Bone is a living tissue that provides structure and support throughout the body. It can be classified based on shape as long, short, flat, or irregular bones. Long bones are cylindrical with a hollow cavity, while short bones are cube-shaped with no cavity. Flat bones are thin and curved, and irregular bones contain spongy bone covered by compact bone. Bones also develop through two processes and have a mature microscopic structure of compact and cancellous bone.

2.  Bone is a living tissue and one of the hardest




structures of the body.
Provides shape and support to the tooth.
Protects the vital organs of the body.
Storage site for minerals-storage of blood
cells.
Possesses certain toughness and elasticity

3. Classificaion of bones-based on shapelong,flat,irregular
 Long bones-long and slender
 Include bones of arm-humerus,radius,ulna, Leg-femur




tibia, phalanges-individual bones of finger, toe ,palms of
hands and feet(metacarpels and metatarsals).
Posseses a tubular diaphysis or shaft-compact bone at
periphery and a central cavity having yellow marrow.
Ends of the long bones-epiphysis(compact bone at
periphery and spongy bone at centre)
Epiphysis is covered by hyaline cartilage-(cushioning
effect)
Epiphyseal line btw diaphysis and epiphysis

5.  Short bones- cube shaped, consist of spongy bone
surrounded by a thin layer of compact bone.
 Contain bone marrow but no marrow cavity.
 Include bones of wrist-carpals, ankle-tarsals.
 Flat bones- thin, flat, curve with no marrow
cavity,spongy bone present btw upper and lower layer of
compact bone.eg, sternum,clavicle,bones of skull
 Irregular bones- made of spongy bone which is
covered by compact bone.bone marrow but no marrow
cavity,include facial bones(ethmoid, sphenoid),pelvic
bones-pubis ,ischium, mandible

6.  Sesamoid bones- these develop in tendonspressure,tension or friction,eg patella(knee cap)

7. Classification based on developmentendochondral and intramembranous bones
 Endochondrial -Bones formed by replacement of
hyaline cartilage with bone tissue-in trunk and
extremities.
 Intramembranous - replacement of connective tissue
with bone.seen in cranium,facial bones of skull,
mandible,clavicles

8. Classification based on their
microscopic structure- mature,immature
bone
 Mature bone
Compact and cancellous
 Compact-tightly packed osteons or haversian systems in
layers (lamellar bone)
 Cancellous bone (spongy bone)-honeycomb appearance
with large marrow cavities
 Woven(immature bone) first formed bone, seen in
alveolar bone and healing of fractures.