ANATOMY AND
PHYSIOLOGY
Chapter 6
The Skeletal
System
206
_________
bones
bone
Osseous - __________
One of the
hardest
__________ material in
the body
The Skeleton is
2
divided into _______
divisions.
Axial
Skull, vertebral column,
bony thorax
Appendicular
Limbs and girdles
We will also talk about:
Joints
Point where two
bones meet
We will also talk about:
Cartilage
Connective
tissue that
protects or
connects.
We will also talk about:
Tendons
Connects
muscles to
muscles or
muscles to
bones
Functions of the Skeletal System
Support
Legs support the
body when we
stand.
Ribs support thorax
Functions of the Skeletal System
Protection
Skull protects
brain.
Ribs protect
heart, lungs.
Functions of the Skeletal System
Movement
Muscles attach
to bones by
tendons. Bones
are used as
levers
Functions of the Skeletal System
Storage
Bones store fat
and mineral
such as
calcium and
phosphorus
Functions of the Skeletal System
Blood cell
formation
Hematopoiesis.
In the narrow
cavities of the
bones
Classification of Bones according to
Tissue type
Compact
dense
Spongy
Lots of
open
spaces
Classification of Bones according
to size and shape
Long bones
Mostly compact
Usually longer than wide
Usually have a shaft with
heads at both ends
All the bones of the
limbs except wrist and
ankles.
Classification of Bones according
to size and shape
Short bones
Generally cubed
shape
Mostly spongy
bone
Wrists and
ankles
Classification of Bones according
to size and shape
Flat bones
Thin, flat and
usually curved
Spongy bone
sandwiched btw
2 thin layers of
compact bone
Skull, ribs,
sternum
Classification of Bones according
to size and shape
Irregular bones
Mostly compact
Bones that do
not fit other
categories
Vertebrae,
Hip bones
Structure of a Long Bone
Shaft
Made of
compact
bone
Covered by
membrane
called
periosteum
diaphysis
Structure of a Long Bone
Diaphysis
The internal cavity
called the
medullary canal is
a storage area for:
adipose or fat
yellow marrow
Structure of a Long Bone
Ends
epiphysis
Made of thin layer of
compact bone
enclosing spongy bone
Covered with articular
cartilage ( a smooth
slippery surface
Contains red marrow
Structure of a Long Bone
Epiphyseal
line
Left over from
epiphyseal plate
Structure of a Long Bone
Epiphyseal
Plate
Flat plate of hyaline
cartilage seen in young
growing bones
This plate is replaced
by bone when growth is
complete
1. epiphysis.
2. diaphysis
3. epiphysis
4.
Articular cartilage
5. Spongy bone
6. Compact bone
7. Medullary canal
8. Yellow marrow
9.
Compact bone
10. periosteum
Bone Markings
Crest
2. Narrow
ridge,
usually
prominent
Bone Markings
Epicondyle
1. Raised
area on a
condlye
Bone Markings
Trochanter
3. Very
large,
irregularly
shaped,
located on
femur
Bone Markings
Head
2. Bony
expansion
carried on a
narrow neck
Bone Markings
Condyle
1. Rounded
articular
projection
Bone Markings
Fissure
3. Narrow slit
like opening
Bone Markings
Sinus
2. Cavity
within a
bone
Bone Markings
Foramen
1. Round or
oval opening
through a bone
Bone Markings
Foramen
1. Round or
oval opening
through a bone
2.
Label
1.
Greater
trochanter
Head
3.
Greater
trochanter
7.
8.
Neck
crest
4. Lesser
Trochanter
9.
crest
Condyle
Condyle
6.
5.
condyle
11.
10.
epicondyle
Microscopic Anatomy
Osteocytes –
mature bone
cells
Microscopic Anatomy
Lacunae –
tiny cavities
within the matrix
of compact bone
Microscopic Anatomy
Haversian
Canals:
Run length wise
thru bone.
Carry blood
vessels and
nerves to
bones
Microscopic Anatomy
Calcium
gives the
bone its
strength
Microscopic Anatomy
Organic
parts provide
for the bone
flexibility
example:
collagen
fibers
Protein
found in
connective
tissue
Bone Formation and Growth
Skeleton starts
out as cartilage
but is replaced
by bone in most
places.
Exceptions?
Bridge of nose,
parts of ribs,
joints
Bone Formation and Growth
Process of
bone
formation is
ossification
Bone forming
cells are
called
osteoblasts
Bone Formation and Growth
Bones change in
response to:
Calcium levels in
blood
Pull of gravity and
muscles on the
skeleton
Bone Formation and Growth
Osteoclasts
Bone
destroying
cells
Bone Formation and Growth
Rickets
A disease of children
in which the bones fail
to calcify
Due to lack of calcium
or vitamin D.
(Vitamin D needed to
absorb calcium)
Causes:
Poor nutrition in
poverty areas
Bone Fractures
A fracture is a
break in a
bone
Simple
Bone breaks clean. No broken skin. Closed
Compound
Comminuted
Greenstick
Bone protrudes through skin. Open
Bone breaks in many fragments. Common in
elderly
Bone breaks incompletely. Common in children
Green stick Comminuted
Simple
Compound
Bone Fractures
Fractures
are treated
by reduction
Open
Reduction
Surgical incision. Reduce fracture.
Position bone with pins or wires.
Closed
Reduction
Bones brought back into place by
physician’s hands. Immobilized
with cast
Bone Fractures
Open reduction
and internal
fixation
ORIF
Bone Fractures
Closed
Reduction
Bone Repair
Repair involves 4 events
•A hematoma is formed (bleeding
occurs when bone broken)
•The break is splinted by a
fibrocartilage callus that close
the gap
•The bony callus is formed made of
spongy bone
•A strong and permanent patch is
formed
Axial Skeleton
Divided into 3 parts
Skull
Vertebral column
Thorax
BLUE
Skull
Formed by 2 sets
of bones
Cranium: encloses and
protects the brain
Facial bones: hold
eyes in anterior
position and allow
muscles to show
feelings thru facial
expressions
Skull
Cranium is
made of 8
large flat
bones:
Frontal
1
forehead
1
Skull
Parietal
2
superior
and lateral wall
2
Skull
Temporal
2
inferior to
parietal
4
Skull
Occipital
1 posterior.
Floor and
back wall of
cranium
3
Skull
Sphenoid
1 butterfly
shaped.
KEYSTONE bone.
Floor of cranium.
Full of sinuses
5
5
Sphenoid
Sphenoid
Sella turcica – holds pituitary
P
Skull
Ethmoid
1 anterior to
sphenoid
Forms roof of
nasal cavity and
medial orbits
6
6
Ethmoid
O
Ethmoid
Has
cribiform
plate
Holds
olfactory
receptors
to the brain
Skull
12 parietal
1
11
temporal
frontal
sphenoid 2
3 ethmoid
4
5
10
6
occipital
7
9
8
Facial Bones
Made of 14bones.
12 paired
Maxilla
8
2 upper jaw bone
KEYSTONE BONE
All facial bones except
mandible join this
bone
Facial Bones
Palatine
2 posterior to
maxilla
Hard palate
12
Facial Bones
Palatine
Hard palate
12
Facial Bones
Zygomatic
2
cheek
bones
9
Facial Bones
Lacrimal
2 medial wall of
orbit
Passage way for
tears
11
Facial Bones
Nasal
7
2
nose
Facial Bones
Vomer
1 means “plow”
Median line of
nasal cavity
Forms septum
14
Vomer
14
Facial Bones
Inferior
Concha
2 lateral
wall of
nasal
cavity
13
Facial Bones
Inferior Concha
13
Facial Bones
Mandible
1 lower jaw bone
Largest and
strongest facial
bone
10
Facial Bones
Hyoid
1 only bone that does
not articulate with
another bone
Suspended in mid
neck region
serves as a movable
base for the tongue
Horse-shoe shaped
Cribiform plate
Sphenoid
Sella turcica
Foramen magnum
B
Sagital
Suture
D
E
C
A
glabella
Infra orbital
foreman
F
G
Mental
foramen
Fetal Skull
Contains fontanels
these are fibrous
membranes that have
yet to be converted to
bone.
They connect the
cranial bones.
Also called
Soft spots
1.
Anterior
fontanel
Anterior
fontanel
1.
2.
Posterior
fontanel
2.
Posterior
fontanel
Vertebral Column
Extends from the skull
to the pelvis
Made of 26
irregular bones
Running thru the
central cavity of the
vertebral column is
the spinal cord
Vertebral Column
Cervical
7
neck
Thoracic
12
chest
Lumbar
5
back
Sacrum
5 fused bones
Coccyx
Tailbone 3-5 fused bones
1.
1. cervical
C-4
2.
T-6
2. thoracic
3.
L2
3. Lumbar
4.
Sacrum
5.
Coccyx
4. Sacrum
5. Coccyx
Vertebral Column
Vertebrae are separated
by
Intervertebrael disc
They cushion and
absorb shock
Vertebral Column
Abnormal spine
curvatures:
Can be caused
by congenital,
disease, poor
posture,
unequal muscle
pull
Scoliosis
Lateral curvature
Lordosis
anterior curvature
Kyphosis
posterior curvature
Kyphosis
Lordosis
Scoliosis
1 foramen
3
Atlas
2 Absence
of body
1 Body of vertebrae
3
Axis
2
Odontoid
process
Bony Thorax
Sternum, ribs and thoracic vertebrae
Sternum
Breastbone
Made of 3 parts:
Manubrium
Body
Xiphoid process
Bony Thorax
Sternum, ribs and thoracic vertebrae
Ribs
12
_________
pairs
True ribs
1st 7 pairs
False ribs
5 total
Floating ribs
2 of the 5
1
True rib
manubrium
5
2
body
3
Xiphoid
process
False rib
6
Floating rib
7
4
Intercostal
cartilage