1. axial & appendicular skeleton 2. long & short bone 3. Periosteum Anatomical basis for Medicine/Dentistry/Health Sciences students.

1. Dr S M Niazur Rahman
Anatomy Unit, Faculty of Medicine
Anatomy: BONES
ANATOMY L-07: MBBS B 21: ELEMENT-1: 05.11.2015

2. Learning outcomes
• 7.1 Describe the component of axial & appendicular
skeleton
• 7.2 Outline the types, form & architecture of bones
• 7.3 Compare the axial & appendicular skeleton
• 7.4 Explain the structure of long & short bone
• 7.5 Outline the parts of growing long bone
• 7.6 Outline the blood supply of a bone
• 7.7 Discuss the structure & function of periosteum

3. The Human Skeleton

4. Bones
• Bones are highly vascular, constantly changing,
mineralized form of specialized connective tissue.
• Bones are developed from cartilages.
• Covered by Periosteum- a fibro-vasculo-celluar
membrane; all around except the articular surfaces.
• 206 named bones in human body

5. 1. Support:
• The bones of the legs, pelvic girdle, and
vertebral column support the weight of the erect
body.
• The mandible supports the teeth.
• Other bones support various organs and tissues.
2. Protection:
• The bones of the skull protect the brain.
• Ribs and sternum (breastbone) protect the lungs
and heart.
• Vertebrae protect the spinal cord.
Bones-functions

6. 3. Movement:
• Skeletal muscles act on the bones to move the
body.
4. Reservoir for minerals and adipose tissue:
• 99% of the body’s calcium & 85% of
phosphorous is stored in bone.
• Adipose tissue is found in the marrow of certain
bones.
5. Hematopoiesis:
• Blood cell formation.
• All blood cells are made in the marrow of bones.
Bones-functions

7. Classification of Bones

8. According to location:
Classification of Bones
Axial Skeleton Appendicular Skeleton

9. According to structure:
Classification of Bones
1. Compact bone 2. Spongy or Cancellous bone

10. According to shape:
Classification of Bones
1. Long bone
2. Short bone
3. Flat bone
4. Irregular bone

11. Long bone:
• Length is more than the
width.
• Transmits body weight.
• Have medullary cavity.
• Consist of a shaft
(diaphysis) and two
expanded ends (epiphysis)
for articulation.
• Example:
Humerus, Tibia etc.
Classification of Bones

12. Long bone: Features
Classification of Bones
• The diaphysis has a thick wall made of
compact bone surrounding a central cavity
(medullary cavity) containing yellow marrow
(fat).
• The epiphyses are covered by a thin layer of
compact bone. Their interior contains
spongy bone and red marrow. The outer
surface (articular portion) of the epiphysis is
covered by hyaline cartilage.
•
• Epiphyseal line is a thin plate of hyaline
cartilage separating the epiphyses from the
diaphysis, exists only in young growing long
bones and allows them to grow in length.
• Metaphysis are the epiphyseal ends of the
diaphysis

13. Long bone: Features
Classification of Bones
• The long bone is entirely
covered by the
periosteum except where
the articular cartilage
coats the epiphysis.
• The endosteum covers
the surface of the
medullary cavity, the
trabeculae of the spongy
bone.

14. Short bone:
• Are short/cube like.
• Do not have medullary cavity.
• Made of spongy bone.
• e.g. carpal & tarsal bones.
Classification of Bones

15. Flat bone:
• Are flat, plate like & thin.
• No medullary cavity.
• Made of a layer of spongy bone sandwiched
between two layers of compact bone.
• e.g. Sternum, ribs and most bones of the skull.
Classification of Bones
Sternum
Parietal

16. Irregular bone:
• Irregular shape that fit none of the 3 previous
types.
•Made of spongy bone enclosed by a thin crust of
compact bone tissue. No medullary cavity.
• e.g. Vertebrae, facial bones etc.
Classification of Bones

17. Classification of Bones

18. How many bones are there in human body? 206
What about the heart?

19. Bones composed of:
• 35% collagen, ground substance and cells
• 65% inorganic calcium (Calcium hydroxyapatite
crystal)
Composition of Bones

20. Bone cells:
1. Osteoblasts: Bone forming cells
2. Osteocytes: Mature bone cells
3. Osteoclasts: Bone removing cells
Composition of Bones

21. Structure of Bones
• A dense, solid outer layer known as compact
bone.
• An inner layer of spongy bone – a
honeycomb of flat, needle-like projections
called trabeculae.

22. - Lamella: circumferntial & interstitial
- Lacuna: Contain osteocytes
- Canaliculi: Communicating channels through osteocytic process
- Haversian canal: Surrounds blood vessels & nerves
Structure of Bones (Histology)…
Fig: Haversian System

23. Parts of a growing long bone
1. Diaphysis
2. Metaphysis
3. Epiphysis
4. Epiphyseal plate

24. • Long Bones– derived from
1. Nutrient artery
2. Periosteal artery
3. Epiphysial artery
4. Metaphysial artery
Blood supply of Bones

25. • A double layered membrane
covering the external surface of
the entire bone except for the
joint surfaces of the epiphyses.
• Periosteum is richly supplied
with nerve fibers, lymphatic
vessels and blood vessels.
• Structure: 2 layers -
• Outer fibrous layer made of
dense irregular connective
tissue.
• Inner cellular layer contains
osteoprogenitor cells and
osteoblasts.
Periosteum

26. • Internal bone surfaces are covered with a delicate
connective tissue membrane known as the
endosteum.
• The proper healing of a fracture depends on the blood
supply and cellular components of the periosteum and
endosteum.
Endosteum

27. Ossification
This is the process of bone formation.
• Intra-membranous ossification: Bone develops
from a fibrous membrane (formed by
mesenchymal cells). e.g. Flat bones.
• Intra-cartilagenous ossification: Bone forms by
replacing hyaline cartilage. e.g. Long bones.
Sesamoid bone: develops from tendon. e.g. Patella

28. Learning outcomes
• 7.1 Describe the component of axial & appendicular
skeleton
• 7.2 Outline the types, form & architecture of bones
• 7.3 Compare the axial & appendicular skeleton
• 7.4 Explain the structure of long & short bone
• 7.5 Outline the parts of growing long bone
• 7.6 Outline the blood supply of a bone
• 7.7 Discuss the structure & function of periosteum

30. Bone tissue can be described as ________.
A. dead calcified tissue
B. cartilage
C. the skeletal system
D. dense, hard connective tissue
Which category of bone is among the most numerous
in the skeleton?
A. long bone
B. sesamoid bone
C. short bone
D. flat bone
Bone is somewhat flexible due to the presence of
A. hydroxyapatite
B. collagen
C. calcium
D. phosphates

31. Which of these features indicates that a bone is not mature?
A. medullary cavity
B. spongy bone
C. articular cartilage
D. epiphyseal plate
Most of the bones of the arms and hands are long bones;
however, the bones in the wrist are categorized as…..
A. flat bones
B. short bones
C. sesamoid bones
D. irregular bones
Sesamoid bones are found embedded in…….
A. joints
B. muscles
C. ligaments
D. tendons

32. Long bones enable body movement by acting as a …..
A. Counter weight
B. resistive force
C. lever
D. fulcrum
Articular cartilage is found …….
A. at the ends of the epiphysis
B. on the outside of the diaphysis
C. within the epiphyseal plate
Cells that induce this absorption of calcium ions into
the bloodstream are the "bone destroying cells"
called...
A. osteoblasts
B. osteoclasts
C. osteocytes

33. Ligaments and tendons connect to which part of bone
material?
A. endosteum
B. epiphysis
C. periosteum
Which of the following is the growing line or growth
zone or growth plate of the long bones?
A. epiphysis
B. diaphysis
C. metaphysis
The ends of long bones are called the __________.
A. epiphyses
B. diaphyses
C.metaphyses