Transcript Bones and the Skeleton


Support
› Allows us to stand erect.

Protection
› Ribs protect the heart and lungs.

Movement
› Serve as attachment for skeletal muscles

Storage
› Mineral, including calcium

Blood Cell Formation
› hematopoiesis

Compact (dense) bone
› Looks smooth and homogeneous

Spongy (cancellous) bone
› Composed of small needlelike or flat pieces
called trabeculae.
› Has a lot of open space.

Compact
bone:
› Filled with
canals and
passages
for nerves
and
vessels.
› Structural
unit is the
osteon or
Haversian
system.

Spongy Bone
› Consists of
trabeculae.
› No osteons are
present.
Diaphysis- shaft of the long bone.
Consists of a collar of compact bone
surrounding a medullary cavity.
 Epiphyses- ends
 Epiphyseal Line- remainder of the growth
plate. (cartilage)
 Endosteum- thin membrane lining the
medullary cavity. Contains osteoblasts
and osteoclasts.

Red marrow is found in long bones and flat bones. This is the
area where blood cell production takes place.


Some illnesses can
only be cured with a
bone marrow
transplant.
What do you think
you know about this
process?

Remodeling
› Coordinated by packets of osteoblasts and
osteoclasts called remodeling units.
› In healthy adults, bone mass remains
constant.
› Controled by 2 loops
 1. mechanical and gravitational forces
 2. negative feedback hormonal mechanism.

blood calcium
release of PTH
Ca from bone by osteoclasts.
release of
Phases of fracture healing.
Types of fractures.

Osteogenesis and ossification
› Fetal skeleton is mostly hyaline cartilage.
› Gradually replaced by bone and hardened.
› Flat and irregular bones are formed by
intramembranous ossification.
› Long and short bones are formed by
endochondral ossification.

Longitudinal
› Growth at the epiphyseal plate by mitosis.
› Grow in length.

Appositional
› Increases bone thickness.
*Growth hormone released during infancy and
childhood

Osteoporosis
› Reduced by mass due to increased bone
reabsorption.

Osteomalacia/ Rickets
› Bones do not have enough calcium, making
them soft.
› Caused by Vit. D deficiency.

Paget’s Disease
› Excessive and abnormal bone formation.
•Flat
•long
•Short
•irregular

Two types of bone markings:
› Projections (aka processes) that grow out
from the bone
› Depressions (cavities) that indent the bone

Condyle: Rounded
articular projection

Head: bony
expansion on a
narrow neck

Facet: smooth, nearly
flat articular surface
head
Facet

Ramus: Armlike bar
of bone
Crest: Narrow ridge of
bone (Line: smaller
than a crest)
Epicondyle: Raised
area on or above a
condyle
Tubercle: Small
rounded projection
Tuberosity: large
rounded or
roughened
projection
Trochanter: very
large, blunt
projection
(only on femur)
Spine: Sharp, pointed
projection
Ex: sharp points on
the throacic
vertebrae.

Allow blood vessels
or nerves to pass
through.
› Meatus: (me - A-
tus) Canal or tube
› Sulcus, Groove or
Furrow: a shallow
depression
Sinus: Cavity within a
bone; filled with air
and lined with
mucous
membranes
Foramen: Round or
oval opening
Foramen Magnum
Fossa: shallow basin
Fissure: narrow, slit-like
opening
Projections
1) Condyle
2) Head
3) Facet
4) Ramus
5) Crest
6) Epicondyle
7) Tubercle
8) Tuberosity
9) Trochanter
10) Spine
Depressions
1) Meatus
2) Fossa
3) Fissure
4) Sinus
5) Sulcus or Groove or
Furrow
 Axial:
skull,
vertebral column
and bony thorax.
 Appendicular:
hang from 2
yokelike, bony
girdles anchored
to axial skeleton.
The Skull
 Two sets of bones
 Cranium
 Facial bones
 Bones are joined by sutures
 Only the mandible is attached by a freely
movable joint
The Skull
Bones of the Skull
Figure 5.11
Human Skull, Superior View
Figure 5.8
Human Skull, Inferior View
Figure 5.9
The Fetal Skull
 The fetal skull is
large compared
to the infants
total body length
Figure 5.13
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The Fetal Skull
 Fontanelles –
fibrous membranes
connecting the
cranial bones
 Allow the brain
to grow
 Convert to bone
within 24 months
after birth
Figure 5.13
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The Hyoid Bone
 The only bone that
does not articulate
with another bone
 Serves as a
moveable base for
the tongue
Figure 5.12
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The Vertebral Column
 Vertebrae
separated by
intervertebral discs
 The spine has a
normal curvature
 Each vertebrae is
given a name
according to its
location
Figure 5.14
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Structure of a Typical Vertebrae
Figure 5.16
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The spinal column contains
33 bones termed vertebrae. The
spine has five regions.


Region
Cervical
Thoracic
Lumbar
Sacrum
Coccyx
# of Vertebrae
7
12
5 or 6
5 (fused)
3
Body Area
Neck
Chest
Low Back
Pelvis
Tailbone
Abbreviation
C1 - C7
T1 - T12
L1 - L5
S1 - S5
None

Atlas (C1)
› first cervical vertebra, C1.
› supports the skull.
› It looks different than other
vertebrae. The Atlas is a ringshaped bone.

Axis (C2)
› second cervical vertebra, C2.
› It looks like a dull tooth and
sticks upward into the ring of
the Atlas. The dens or tooth
extends up from the C2 and
joins with the inside of the C1
ring.
**The Atlas and Axis allow the
head to turn from side to side.
The Bony Thorax
 Forms a
cage to
protect
major
organs
Figure 5.19a
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The Bony Thorax
 Made-up of
three parts
 Sternum
 Ribs
 Thoracic
vertebrae
Figure 5.19a
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The Appendicular Skeleton
Figure 5.6c
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The Pectoral (Shoulder) Girdle
 Composed of two bones
 Clavicle – collarbone
 Scapula – shoulder blade
 These bones allow the upper limb to
have exceptionally free movement
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Bones of the Shoulder Girdle
Figure 5.20a, b
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Bones of the Shoulder Girdle
Figure 5.20c, d
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Bones of the Upper Limb
 The arm is
formed by a
single bone
 Humerus
Figure 5.21a, b
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Bones of the Upper Limb
• The forearm
has two bones
• Ulna
• Radius
Figure 5.21c
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Bones of the Upper Limb
 The hand
 Carpals – wrist
 Metacarpals –
palm
 Phalanges –
fingers
Figure 5.22
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Bones of the Pelvic Girdle
 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
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The Pelvis
Figure 5.23a
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The Pelvis
Figure 5.23b
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Gender Differences of the Pelvis
Figure 5.23c
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Bones of the Lower Limbs
 The thigh has
one bone
 Femur – thigh
bone
Figure 5.35a, b
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Bones of the Lower Limbs
 The leg has
two bones
 Tibia
 Fibula
Figure 5.35c
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Bones of the Lower Limbs
 The foot
 Tarsus – ankle
 Metatarsals –
sole
 Phalanges –
toes
Figure 5.25
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Arches of the Foot
 Bones of the foot
are arranged to
form three strong
arches
 Two longitudinal
 One transverse
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Figure 5.26
Joints
 Functions
 Hold bones together
 Allow for mobility
 Ways joints are classified
 Functionally
 Structurally
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Functional Classification of
Joints
 Synarthroses – immovable joints
 Amphiarthroses – slightly moveable
joints
 Diarthroses – freely moveable joints
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Structural Classification of
Joints
 Fibrous joints
 Generally immovable
 Cartilaginous joints
 Immovable or slightly moveable
 Synovial joints
 Freely moveable
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Fibrous Joints
 Bones united by fibrous tissue
 Examples
 Sutures
 Syndesmoses
 Allows more
movement than
sutures
 Example: distal
end of tibia and
fibula
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Figure 5.27d, e
Cartilaginous Joints
 Bones connected by cartilage
 Examples
 Pubic
symphysis
 Intervertebral
joints
Figure 5.27b, c
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Synovial Joints
 Articulating
bones are
separated by a
joint cavity
 Synovial fluid
is found in the
joint cavity
Figure 5.27f–h
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Features of Synovial Joints
 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
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Inflammatory Conditions Associated
with Joints
 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
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Clinical Forms of Arthritis
 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
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Clinical Forms of Arthritis
 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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