bone and joint biomechanics

Question 1

functions of the skeleton

Answer 1

-support body weight
-movement
-protect critical structures
-store materials such as calcium
-blood cell production

Question 2

major constituents of bone

Answer 2

-calcium carbonate + calcium phosphate (mineral)
-Collagen (organic)
-Water (25-30%)

Question 3

Mineral part of bone

Answer 3

stiffness: ration of stress to strain
compressive strength: ability to resist pressing or squeezing forces

Question 4

organic part of bone

Answer 4

tensile strength: ability to resist a stretching force

Question 5

Classification of Bone Tissue

Answer 5

Cortical (compact)
Trabecular (cancellous)

Question 6

Cortical

Answer 6

dense layer that makes up outer layer of bone
-particularly in long bones
-can withstand more stress but less strain

Question 7

Trapecular

Answer 7

spongy bone with a honeycomb-like structure
-allows for a high strength to weight ratio
-shock absorbance
-looks like honeycomb
-can withstand more strain but less stress

Question 8

stress

Answer 8

the amount of force or loading on a tissue/area

Question 9

strain

Answer 9

the amount of deformation divided by the original length of the structure

Question 10

Skeleton

Answer 10

177 are involved in movement; 206 in total
-axial: skull, spinal, column, sternum and ribs
-appendicular: upper and lower extremities, inclusion the pelvis and the scapula

Question 11

types of bones

Answer 11

Long, short, flat, and irregular

Question 12

Long bones

Answer 12

shaft or body with a medullary canal, and relatively broad, knobby ends
-have a diaphysis or cortical bone and epiphyses of trabecular bones
-FUNCTION: lever arms for movement

Question 13

Long Bones Examples

Answer 13

arms: clavicle, humerus, radius, ulna, metacarpals, phalanges
legs: femur, tibia, fibula, metatarsals, phalanges,

Question 14

short bones

Answer 14

relatively small, chunky, cube-like
-Filled with trabecular bone
-FUNCTION: shock absorption

Question 15

short bone examples

Answer 15

carpals, tarsals, including the calcaneus

Question 16

flat bones

Answer 16

flat and plate like
-FUNCTIONS: protection of internal organs and provide a broad surface for a muscle attachment

Question 17

flat bone examples

Answer 17

superior, posterior portion of the skull, sternum, ribs, ilium, and scapula

Question 18

Irregular bones

Answer 18

FUNCTION: unique structure for a unique function

Question 19

irregular bone examples

Answer 19

facial bones, maxilla, mandible, vertebrae, sacrum, coccyx, patella
-sesamoid: bone embedded in a tendon

Question 20

Trabecular alignment

Answer 20

trabeculae develop based on the stresses placed on a bone with respect to it’s axis

Question 21

anisotropic

Answer 21

exhibits different mechanical properties in response to loads from different directions
-bone is strongest in resisting compression and weakest in resisting shear forces

Question 22

types of bone cells

Answer 22

osteoblasts, osteoclasts, osteocytes
-maintain bone density

Question 23

osteoblasts

Answer 23

“Bone Builders”
responsible for bone deposition
-recepters
-mechanorecepters and estrogen
-in the periosteum
-add bone to the external part of diaphysis

Question 24

Osteoclasts

Answer 24

“bone crumblers”
responsible for bone resorption
-work steady throughout lifetime
-in the endosteum
-remove bone from the internal surface
-use HCL to dissolve bone mineral
-use enzyme to digest collagen

Question 25

osteocyte

Answer 25

bone cell
-monitors health of bone matrix

Question 26

bone remodeling

Answer 26

process of removing old bone tissue and depositing new bone tissue
-completly remodels every 2 years
-more force makes it go faster
-older you are gets slower

Question 27

Epiphyseal plates (long bones)

Answer 27

cartilage between epiphysis and main part of bone where growth can occur
-2 in each long bone

Question 28

when growth comes to an end

Answer 28

-chondroblasts divide less often and plate becomes thinner
-last long bone to grow is the clavicle

Question 29

appositional growth

Answer 29

growth of a bone by addition of bone tissue to its surface
-all bones undergo this growth

Question 30

wolff’s law

Answer 30

bone strength increases and decreases as the functional forces on the bone increase and decrease
-bone hypertrophy: increase
Bone atrophy: decrease

Question 31

order osteoclasts work

Answer 31

resorption, reversal, formation, resting