Chapter 6: Osseous Tissue and Bone Structure
o .
The Skeletal System
Skeletal system components
o Bones (~206 total)
Divisions
1. Axial skeleton (126 bones)
Bones of skull, thorax, and vertebral column
Form longitudinal axis of body
2. Appendicular skeleton (80 bones)
Bones of the limbs and girdles that attach them to
the axial skeleton
o Associated cartilages
o Ligaments and other connective tissues
Functions of the skeletal system
o Support
Structural support for body
Framework for attachment of soft tissues and organs
o Storage of minerals and lipids
Concentrations of calcium and phosphate ions in the blood must
be maintained
o Calcium most abundant mineral in body
o Calcium salts in bone act as mineral reserve
Adipose tissue in bones stores lipids
o Blood cell production
Red bone marrow (filling internal cavities of many bones) is
production site for all formed elements of blood
o Protection
Skeleton protects delicate tissues and organs
o Ribs protect heart and lungs
o Skull protects brain
o Vertebrae protect spinal cord
o Pelvis protects digestive and reproductive organs
o Leverage
As levers, bones change magnitude and direction of skeletal
muscle forces
Produce movements ranging from delicate fingertip motion to
positional changes of the entire body
Bone Classification and Surface Markings
© 2015 Pearson Education, Inc.
, Six categories of bone based on shape
1. Flat bones
2. Sutural bones
3. Long bones
4. Irregular bones
5. Sesamoid bones
6. Short bones
1. Flat bones
Thin, roughly parallel surfaces
Examples: cranial bones, sternum, ribs, scapulae
Protect underlying soft tissues
Provide surface area for skeletal muscle attachment
2. Sutural bones (Wormian bones)
Irregular bones formed between cranial bones
Number, size, and shape vary
3. Long bones
Relatively long and slender
Examples: various bones of the limbs
Femur (long bone of the thigh) is the largest and heaviest bone
in the body
4. Irregular bones
Complex shapes with short, flat, notched, or ridged surfaces
Examples: vertebrae, bones of pelvis, facial bones
5. Short bones
Small and boxy
Examples: bones of the wrist (carpals) and ankles (tarsals)
Surface markings
o Also known as bone features
o Related to particular functions
Elevations/projections
o Tendon and ligament attachment
o At joints where adjacent bones articulate
Depressions/grooves/tunnels
o Sites for blood vessels or nerves to lie alongside or
penetrate bone
Surface markings – general
o Head
Expanded proximal end of a bone that forms part of a joint
o Diaphysis (shaft)
Elongated body of a long bone
o Neck
Narrow connection between the head and diaphysis of a bone
Surface markings – elevations or projections
© 2015 Pearson Education, Inc.
o .
The Skeletal System
Skeletal system components
o Bones (~206 total)
Divisions
1. Axial skeleton (126 bones)
Bones of skull, thorax, and vertebral column
Form longitudinal axis of body
2. Appendicular skeleton (80 bones)
Bones of the limbs and girdles that attach them to
the axial skeleton
o Associated cartilages
o Ligaments and other connective tissues
Functions of the skeletal system
o Support
Structural support for body
Framework for attachment of soft tissues and organs
o Storage of minerals and lipids
Concentrations of calcium and phosphate ions in the blood must
be maintained
o Calcium most abundant mineral in body
o Calcium salts in bone act as mineral reserve
Adipose tissue in bones stores lipids
o Blood cell production
Red bone marrow (filling internal cavities of many bones) is
production site for all formed elements of blood
o Protection
Skeleton protects delicate tissues and organs
o Ribs protect heart and lungs
o Skull protects brain
o Vertebrae protect spinal cord
o Pelvis protects digestive and reproductive organs
o Leverage
As levers, bones change magnitude and direction of skeletal
muscle forces
Produce movements ranging from delicate fingertip motion to
positional changes of the entire body
Bone Classification and Surface Markings
© 2015 Pearson Education, Inc.
, Six categories of bone based on shape
1. Flat bones
2. Sutural bones
3. Long bones
4. Irregular bones
5. Sesamoid bones
6. Short bones
1. Flat bones
Thin, roughly parallel surfaces
Examples: cranial bones, sternum, ribs, scapulae
Protect underlying soft tissues
Provide surface area for skeletal muscle attachment
2. Sutural bones (Wormian bones)
Irregular bones formed between cranial bones
Number, size, and shape vary
3. Long bones
Relatively long and slender
Examples: various bones of the limbs
Femur (long bone of the thigh) is the largest and heaviest bone
in the body
4. Irregular bones
Complex shapes with short, flat, notched, or ridged surfaces
Examples: vertebrae, bones of pelvis, facial bones
5. Short bones
Small and boxy
Examples: bones of the wrist (carpals) and ankles (tarsals)
Surface markings
o Also known as bone features
o Related to particular functions
Elevations/projections
o Tendon and ligament attachment
o At joints where adjacent bones articulate
Depressions/grooves/tunnels
o Sites for blood vessels or nerves to lie alongside or
penetrate bone
Surface markings – general
o Head
Expanded proximal end of a bone that forms part of a joint
o Diaphysis (shaft)
Elongated body of a long bone
o Neck
Narrow connection between the head and diaphysis of a bone
Surface markings – elevations or projections
© 2015 Pearson Education, Inc.
