Its for education purpose.

1. The Human Skeleton

2. What’s Skeleton ?
• Skeleton: a usually rigid supportive or
protective structure or framework of an
organism.
• Especially : the bony or more or less
cartilaginous framework supporting the
soft tissues and protecting the internal
organs of a vertebrate.
Skeleton includes bones and cartilages. It forms the main supporting
framework of the body, and is primarily designed for a more
effective production of movements by the attached muscles.

3. What is bone?
• Bone is living tissue that makes up the
body's skeleton.
• There are 3 types of bone tissue, including
the following:
• Compact tissue. The harder, outer tissue of
bones.
• Cancellous tissue. The sponge-like tissue
inside bones
• Subchondral tissue. The smooth tissue at
the ends of bones, which is covered with
another type of tissue called cartilage.

4. There are 206 bones in the human skeleton, not
including teeth and sesamoid bones
• 80 axial bones. This includes the head, facial, hyoid,
auditory, trunk, ribs, and sternum.
• 126 appendicular bones. This includes arms,
shoulders, wrists, hands, legs, hips, ankles, and feet.

5. Division of skeleton system.
Regions of the skeleton Number of Bones
AXIAL SKELETON
Skull
• Cranium 05
• Face 14
Hyoid 01
Auditory ossicles (3 in each ear) 06
Vertebral column 26
Thorax
• Sternum 01
• Ribs 24
Total 80

6. Division of skeleton system.
Regions of the skeleton Number of Bones
APPENDICULAR SKELETON
Pectoral Girdle (Shoulder)
• Clavicle 02
• Scapula 02
Upper Extremities
• Humorous 02
• Ulna 02
• Radius 02
• Carpals 16
• Metacarpals 10
• Phalanges 28

7. Division of skeleton system.
Regions of the skeleton Number of Bones
APPENDICULAR SKELETON
Pelvic Girdle (Hip)
• Coxal, pelvic or hip bone 02
Lower Extremities
• Femur 02
• Fibula 02
• Tibia 02
• Patella 02
• Tarsals 14
• Metatarsals 10
• Phalanges 28
Total 126

9. Functions of bones
• Bones provide shape to the body.
• Bones act as a protection to internal organs like brain, heart, lungs
etc..
• Provides support to the body and anchors muscles.
• Bones serve as storage space for minerals like calcium and
phosphate
• Bones helps in facilitating body movements.
• Bones serve as the birthplace for red blood cells.

10. Mechanical function
• Protection. Bones are vital for protecting the
important and fragile organs in the body. For example
bones protect the heart and the brain.
• Structure. Without bones, our body would have no
frame and essentially be an immobile lump of flesh
and tissue.
F
U
N
C
T
I
O
N
O
F
B
O
N
E

11. Mechanical function
• Movement. The bones pair up with the joints,
ligaments, tendons and muscles to allow the body to
move as it does.
• Sound Transduction. Bones are also important for
conduction vibrations which allow us to hear.
F
U
N
C
T
I
O
N
O
F
B
O
N
E

12. Metabolic function
The metabolic functions of the bone are many:
• The bone matrix can store several minerals, chiefly
calcium and phosphorus as well as iron in the form of
ferritin.
• Chondroitin sulfate, a carbohydrate moiety, is also a
commonly found element in the matrices.
F
U
N
C
T
I
O
N
O
F
B
O
N
E

13. Metabolic function
• Specific growth factors, including insulin-like growth
factor or IGF-1, are housed in bone and then released
periodically.
• pH balance is also regulated as bones may alter the
composition of alkaline salts in the serum to maintain
the optimal pH level.
F
U
N
C
T
I
O
N
O
F
B
O
N
E

14. Metabolic function
• Osteocytes can engulf toxic molecules and heavy
metals from the serum as a means of detoxification.
• Fat storage
F
U
N
C
T
I
O
N
O
F
B
O
N
E

15. Classification of Bone
Long Bone Short Bone
Flat Bone
Irregular
Bone
Pneumatic
Bone
Sesamoid
Bone
Accessory
Bone

17. • It formed directly in connective
tissue, i.e. by intramembranous
ossification, rather than by
replacing cartilage
Membrane
bone
• Almost any place where two bones
meet in your body is cushioned by
cartilage. It's also at the ends of all
your bones that form joints
Cartilaginous
bone
• Membrano – cartilaginous
bones ossify partly in membrane
and partly in cartilage. Eg
clavicle, mandible , occipital etc.
Membrano-
cartilaginous
bone

18. 1. Axial
skeleton
• It includes skull,
vertebral column
& thoracic cage.
2. Appendicular
skeleton
• It includes bones
of the limbs.

19. I. Macroscopically
• Macroscopically, the
architecture of bone may be
compact or cancellous
II. Microscopically
• It is of four type, namly
lamellar, fibrous, dentine
and cement.

21. Gross anatomy of long bone
• The structure of a long bone
allows for the best
visualization of all of the parts
of a bone.
• A long bone has two parts:
the diaphysis and
the epiphysis.
• The diaphysis is the tubular

22. Gross anatomy of long bone
• The hollow region in the
diaphysis is called
the medullary cavity, which
is filled with yellow marrow.
• The walls of the diaphysis are
composed of dense and
hard compact bone.

23. BLOOD SUPPLY OF THE LONG BONE
The nutrient artery supplies
directly from major systemic
arteries. It enters the long bone
through the nutrient foramen. It
then divides into ascending and
descending branches. These
branches gives of smaller
parallel arteries called the radial
branches

24. • THE METAPHYSEAL ARTERY
• Metaphyseal arteries arising from the anastomosis around the
joint enters the metaphysis at the margin of the capsule
attachment. These anastomose with the spiral arteries making
the metaphysic the most vascular area of the long bone
• THE EPIPHYSEAL ARTERY
• Epiphyseal arteries are derived from periarticular vascular
arcades. The epiphysis has openings that allows arteries to go in
and out.
• THE PERIOSTEAL ARTERY
• The periosteum has rich blood supply from the blood vessels
that anastomose beneath the periosteum.
BLOOD SUPPLY OF THE LONG BONE

25. What is cartilage?
C
A
R
T
I
L
A
G
E
Cartilage is a strong, flexible connective
tissue that protects your joints and
bones. It acts as a shock absorber
throughout your body.

27. Clinical aspects
• Common bone diseases often affect the bone density, e.g. in
young children due to malnutrition. For example, rickets is a
bone deformity seen in young children who lack vitamin D.
Their legs are disfigured and they have trouble walking. The
damage is irreversible though surgery may help.
• Osteomalacia and osteoporosis are diseases seen mainly in
adulthood.

28. • Osteomalacia is the improper mineralization of bone due to a
lack of available calcium and phosphate. The bone density
decreases and the bones become soft. Osteoporosis has been
noted in all ages but mostly in postmenopausal and elderly
women. A progressive decrease in bone density increases the
risk of fracture. Patients who are on long-term steroid
medication are in particular risk.