The Axial Skeleton
Access Human Biology.
Clare Hargreaves-Norris
Task
Label the
diagram
of the
skeleton
Clare Hargreaves-Norris
Introduction
The skeleton is divided into two parts:
 The axial skeleton
 The appendicular skeleton
The axial skeleton is made up of 80 bones
comprising of the skull, rib cage and vertebral
column. We will now look in detail at each section
(see separate presentation for the skull).
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The Vertebral Column
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The vertebral column is made up of 33
individual bones, though some are fused
together.
In-between each vertebrae is a pad of fibrous
tissue called a disc.
These discs act as shock absorbers to protect
against gravity and injury.
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Functions Of The Vertebral Column
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Protects the spinal cord – each vertebrae
contains a hole in the centre through
which the spinal cord runs.
Provides attachment for the ribs
Provides attachment for the muscles
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Cervical Vertebrae
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The first seven vertebrae
are called the cervical
vertebrae.
At the top of the spinal
column, these bones form a
flexible framework for the
neck and support the head.
The first cervical vertebrae
is called the atlas and the
second is called the axis.
The atlas shape allows the
head to nod and the axis
allows the head to shake.
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Thoracic Vertebrae
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The next twelve vertebrae
are called the thoracic
vertebrae.
These are found in the
upper back.
These bones move with the
ribs to form the rear
anchor of the ribcage.
Thoracic vertebrae are
larger than cervical
vertebrae and increase in
size from top to bottom.
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Lumbar Vertebrae
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The lumbar vertebrae are
situated in the lower back.
These five bones are the
largest vertebrae in the
spinal column.
They support most of the
body's weight and many of
the back muscles attach to
the lumbar vertebrae.
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The Sacrum
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The sacrum is a triangular
bone located just below
the lumbar vertebrae.
It consists of five sacral
vertebrae in a child, which
become fused into a single
bone after age 26.
The sacrum forms the rear
wall of the pelvic girdle.
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The Coccyx
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The bottom of the
spinal column is called
the coccyx or tailbone.
It consists of 4 bones
that are fused
together in an adult.
Many muscles connect
to the coccyx.
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Curves
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When looked at from the
side, the spine forms four
curves.
These curves are called
the cervical, thoracic,
lumbar, and pelvic curves.
These curves allow human
beings to stand upright
and help to maintain
balance.
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Ribs
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The ribs are thin, flat, curved
bones that form a protective
cage around the organs in the
thorax.
There are 24 bones arranged
in 12 pairs.
The ribs form a cage that
encloses the upper body.
The ribs protect the heart
and lungs from injuries and
shocks.
The ribs also protect parts of
the stomach, spleen, and
kidneys.
Ribs help you to breathe.
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Sternum
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The sternum is a flat,
dagger shaped bone
located in the middle of
the chest.
Along with the ribs, the
sternum forms the rib
cage.
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The Appendicular Skeleton
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Human Biology
Clare Hargreaves-Norris
Introduction
The skeleton is divided into two parts:
 The axial skeleton
 The appendicular skeleton
The appendicular skeleton is made up of
126 bones comprising of the arms, legs,
pelvic girdle and shoulder girdle.
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Clavicle
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There are two
clavicles, more
commonly known as
the collar bones.
These slender bones
run from the shoulder
to the breast bone,
below the neck.
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Scapula
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The two shoulder
blades are situated in
the upper back.
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Humerus
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The bone of the upper
arm, one located in
each arm.
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Radius and Ulna
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The radius runs from
the elbow to the
thumb side of the
forearm.
The ulna runs from
the elbow to the little
finger side of the
forearm.
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Carpals, Metacarpals and Phalanges
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The 16 carpal bones (8
in each) make up the
bones of the wrist.
There are 5
metacarpal bones in
each hand.
There are 28
phalanges that make
up the fingers.
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Pelvic bones
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There are two bones that form the
pelvic girdle.
The pelvic girdle supports the weight
of the body, protects and supports
pelvic organs including: the bladder,
the reproductive organs, and the
developing fetus in a pregnant woman.
The pelvic girdle differs between men
and woman.
In a man, the pelvis is larger and the
iliac crests are closer together.
In a woman, the pelvis is more
delicate and the iliac crests are
farther apart to allow for the
birthing process.
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Femur and Patella
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There are two femur
bones, one in each
upper leg.
The patella is the knee
cap.
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Tibia and Fibula
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The tibia is one of the
bones of the lower leg
and runs medially to
the big toe side of the
leg.
The fibula is the
lateral bone of the
lower leg.
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Tarsals, Metatarsals and Phalanges
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There are 14 tarsal
bones (7 in each ankle)
that collectively form
the ankle.
There are 5
metatarsal bones in
each foot.
There are 28
phalanges that make
up the toes.
Clare Hargreaves-Norris