Biomechanics

Question 1

mechanical functions of vertebral body

Answer 1

protects spinal cord
enables movement
load bearing

Question 2

metabolic functions of vertebral body

Answer 2

haematopoiesis
mineral storage

Question 3

describe the basic structure of the vertebral body

Answer 3

core of trabecular meshwork
outer layer of cortical bone

Question 4

describe the ossification of the two types of bone

Answer 4

cortical - intramembranous
trabecular - endochondral

Question 5

describe the composition of cortical bone

Answer 5

structual units - osteons
central canals with surrounding lamellae
osteocytes
canaliculi
Volkmann’s canals

Question 6

describe the composition of trabecular bone

Answer 6

trabeculae network of rods and plates
cavities w/ bone marrow
honeycomb-like structure

Question 7

compare the functions of cortical and trabecular bone

Answer 7

cortical - strength, tensile resistance, protection and weight bearing

trabecular - haematopoiesis, flexibility, ion exchange, shock absorption

Question 8

compare trabecular orientations

Answer 8

vertical - 50%, bears compressive weight

horizontal - stabilise and link -> increased resilience

oblique - resists multidirectional forces -> increased resilience

Question 9

describe Wollf’s law for bone remodelling

Answer 9

bone remodels and adapts due to external forces applied to it - improved mechanical efficiency

Question 10

describe trabecular properties in cervical vertebrae

Answer 10

light and porous

Question 11

describe trabecular properties in thoracic vertebrae

Answer 11

more dense and compressed

Question 12

describe trabecular properties in lumbar vertebrae

Answer 12

strongest and highly dense

Question 13

describe trabecular properties in sacral vertebrae

Answer 13

thick and closely packed

Question 14

describe trabecular properties in coccygeal vertebrae

Answer 14

minimal

Question 15

describe the roles of cortical thickness

Answer 15

protection
weight distribution
strength
storage

Question 16

describe factors affecting cortical thickness

Answer 16

age
diet, exercise, alcohol, smoking
hormones
osteoporosis

Question 17

what are the main methods of measuring cortical thickness

Answer 17

CT and DEXA

Question 18

define the bony and cartilaginous end plates

Answer 18

bony - cranial and caudal regions of vertebral body

cartilaginous - structure of the IVD

Question 19

describe the structure of the bony end plate

Answer 19

thickened layer of cortex
porous
adjacent to trabecular bone

Question 20

describe the structure of the cartilaginous end plate

Answer 20

2 hyaline layers covering sup and inf of NP

Question 21

describe the function of the CEP

Answer 21

prevents disc bulging
attachment for NP and AF
stops fluid loss
even force dispersion

Question 22

overview Schmorl’s nodes

Answer 22

herniation of NP through end-plates
lower back pain
most in T spine
38-79% IR and more in males from (Kyere et al, 2012)