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Skeletal System
Skeletal System Functions

Provides shape and support.
Video Notes Anatomy Skeletal System Support
Skeletal System Functions
Enables you to
move.
 Skeletal muscles,
which are attached
to bones by
tendons, pull on
the bones to
produce
movement.

Skeletal System Jobs
Protects your internal organs.
 Your heart and lungs are shielded by
your ribs.
 Your brain is protected by your skull.
 Your spinal cord is protected by your
vertebral column.

Video Notes Anatomy Skeletal System Bones Protect
Skeletal System Jobs
Produces blood cells.
 Some of your bones are filled with
special material that makes red and
white blood cells.

Video Notes Anatomy Skeletal System Bones Make Blood
Skeletal System Jobs

Stores minerals, fats, and other
substances.
Types of Bone
 Compact
bone: has no visible
open spaces and provides most
of the strength and support for a
bone.
Types of Bone

Spongy bone: has many open spaces
which makes the bone light, but
strong.
Bone Marrow

Bone marrow is a soft tissue found
inside the bones that makes red
blood cells and stores fat.
Video Notes Anatomy Skeletal System Bone Types
Cartilage

Cartilage- soft, flexible tissue that is
part of the skeletal system. Makes up
the nose and ears, and helps cushion
the area where two bones meet.
Video Notes Anatomy Skeletal System Cartilage
Joints

Joints- the place where two or more
bones connect and allow for
movement.
Video Notes Anatomy Skeletal System Types of Joints
Joints or “Articulations”


Articulation = place where two bones
come together
Classification methods:

Function:

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Synarthrosis (non-movable)
Amphiarthrosis (slightly movable)
Diarthrosis (freely movable)
Structure (connective tissue type):

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Fibrous (fibrous tissue)
Cartilaginous (cartilage)
Synovial (synovial fluid)
Fibrous joints
1.
•
•
No movement
Sutures in fetal skull
Cartilaginous joints
2.
•
•
Slight movements
Epiphyseal plates, costal cartilage
Synovial joints
3.
•
•
Free movements
Most joints (wrist, knee, shoulder, hip, etc.)
Fibrous Joints
Synovial Joints
Ball and Socket Joint
 Ball
and Socket Joint: allow the
greatest range of motion, like your
shoulder and hip.
Hinge Joint

Hinge Joint: like the hinge of a door,
allows forward or backward motion.
Knee Joint
Elbow Joint
Pivot Joint

Pivot Joint: allows one bone to rotate
around another, neck and head.
Sliding Joint

Sliding Joint: allows one bone to slide
over another, wrist and ankles.
Types of Joint Movements
1. Flexion vs. extension
2. Plantar flexion vs. dorsiflexion
3. Abduction vs. adduction
4. Pronation vs. supination
5. Eversion vs. inversion
6. Rotation
7. Protraction vs. retraction
8. Elevation vs. depression
9. Circumduction
10.Excursion (mandible moving side to side)
11.Opposition vs. reposition (thumb & pinky together,
then apart)
Bone to Bone

Ligaments- connects bone to bone.
Bone to Muscle

Tendons- connects muscle to bone.
Divisions of the Skeleton

Axial skeleton


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
Skull
Hyoid bone
Vertebral column
Thoracic (rib) cage
Appendicular skeleton


Limbs
Girdles
7-27
Axial skeleton
1. Skull (28 bones including auditory ossicles)
2. Hyoid bone (1 bone)
3. Vertebral column (26 bones)
a. Cervical (7 vertebrae)
b. Thoracic (12 vertebrae)
c. Lumbar (5 vertebrae)
d. Sacrum (1 – 5 fused vertebrae)
e. Coccyx (1 -~4 fused vertebrae)
4. Thoracic Cage (25 bones)
a. Ribs (24)
b. Sternum (1 – 3 parts)
80 total bones in axial skeleton
The Skull – 28 bones

Braincase – encloses
cranial cavity

Surrounds & protects brain


Facial bones – forms facial
structure


6 bones, 8 when paired
8 bones, 14 when paired
Auditory ossicles – form
the middle ear

These bones transmit vibration
to eardrum

Malleus, incus, & stapes
Hyoid bone




U-shaped
Not part of skull
No direct bony attachment
to skull (attached by
muscles & ligaments)
Attachment site for tongue
& larynx muscles (speech
& swallowing)
Vertebral Column



“Backbone”
Central axis of skeleton
5 regions:

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Cervical vertebrae (neck + to turn) (C1-C7)
Thoracic vertebrae (T1-T12)
Lumbar vertebrae (L1-L5)
Sacral (S)
Coccygeal bone (CO)
4 curves:




Cervical curves anteriorly
Thoracic curves posteriorly
Lumbar curves anteriorly
Sacral & coccygeal curve posteriorly
Functions of Vertebral Column

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Supports weight of head & trunk
Protects spinal cord
Allows spinal nerves to exit spinal cord
Site for muscle attachment
Permits head & trunk movement
Vertebral Column

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
“Backbone”
Central axis of skeleton
5 regions:

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
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
Cervical vertebrae (neck + to turn) (C1-C7)
Thoracic vertebrae (T1-T12)
Lumbar vertebrae (L1-L5)
Sacral (S)
Coccygeal bone (CO)
4 curves:

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
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Cervical curves anteriorly
Thoracic curves posteriorly
Lumbar curves anteriorly
Sacral & coccygeal curve posteriorly
Vertebral Column Defects

Lordosis –
abnormal anterior
curvature



Kyphosis –
abnormal posterior
curvature



Lumbar
Swayback
Usually upper thoracic
Hunchback
Scoliosis –
abnormal lateral
curvature
Vertebral Column Damage

Herniated disk


Compresses nerves
“Broken Tailbone”

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Fractured coccyx
Can occur during
childbirth and from
falls
Thoracic Cage


“Rib cage”
Functions:



Protects vital organs in thorax
Prevents collapse of thorax during respiration
Consists of:

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Thoracic vertebrae
Ribs + associated cartilages
Sternum
Ribs & Costal Cartilages

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12 pairs (24 total)
Articulate with thoracic vertebrae
True ribs – (1-7) superior 7 attach to sternum via cartilage
False ribs – (8-12) inferior 5 do not directly attach to sternum
 Floating ribs – (11-12) inferior 2 not attached to sternum at all
Sternum


“Breastbone”
Three parts:

Manubrium (handle)

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Body


Jugular notch – superior to
manubrium; between clavicular
articulations
Sternal angle – at junction of
manubrium & body; locates 2nd
rib & used to find apex of heart
Xiphoid process (sword)

Used in CPR alignment
Appendicular Skeleton

Girdles
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Upper Limbs
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Pectoral or shoulder
Pelvic
Arm
Forearm
Wrist
Hand
Lower Limbs
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Thigh
Leg
Foot
7-41
Pectoral Girdle
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2 scapulae
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Articulates with
humerus
2 clavicles

Articulates with
sternum & scapula
Pelvic Girdle

2 coxae

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Coxa formed by 3 fused bones: ilium, ischium,
pubis
Sex differences: larger pelvic inlet and outlet in
females, broader pelvis in females, greater
subpubic angle in females (childbirth)
Comparison of the Male
and Female Pelvis
7-44
Upper Limb

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Arm
Forearm
Wrist
Hand
Upper Limb: Arm

Humerus –
region between
shoulder and
elbow
Upper Limb: Forearm

Radius (lateral or thumb
side) & Ulna (medial or
little finger side)
Upper Limb: Wrist & Hand

Wrist – region between
forearm and hand


8 carpals
Hand – attached to
carpals

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5 metacarpals
5 digits
3 phalanges per finger (2
on thumb)
Lower Limb
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Thigh
Leg
Ankle
Foot
Lower Limb: Thigh

Femur – region
between hip and
knee

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Articulates with
coxa and tibia
Patella
Lower Limb: Leg

Tibia (shin) and
fibula
Lower Limb: Foot & Ankle

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Ankle = 7 tarsals; articulates with tibia &
fibula; calcaneus forms heel
Foot = 5 metatarsals; 3 phalanges per digit
(except great toe – has 2)