Skeletal System
Skeletal System
206 bones
Functions


1.
2.
3.
4.
5.
Supports body and provides shape
Protects internal organs
Movement and anchorage of muscles
Mineral storage (Calcium and Phosphorus)
Hemopoiesis (red marrow of the bone is the
site of blood cell formation – red marrow is in
long bones (epiphyses), sternum and ilia).
Bone formation
Osteocytes = mature bone
cell
Osteo = bone
Cyte = cell
Microscopic mature bone cells
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the skeletal system
3
Bone formation

Ossification – new minerals deposit to form
bone

Begins at 8 weeks gestation

Minerals replace previously formed cartilage.
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the skeletal system
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Bone formation



Infants bones are soft and pliable because of
incomplete ossification.
As bones ossify, they become hard.
Long bones grow in length and ossify from the
center to the ends.
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the skeletal system
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Know the following….



Osteocytes = mature bone cells
Osteoblasts = cells that actually form
bone
Osteoclasts = cells that tear down old
bone
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the skeletal system
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Bone formation
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the skeletal system
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Types of Bones
Long bones
Found in the arms and legs
Diaphysis – shaft
Epiphyses – ends
Medullary cavity – center of shaft, filled
with yellow bone marrow, which is
mostly fatty cells, also cells that form
white blood cells
Endosteum- lines marrow cavity
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Chewing with
movable skull
bone = mandible
Occipital bone connects with spinal
column
Axial Skeleton

Skull
frontal
view

What are
the
structures
of the
frontal
view of
the skull.
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the skeletal system
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Axial Skeleton

Skull
lateral
view

What are
the
structures
of the
lateral
view of
the skull.
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the skeletal system
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the skeletal system
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Axial – skull, spinal column, ribs, sternum,
hyoid
(u-shaped bone in neck to which the tongue is
attached)


Appendicular – shoulder girdle, arms, pelvis,
legs (126 bones total)
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Axial Skelton


Hyoid Bone
What is
unique about
the hyoid
bone?
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the skeletal system
15
Vertebral Column
Spine – Vertebral Column


Encloses the spinal cord
Vertebrae – separated by pads of cartilage


Cervical Vertebrae (7)
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Intervertebral discs
Atlas – 1st cervical vertebrae
Axis – 2nd cervical vertebrae
Thoracic Vertebrae (12)
Lumbar Vertebrae (5)
Sacrum
Coccyx
Appendicular Skeleton


Shoulder
girdle
Clavicle,
scapula,
humerus
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Appendicular skeleton

Clavicle = collar bone

Scapula = shoulder blade

Humerus = upper arm


Radius and ulna = lower arm (radius =
thumb side)
Carpals = wrist bones held together by
ligaments

Metacarpals = hand bones

Phalanges = fingers

Pelvis = 3 bones (ilium, ischium, and pubis)

Femur = upper leg, longest and strongest bone in
the body
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
Tibia and Fibula = lower leg (tibias touch –
tibia is larger of the two bones)

Sternum = breast bone

Patella = kneecap

Tarsal bones = ankle bones

Calcaneus = heel bone

Metatarsals = foot bones
Appendicular Skeleton


Pelvis
Pelvic girdle
= ilium,
ischium and
pubis
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Joints

Joints are points of contact between 2
bones- classified according to movement:





Diarthrosis – movable
Amphiarthrosis – partially movable
Synarthrosis – immovable
Articular cartilage – covers joint surface
Synovial Fluid – lubricating substance in
joints
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the skeletal system
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Joints

Ball and socket




One bone has a ball at one
end
The other has a concave
socket
Allows for the greatest
range of motion
Ex: shoulder
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the skeletal system
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Joints

Hinge joint

Move in one direction
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Joints:
Diarthroses


Example of
a hinge
joint.
Define
uniaxial…
permits
movement
in one axis
only
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Joints

Pivot joints

Bones that rotate across
each other
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the skeletal system
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Joints

Gliding joint


Bones with flat surfaces
that slide across each
other
i.e. bones in ankle and
hand
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Joints

Amphiarthroses

Partially movable joints
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Joints

Synarthroses


Immovable joints
Connected by fibrous
connective tissue
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the skeletal system
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Bursa and
Synovial Membrane

Bursa


Fluid-filled sac that
contains the synovial
membrane
Lined by synovial
membrane
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the skeletal system
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Bursa and
Synovial Membrane

Synovial membrane
 Capsule that
encloses a joint


Lines the bursa
Contains synovial fluid
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the skeletal system
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Types of movement

Flexion is a
position that is
made possible
by the joint
angle
decreasing.
Extension
A movement of
a joint in
which one
part of the
body is
moved away
from another.
i.e. going from sitting
to standing

Abduction

Adduction
A motion that pulls
a structure or part
away the midline of
the body.
A motion that pulls
a structure or part
towards the midline
of the body
Circumduction

The circular or a
more precise
movement of a
body part, such
as a ball-andsocket joint or
the eye.
Rotation

A motion that
occurs when a
part turns on
its axis.
i.e. shaking your
head “no”
Pronation

A rotation of the
forearm that
moves the palm
from an anteriorfacing position to
a posterior-facing
position, or palm
facing down.
Supination

The opposite of
pronation, the
rotation of the
forearm so that
the palm faces
anteriorly, or
palm facing up.
Disorders of the
Skeletal System

Arthritis

Arthritis = An inflammation of one or
more joints.

Osteoarthritis- degenerative, occurs with
aging, 80% of Americans suffer, joints
become enlarged and painful
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Disorders of the
Skeletal System

Arthritis

Rheumatoid arthritis = A chronic,
autoimmune disease = joints become swollen
and painful, joint deformities common
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and disorders of the skeletal
system
42
Rheumatoid
arthritis
Osteoarthritis
Disorders of the
Skeletal System


Gout
Increase of uric acid
deposited in joint cavity,
mostly the great toe in men.
1.03 Understand the functions
and disorders of the skeletal
system
44
Disorders of the
Skeletal System


Osteoporosis- most of
those affected are women.
Mineral density of bone is
reduced 35% – 65%. The
loss of bone mass leaves
the bone thinner, more
porous and more prone to
fracture. (soft like a sponge)
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Disorders of the
Skeletal System

Osteoporosis


How do you
think
osteoporosis
treated?.
Why is her
height
decreasing?
1.03 Understand the functions
and disorders of the skeletal
system
47
Disorders of the
Skeletal System

Rickets


Found in children,
caused by lack of
vitamin D, bones
become soft.
Is this a common
problem in the US? Why
or why not?
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Disorders of the
Skeletal System

Abnormal spinal curvatures
Kyphosis
Lordosis
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and disorders of the skeletal
system
Scoliosis
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Skeletal System Trauma

Dislocation


Separation of
bones in a joint
Subluxation =
partial
separation
(dislocation)
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and disorders of the skeletal
system
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Skeletal System Trauma

Fracture- a break in a bone

Treated by:
 Closed reduction- cast or splint applied
 Open reduction- surgical intervention with
devices such as wired, metal plates or
screws to hold bone in alignment
 Traction- pulling force used to hold the
bone in place
 Used for fractures of long bones
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
Closed or simple

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Open or compound


in children, bone bent and splintered but
never completely separates
Comminuted


broken bone pierce the skin, can lead to
infection
Greenstick


bone broken, broken ends don’t break skin
splintered or broken into many pieces
Spiral

bone twists, resulting in one or more breaks
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