Skeletal System
Part B
Skeletal System
Part B
VERTEBRAL
COLUMN
VERTEBRAL
COLUMN
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Extends from the skull to the pelvis and
protects the spinal cord.
It is composed of a vertebrae separated by
intervertebral disk.
An infant has 33 vertebral bones and an
adult has 26
The vertebral bones have 4 curvaturesCervical, thoracic, lumbar, and pelvic.
VERTEBRAL
COLUMN
Vertebra
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A Typical Vertebra
All vertebrae have a
common structural
pattern. Each
vertebra consists of a
body, vertebral arch,
vertebral foramen and
vertebral canal.
Vertebra
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Cervical Vertebrae (7)
C1 and C2 are the smallest and are
unusual. Often called the atlas and the
axis
They have no intervertebral disc
between them and are highly modified.
The dens of the axis (2nd vertebra)
provides a pivot for the atlas when the
head is turned from side to side.
C1 has no spinous process nor body.
Vertebra
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Cervical Vertebrae
(7)
The remaining cervical
vertebra help to make
up the neck.
Vertebra
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Thoracic Vertebrae
(12)
Larger than the
cervical
Slope downward and
faces the sides of
bodies articulate with
the ribs
Vertebra
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Lumbar Vertebrae
(5)
Large and strong
Sacrum
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Vertebra
Starts as 5 bones but
fuses together
between 18-30
Triangular structure that
bears rows of dorsal
sacral foramina
United with coxal bones
at the sacroiliac joints.
Provides a guide for
determining the size of
the pelvis.
Sacrum
Vertebra
Coccyx
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Composed of 4 bones
that fuse together by
age 25
Forms the lowest part
of the vertebral
column
Acts a shock absorber
when a person sits.
THORACIC CAGE
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Includes the ribs,
thoracic vertebrae,
sternum, and costal
cartilages
It supports the
shoulder girdle and
upper limbs, protects
viscera, and functions
in breathing.
THORACIC CAGE
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RIBS
12 pairs of ribs are attached
to the 12 thoracic vertebrae
First 7 rib pairs are called
true ribs, join the sternum
directly by their costal
cartilages.
Remain 5 pairs called false
ribs, their cartilages do NOT
reach the sternum directly.
THORACIC CAGE
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RIBS
In fact the first 3 of the false ribs join the
cartilage of the 7th true rib.
The remain two ribs are called floating ribs,
because they have no attachment to any
cartilage.
Typical rib has a shaft, head, and tubercle
that articulate with the vertebrae.
THORACIC CAGE
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Sternum is a flat
elongated bone that
develops in three
parts- an upper
Manubrium, a
middle body, and a
lower xiphoid
process.
Articulates with costal
cartilages and
clavicles.
PECTORAL GIRDLE
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Composed of 2 clavicles
(collar bone) and 2
scapulae (shoulder
blades)
It forms an incomplete
ring that supports the
upper limbs and provides
attachments for muscles
that move the upper
limbs
PECTORAL GIRDLE
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CLAVICLE
Rodlike bones that run horizontally between the
sternum and shoulders.
Hold shoulders in place and provide attachments
for muscles.
Has a medial (sternal) end and a lateral (acromial
ends)
PECTORAL GIRDLE
PECTORAL GIRDLE
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SCAPULA
Broad, triangular bones
Articulate with the humerus of each limb and provides
attachment for muscles of the upper limbs and chest.
Has a Acromion process that forms the tip of the shoulder
A Coracoid process that curves anteriorly and inferiorly to
the clavicle.
Has a Glenoid cavity, it articulates with the head of the
arm bone (humerus).
UPPER LIMBS
 Provide
the frameworks and
attachments of muscles, and
function in levers that move the
limb and its parts.
UPPER LIMBS
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Humerus-extends from scapula to
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Radius-Located on thumb side of the
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Ulna-Longer than radius and overlaps the
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Hand- Has a wrist, palm, and 5 fingers
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elbow.
forearm between elbow and wrist
humerus posteriorly.
8 carpals that form a carpus, 5
metacarpals, and 14 phalanges.
HUMERUS
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Its upper end has a smooth round head that fits
into the glenoid cavity.
Below the head are two processes a greater
tubercle on the lateral side and a lesser
tubercle on the anterior side.
Near the middle of the bony shaft on the lateral
side is a rough V-shaped area called the deltoid
tuberosity.
On the bottom section of the humerous are
Epicondyles which provide attachments for
muscles and ligaments of the elbow. (medial
and lateral)
HUMERUS
HUMERUS
Radius
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Radius-Located on thumb side of the forearm
between elbow and wrist.
Shorter than the ulna
A thick-disklike head at the upper end
On the radial shaft just below the head is a
process called the radial tuberosity. An
attachment for muscles.
At the distal end of the radius, a lateral styloid
process provides attachments for ligaments of
the wrist.
Ulna
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Longer than radius and overlaps the
humerus posteriorly.
A Medial Styloid process at the distal
end of the ulna proves attachemnts for
ligaments of the wrist.
The Ulna also has a head…on the
opposite side as the radius
Styloid Process
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Remember….when thinking of
medial/lateral processes…you must put
your arms in the correct anatomical
position! 
Radius and Ulna
Wrist and Hand
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The wrist joint is at the junction of the
forearm and the hand. The skeleton of
the wrist consists of 8 small carpal bones
that are firmly bound in two rows of four
bones each. The resulting compact mass
is called a carpus.
Wrist and Hand
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Hand- Has a palm, and 5 fingers.
Five metacarpals bones, one in line with each
finger, form the framework of the palm. These
bones are cylindrical, with rounded distal ends
that form the knuckles of clench fist. These
bones are numbered 1-5 beginning with the
metacarpal of the thumb.
Wrist and Hand
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Hand- Has a palm, and 5 fingers.
Phalanges are the finger bones. There are
three in each finger. A proximal, a
middle, and a distal phalanx and two in
the thumb.
Wrist and Hand
PELVIC GIRDLE
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The PG consists of 2
coxal bones (hipbones)
that articulate with each
other anteriorly and with
the sacrum posteriorly.
Along with sacrum and
coccyx they form the
pelvis.
Provides support for the
weight, and attachments
for muscles, and protects
visceral organs.
PELVIC GIRDLE
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Each coxae (hipbone) develops from three
key parts. An ilium, an ischium, and a
pubis.
These parts fuse in the region of a cupshaped cavity called acetabulum.
This depression, on the lateral surface of
the hipbone receives the rounded head of
the femur.
PELVIC GIRDLE
 Illium-
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largest portion of the coxal bone,
flares outward, forming the prominence of
the hip.
The margin of the prominence is called
the Iliac Crest.
Joins the sacrum at sacroiliac joint
PELVIC GIRDLE
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Ischium- Lowest
portion of the coxa
bones.
L-shaped.
PELVIC GIRDLE
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Pubis- constitutes the
anterior portion of the
coxa.
The two pubic bones
come together at the
midline to form a joint
called the smyphysis
pubis.
The angle these bones
form below the
symphysis is the pubic
arch.
PELVIC GIRDLE
COXA(E)
PELVIC GIRDLE
Greater and Lesser Pelvis
 Below
the pelvic brim; greater
pelvis is above it
 Lesser pelvis functions as a birth
canal; Greater pelvis helps
support abdominal organs.
PELVIC GIRDLE
Difference: Male/Female
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Female: Tilted forward, adapted for childbearing,
cavity of the true pelvis is broad, shallow, and has
a greater capacity.
Bones are lighter, thinner, and smoother
The acetabula are smaller and farther apart
The pubic arch is broader and more rounded.
The sacrum are wider, shorter, sacral curvature is
accentuated.
The coccyx more movable and much straighter.
PELVIC GIRDLE
Difference: Male/Female
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Male: Tilted less far forward, adapted for support
of a male’s heavier build and stonger muscles;
cavity of the true pelvis is narrow and deep.
Bones are heavier and thicker; and markings are
more prominent
The acetabula are larger and closer together.
The pubic arch is more acute.
The sacrum is narrow; longer;
The coccyx less movable and curves ventrally.
LOWER LIMBS
 Provide
the frameworks of
the thigh, leg, and foot.
FEMUR
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FEMUR- Extends from
the hip to knee;
Longest bone in the
body.
A large, rounded
head at its proximal
end which projects
medially into the
acetabulum of the
coxal bone
FEMUR
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Just below the head are a
constriction, or neck and
two large processes.
A greater trochanter and
a lesser trochanter.
These processes provide
attachments for muscles of
the lower limbs and
buttocks.
FEMUR
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•
At the distal end of the femur are two rounded
processes, the lateral and medial condyles,
articulate with the tibia of the leg.
On the medial surface at its distal end is a
prominent medial epicondyle, and on the
lateral surface is a lateral epicondyle. These
projections provide attachments for muscles and
ligaments.
FEMUR
FEMUR
PATELLA
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Flat seasamoid bone located in a tendon
that passes anteriorly over the knee.
Controls the angel of this tendon and
functions in lever actions associated with
lower limbs movement.
PATELLA
TIBIA
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AKA- Shin Bone,
Larger of the two leg
bones.
Located on the medial
side of the leg
TIBIA
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Its proximal end is expanded into medial and
lateral condyles.
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Below the condyles on the anterior surface is a
process called the tibial tuberosity.
At its distal end, the tibia expands to form a
prominence on the inner ankle called the
medial malleolus, which is an attachment for
ligaments. (Its lateral cousin is on the fibula).
Fibula
A
long slender bone located on
the lateral side of the tibia.
 Ends are slightly larger, with a
proximal head and a distal
lateral maleolus.
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The foot is an
amazing and
intricate structure.
The bones in your
feet make up about
one-fourth of all the
bones in your body.
Each foot contains
26 bones. It takes
33 joints, 107
ligaments, 19
muscles and
numerous tendons
to hold the bones in
place and to move in
a variety of ways.
Ankle and Foot
Ankle and Foot
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In addition, each
foot has about
125,000 sweat
glands that excrete
as much as a half a
pint of moisture
each day.
Ankle and Foot
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Consists of an tarus, a
metatarsus, and five
toes.
The tarsus is
composed of seven
tarsal bones. These
bones are arranged
so that one of them,
the talus, can move
freely.
Ankle and Foot
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The largest of the tarsals, the calcaneus or
heel bone. It helps to support the weight
of the body and provides an attachment
for muscles that move the foot.
Ankle and Foot
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The metatarsus
consists of five
elongated metatarsal
bones.
They are numbered
1-5, beginning on the
medial side.
Ankle and Foot
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The phalanges of the toes
are shorter, but otherwise
similar to those of the
fingers, and align, and
articulate with the
metatarsals.
Each toe has three
phalanges, a proximal, a
middle, and distal
phalanx- except the big
toe which only has the
first two.

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How well can
you do?
On a scrape
piece of
paper take
this mini-quiz!

How did you
do???