Anatomy Lecturre 6 " BONES " by DR AHMAD QURESHI from the Plateform oF Pharmohubpakistan

1. BONES…
 Dr Ahmad Ali Qureshi
 (MBBS,GMC)

2. Kindly recite DUROOD E
PAK

3. Definition of BONE...
“Bone is the substance that forms the skeleton of the body. It is
composed chiefly of calcium phosphate and calcium carbonate”
FUNCTIONS OF BONE…
The human skeleton serves six major functions
 Support
 Movement
 Protection
 Production of blood cells
 Storage of iron
 Endocrine regulation

4. (1) What are the Bone Regions?
 Axial
 Down the center of body
 Skull, vertebral column, rib cage, center pelvis
 Appendicular
 Off the sides of body
 Upper and lower limbs, shoulder and hip bones

6.  Axial Skeleton (Head + Neck +Trunk)
SKULL 22 Bones
Ear Ossicle (3+3) 6 Bones
Hyoid 1 Bone
Vertebral coloumn 33 Bones
Ribs (12+12) 24 Bones
Sternum 1 bones
Total = 80 Bones
 Appendicular Skeleton (upper lim+lower limb)
Upper limb (Right 32+ Left 32) 64 Bones
Lower limb (Right 31+ Left 31) 62 Bones
Total = 126 Bones
GRAND TOTAL 80+126=206 BONES

7. Developmental Classification
 MEMBraNE BONES…
Bone formed directly in connective tissue, i.e. by intramembranous
ossification, rather than by replacing cartilage (compare cartilage bone). Small
areas of membrane become jelly-like and attract calcium salts
Examples = Some face bones, skull bones, and part of the clavicle
are membrane bones.
 Cartilagenous bobes…
Intracartilaginous ossification • In intra cartilaginous ossification →
cartilaginous model is formed which is closely resemble the bone to be formed.
•This cartilage is subsequently replaced by (not converted into) bone. eg.
Almost all of the long bones.
 Membranocartilagenous BONES…
These bones develop partly in membranes and partly in cartilage.
Example=Occipital,Temporal,sphenoid bones of the skull, mandible, clavicle

8. (2) What are the types of Bones?
 Long
 Short
 Flat
 Irregular

10. (3) Long Bones
 Longer than they are wide
 Has a shaft and 2 ends
 Weight bearing bones (like steel beams)
 Provide the greatest structure and support
 Examples:
 All limb bones
 Except…. Kneecap,Wrist andAnkle bones

12. (4) Short Bones
 Nearly same length,width,thickness but shape irregularly
 Allow for wider range of movement
 Examples:
 Wrist (carpals)
 Ankle (tarsals)

14. (5) Flat Bones
 Thin, flat and curved
 Protect soft tissue (like plates of armor)
 Examples:
 Sternum
 Shoulder blades
 Ribs
 Skull bones

16. (6) Irregular Bones
 Complicated, unusual shapes
 Muscles, tendons, ligaments usually attach to these
 Examples:
 Vertebrae
 Hip bones

18. (8) Bone Structure
 Unique based on location + bone type.
 Compact Bone (Outer Layer):
 Dense
 Smooth and Solid to naked eye
 Spongy Bone (Inner Layer):
 Hole-y (like a honeycomb)
 Made of small needle-like, flat pieces called “trabeculae”
 Open spaces between trabeculae are filled with red or yellow bone marrow

20. (9) Structure of a Long Bone
 Diaphysis:
 Center, main shaft
 Long part of bone
 Made of very thick compact bone surrounding a central marrow cavity
 Epiphysis:
 Ends of bone
 Wider than diaphysis
 Made of compact bone which surrounds spongy bone.
 Joint surface of each epiphysis is covered with hyaline cartilage

21.  Epiphyseal Line:
 Remnant of Epiphyseal Plate
 Found in adult bones
 Shows amount of cartilage growth during adolescence
 Membranes:
 Periosteum =Around the outside
 Richly supplied with nerve fibers, lymphatic vessels and blood vessels
 Provides anchoring points for tendons and ligaments
 Endosteum =Around the inside
 Surrounds the spongy bone

23. (12) Chemical Composition of Bone
 Contains organic & inorganic components
 Organic:
 Cells (osteoblasts, osteocytes, osteoclasts)
 Osteoid
 Made of glycoproteins and collagen fibers
 Secreted by osteoblasts
 “filler matrix” around cells
 Contribute to flexibility and tensile strength
 Inorganic:
 Mineral Salts (calcium phosphates)
 Contribute to hardness of bone (allowing for compression resistance)

24. TO BE CONT….
ThaNk yOU…