OSTEOLOGY

• Study of bones

Composition of Bones

• 30-35% organic framework is made up of protein collagen and polysaccharide - GAG/ glycosaminoglycan which contain chondroitin sulfate.

• 65-70% inorganic framework : 

1. CaPO4 (Calcium orthophosphates) - 80%

2. CaCO3 - Calcium carbonate 

3. MgPO4 (Magnesium phosphate) - 20%

Function of Bones:

1. Movement of skeletal framework

2. Support skeletal muscles

3. Production of calcium and phosphorus minerals, under influence of hormones: calcitonin ( increases blood calcium) and pth/ parathormone (decreases blood calcium).

4. Blood cell formation in the bone marrow

Regions of Long Bones

COMPARATIVE

Regions of Long Bones:

1. Diaphysis - cylindrical shaft

2. Epiphysis - the greater 2 expanded extremities.

3. Metaphysis - junction between the epiphysis and diaphysis.

4. Epiphyseal plate - formed by the hyaline type cartilage.

Internal Parts of Long Bones:

1. Periosteum - outer lining of bone.

2. Endosteum - inner lining of bone

3. Medullary Cavity - the space that houses the bone marrow

• bone marrow - site for hematopoiesis. 

4. Compact bone - located at the diaphysis/ shaft of the bone.

• hard bone tissue.

• solid between periosteum and endosteum.

5. Nutrient foramen - perforation or opening where nutrients enter the bone marrow.

6. Cancellous bone - located at the region of metaphysis.

• soft spongy bone tissue.

Classification of Bones as to Shapes and Functions

1. Long bones- as levers; w/ epiphysis and diaphysis.

• humerus, femur, radius, ulna, tibia, fibula.

2. Short bones - diffuse concussions

• carpals and tarsals.

3. Flat bones - protective function; muscle attachment.

• scapula, os coxae.

4. Irregular bones - have irregular shapes.

• For support and ligament attachment.

• Vertebrae, bones at base of skull.

5. Pneumatic or hollow bones connected to birds’ respiratory systems. 

• humerus, clavicle, sternum

6. Sesamoid bones - resemble sesame seed (patella/ kneecap - largest)

Divisions of the Skeletal Systems

1. Axial Skeleton - bones along the longitudinal axis.

• skull, vertebral column, ribs, sternum

2. Appendicular skeleton - the bones of appendages.

1. Anterior limbs:

• Shoulder girdle: scapula, clavicle, coracoid

• Arm: humerus

• Forearm: radius, ulna

• Manus: carpals, metacarpals, phalanges

2. Posterior limb: 

• Pelvic girdle: os coxae : ilium, ischium, pubis

• Thigh: femur w/ patella distally

• true leg/ crus: tibia, fibula

• pes: tarsals, metatarsals, phalanges

3. Splanchnic skeleton

• bones in viscera/ soft internal organs

1. os penis/ baculum - penis of dog

2. os cordis - heart of ox

3. os rostri - snout of pig

4. entoglossal bone  - skull of chicken