Human Osteology

1. INTRODUCTION TO HUMAN
OSTEOLOGY
PART-2
Madeby: Dr Pankti Patel
M.Sc. Forensic Odontology
Volunteer at Applied Forensic
Research Sciences

2. CONTENTS
 Structure of bone
 Bone cells
 Development and ossification of bone

3. Structure of Bone
 MACROSCOPIC STRUCTURE-
1) Compact bone - hard and dense.
Contains no bone marrow space
2) Cancellous bone –spongy trabecular
framework arranged in definite
pattern to resist stress.
Contains bone marrow.
Image ref. : www.futurelearn.com

4. Image ref.- www.ibiologia.com

5.  MICROSCOPIC STRUCTURE-
 Bone is made up of numerous cylindrical units called
Haversian system/ osteon.
Haversian
canal
Lacunae
Lamellae Canaliculi

6.  Haversian canal- Canal present in the center of system. Runs
parallel to long axis of bone. Each canal contains artery, vein,
nerve and lymphatics with supporting areolar tissue.
 Lamellae- Thin bone tissue containing ground
substance/matrix/collagen fibres arranged concentrically around
the canal.They are interconnected with fibres.
1) Interstitial lamellae- Lie at angular interval between Haversian
system. Run in various directions.
2) Circumferential lamellae- Found over inner and outer periphery
of cortex.
 Lacunae- Spaces between lamellae. Each contains bone cell.
 Canaliculi- Fine radiating channels that connects lacunae with
central Haversian canal. Contain protoplasmic process of bone
cells.

7. Image ref.- Pearson education

8. Bone Cells
 Mainly three bone cells. All are derived from osteogenic cells
but have different functions.
OSTEOBLAST
-Ovoid with
basophilic cytoplasm
-Responsible for
active bone
formation
-Form protein of
matrix and control
mineralization
-Contain Alkaline
Phosphatase.
OSTEOCYTE
-Osteoblast change
into osteocyte by
developing matrix
around itself.
-Become dormant
when active bone
formation is not
required.
-They will occupy
lacunae.
OSTEOCLAST
-Large
multinucleated cells
with acidophilic
cytoplasm.
-Responsible for
bone resorption and
remodelling.
-Contain acid
phosphatase.

9. Image ref.- NewsMedical

10. Development and ossification
of bone
 Bones are mesodermal in origin. They develop from the
embryogenic mesenchyme (loose connective tissue with
fluid matrix).
BONE FORMATION
Endochondrial
-Bone develops by replacing cartilage
-Almost all bones of the skeleton
-Vertebrae
-Pelvis
-Long irregular bones
- Base of skull
Except CLAVICLE
Intramembranous
-Bone develops from fibrous membrane
-Responsible for growth of short bones and
thickening of long bones
-Cranial skull bones, maxilla, mandible
-Flat bones
-Clavicle

11. Image ref.- Dupard, S. J., Grigoryan, A., Farhat, S., Coutu, D. L., & Bourgine, P. E. (2020). Development of Humanized Ossicles: Bridging the Hematopoietic
Gap. Trends in Molecular Medicine, 26(6), 552–569. https://doi.org/10.1016/j.molmed.2020.01.016