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Skeletal System
Chapter 5
cranium
mandible
sternum
humerus
carpals
metacarpals
Functions of the Bone

Support


Form the internal framework for the body
Protection

Protect soft body organs


Movement


Skeletal muscles, attach to skeleton by tendons, use the
bones to move the body
Storage


Example – Ribs and skull
Fat and calcium is stored in bones
Blood cell formation

Occurs in bone marrow
Classification of Bones



Adult skeleton has 206 bones.
Compact bone – dense and looks smooth
and homogenous
Spongy bone – Composed of small
needlelike pieces of bone and lots of open
spaces
Classification of Bones (cont.)

Four different shapes of bone

Long bones – longer than they are wide
Classification of Bones (cont.)

Short bones – cube-shaped and contain mostly
spongy bone
Classification of Bones (cont.)

Flat bones – thin, flattened, and usually curved
Classification of Bones (cont.)

Irregular bones – bones that don’t fit one of the
preceding categories
Classification of Bones (cont.)

Skeleton system is divided into two
categories

Axial skeleton – bones that form the longitudinal
axis of the body


Cranium and vertebral column
Appendicular skeleton – bones of the limbs
Structure of a Long Bone

Diaphysis – shaft of bone



Periosteum – covers the
diaphysis
Epiphysis – the ends of the
long bone


Made of compact bone
Filled with spongy bone
Articular cartilage – covers the
external surface of the
epiphysis
Structure of a Long Bone (cont.)


Epiphyseal plate – cause
the lengthwise growth
of the long bone
Epiphyseal line – replaces
the epiphyseal plate after
puberty
Structure of a Long Bone (cont.)

Yellow marrow stores
adipose tissue

Found in the diaphysis


Made of compact bone
Red marrow produces
blood

Found in the epiphysis

Made of spongy bone
Bone Fractures

Simple or closed


Bone breaks clearly
but does not penetrate
the skin
Compound or open

Broken ends of the bone
protrude through soft
tissues and the skin
Simple Fracture or Compound Fracture?
Bone Fractures (cont.)

Comminuted


Bone breaks into many fragments
Common in geriatrics with brittle bones
Bone Fractures (cont.)

Compression

Bone is crushed
Bone Fractures (cont.)

Depression


Broken bone portion is pressed inward
Common fracture in skull
Bone Fractures (cont.)

Impacted

Broken bone ends are forced into each other
Bone Fractures (cont.)

Spiral


Excessive twisting forces bone to break
Common sports fracture
Bone Fractures (cont.)

Greenstick


Bone breaks incompletely, much in the way a
green twig breaks
Common in children
Repairing Bone Fractures

Week 1


Blood vessels are
ruptured when bone
breaks.
Hematoma is formed

Blood-filled swelling
Repairing Bone Fractures (cont.)

Weeks 2-3



New blood vessels
form.
Hematoma hardens
forming fibrocartilage
callus (or soft callus).
Fibrocartilage callus
(made of some bone
and cartilage) forms
over the break.
Repairing Bone Fractures (cont.)

Weeks 4-16


The fibrocartilage
callus ossifies
(or hardens)
becoming spongy
bone.
This forms a bony
callus (or hard callus).
Repairing Bone Fractures (cont.)

Weeks 17 and more


Bony callus is
remodeled so that it
forms a “patch” over
the break.
The “fixed” part of the
bone will be the
strongest part.
Vomer
Skull Anatomy Tutorial Website

http://www.gwc.maricopa.edu/class/bio201/sk
ull/skulltt.htm
Infant Skull



Fontanel – soft spot
Skull is cartilaginous
and hardens as an
infant ages
As an individual grows,
fontanels fuse to form
sutures
Vertebral Column

Cervical – neck



Thoracic – chest




5 vertebrate
L1 – L5
Sacrum


12 vertebrae
T1 – T12
Lumbar – lower back


7 vertebrae
C1 – C7
5 fused vertebrae
Coccyx – tail bone

4 fused vertebrae
Vertebral Column

Atlas – C1


Supports weight of the
skull
Axis – C2

allows the head to turn
Vertebral Column


Vertebral foramen – canal through which the
spinal cord passes
Anterior landmark

Body – Weight-bearing part of the vertebra that
contains a disk
Vertebral Column

Posterior landmarks

Vertebral arch – arch formed from the joining of all
posterior extensions



Transverse processes – two lateral projections
Spinous process – single projection arising from the
posterior aspect of the vertebral arch
Superior and inferior articular processes – paired
projections lateral to the vertebral foramen, allowing a
vertebra to form joints with adjacent vertebrae


Foramen – an opening, or orifice, in a bone
Articular – pertaining to a joint
Vertebral Column
Vertebral arch
Vertebral Column
Superior articular process
Inferior articular process
Vertebral Column

Spinal problems


Bulging disk - extends
outside the space it
should normally occupy
Herniated disk - results
when a disk ruptures
http://www.mayoclinic.com/health/bulging-disk/AN00272