs (appendages)
Pectoral girdle
Pelvic girdle
The Appendicular Skeleton
Slide 5.32b
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Figure 5.6c
The Pectoral (Shoulder) Girdle
Slide 5.33Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Composed of two bones
Clavicle – collarbone
Scapula – shoulder blade
These bones allow the upper limb to
have exceptionally free movement
Bones of the Shoulder Girdle
Slide 5.34a
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Figure 5.20a, b
Bones of the Upper Limb
Slide 5.35a
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The arm is
formed by a
single bone
Humerus
Figure 5.21a, b
Bones of the Upper Limb
Slide 5.35b
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• The forearm
has two bones
• Ulna
• Radius
Figure 5.21c
Bones of the Upper Limb
Slide 5.36Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
The hand
Carpals – wrist
Metacarpals –
palm
Phalanges –
fingers
Figure 5.22
Bones of the Pelvic Girdle
Slide 5.37Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Hip bones
Composed of three pair of fused bones
Ilium
Ischium
Pubic bone
The total weight of the upper body rests on the pelvis
Protects several organs
Reproductive organs
Urinary bladder
Part of the large intestine
The Pelvis
Slide 5.38a
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Figure 5.23a
Gender Differences of the Pelvis
Slide 5.39Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Figure 5.23c
Bones of the Lower Limbs
Slide 5.40a
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The thigh has
one bone
Femur – thigh
bone
Figure 5.35a, b
Bones of the Lower Limbs
Slide 5.40b
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The leg has
two bones
Tibia
Fibula
Figure 5.35c
Bones of the Lower Limbs
Slide 5.41Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
The foot
Tarsus – ankle
Metatarsals –
sole
Phalanges –
toes
Figure 5.25
Joints
Slide 5.43Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Articulations of bones
Functions of joints
Hold bones together
Allow for mobility
Ways joints are classified
Functionally
Structurally
Functional Classification of Joints
Slide 5.44Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Synarthroses – immovable joints
Amphiarthroses – slightly moveable
joints
Diarthroses – freely moveable joints
Structural Classification of Joints
Slide 5.45Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Fibrous joints
Generally immovable
Cartilaginous joints
Immovable or slightly moveable
Synovial joints
Freely moveable
Fibrous Joints
Slide 5.46Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Bones united by fibrous tissue –synarthrosis or largely immovable.
Figure 5.27d, e
Cartilaginous Joints – mostly
amphiarthrosis
Slide 5.47Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Bones connected by cartilage
Examples
Pubic
symphysis
Intervertebral
joints
Figure 5.27b, c
Synovial Joints
Slide 5.48Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Articulating
bones are
separated by a
joint cavity
Synovial fluid
is found in the
joint cavity
Figure 5.27f–h
Features of Synovial Joints-
Diarthroses
Slide 5.49Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Articular cartilage (hyaline cartilage)
covers the ends of bones
Joint surfaces are enclosed by a fibrous
articular capsule
Have a joint cavity filled with synovial
fluid
Ligaments reinforce the joint
Structures Associated with the
Synovial Joint
Slide 5.50Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Bursae – flattened fibrous sacs
Lined with synovial membranes
Filled with synovial fluid
Not actually part of the joint
Tendon sheath
Elongated bursa that wraps around a tendon
The Synovial Joint
Slide 5.51Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Figure 5.28
Types of Synovial Joints Based on
Shape
Slide 5.52a
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Figure 5.29a–c
Types of Synovial Joints Based on
Shape
Slide 5.52b
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Figure 5.29d–f
Inflammatory Conditions
Associated with Joints
Slide 5.53Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Bursitis – inflammation of a bursa usually caused by a blow or friction
Tendonitis – inflammation of tendon sheaths
Arthritis – inflammatory or degenerative diseases of joints
Over 100 different types
The most widespread crippling disease in the United States
Clinical Forms of Arthritis
Slide 5.54a
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Osteoarthritis
Most common chronic arthritis
Probably related to normal aging processes
Rheumatoid arthritis
An autoimmune disease – the immune system attacks the joints
Symptoms begin with bilateral inflammation of certain joints
Often leads to deformities
Clinical Forms of Arthritis
Slide 5.54b
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Gouty Arthritis
Inflammation of joints is caused by a
deposition of urate crystals from the blood
Can usually be controlled with diet
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ASSESSMENT TECHNIQUES
Bone x-rays
Bone marrow aspiration
Bone marrow biopsy
Radionuclide bone scan
Computed axial tomography (CAT)
Magnetic resonance imaging (MRI)
Bone densitometry
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DISORDERS OF THE SKELETAL SYSTEM
Ankylosing spondylitis A hereditary chronic spinal disease
Arthritis A group of disorders evidenced by inflammation of a joint, pain and stiffness during movement
Avulsion fracture Occurs when a ligament or tendon pulls off part of a bone during an injury
Bursitis Inflammation of the sac around a joint that is caused by trauma or irritation
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DISORDERS OF THE SKELETAL SYSTEM (CONTINUED)
Caries Also called cavities, it is the major cause of tooth loss
Carpal tunnel syndromeA disorder caused by pressure on the median nerve of the wrist due to repetitive use or trauma
Degenerative joint diseaseAlso called osteoarthritis, usually associated with aging; it is the most common form of arthritis
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DISORDERS OF THE SKELETAL SYSTEM (CONTINUED)
Dislocation When bones move out of their proper location, usually in the shoulder or hip
Fracture A broken bone caused by trauma
Gout A painful swelling of a joint that results from the buildup of uric acid crystals, most commonly in the great toe
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DISORDERS OF THE SKELETAL SYSTEM (CONTINUED)
Herniated diskA ruptured or “slipped” disk between vertebrae
Kyphosis Also called “hunchback” or “humpback,” is an abnormal curvature of the thoracic part of the spine
Lordosis Also called “swayback,” is an abnormal curvature of the lumbar spine
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DISORDERS OF THE SKELETAL SYSTEM (CONTINUED)
MeningomyeloceleAlso called spina bifida, is a congenital condition of the spinal column
OsteomaA bone tumor
Osteomalacia Also called rickets in children, is a softening of the bones caused by vitamin D and calcium deficiency
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DISORDERS OF THE SKELETAL SYSTEM (CONTINUED)
OsteomyelitisA bacterial infection of the bone
OsteoporosisA weakening of the bones
Paget’s diseaseAlso called osteitis deformans, is due to excessive destruction of bone cells
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DISORDERS OF THE SKELETAL SYSTEM (CONTINUED)
Periodontitis An inflammation of the tissues that keep teeth in place
Rheumatoid arthritis Pain and stiffness in the joints caused by thickening of the synovial membrane
Rickets A painless deformity at the epiphysis of the bones caused by insufficient vitamin D
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DISORDERS OF THE SKELETAL SYSTEM (CONTINUED)
ScoliosisAn abnormal lateral spinal curvature
SubluxationA partial dislocation of a joint, such as in the neck in a “whiplash” injury
TalipesA congenital deformity involving the foot and ankle
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ISSUES AND INNOVATIONSProgress in dental care
– Corrective measures including bonding, bleaching, and implants
• Bone substitutes and repairs
– Bone replacing material including organoapatites
and coral
– Surgical implants for cranial and joint injuries
– Bone regeneration