Spine biomechanics

Question 1

Which are the primary and secondary curves of the spine?

Answer 1

Primary curves are kyphotic (from fetal flexion) - thoracic and sacral

Secondary curves are lordotic (from muscle engagement in crawling and standing upright) - cervical and lumbar

Question 2

Describe the 4 curves of the spine

Answer 2

Cervical lordosis - 30
Thoracic kyphosis - 40
Lumbar lordosis - 45
Sacral kyphosis - 30

Question 3

Which movements are available at the spine, and what are the associated arthrokinematics?

Answer 3

(movements are always a slide, and always initiated by the upper vertebrae, and occur between the inferior facets of the upper vertebrae and the superior facets of the inferior vertebrae)

Flexion:
slide: anterior and superior

Extension
slide: posterior and inferior

Lateral flexion:

ipsilateral: slide inferiorly & posteriorly
contralateral: slide superiorly & anteriorly

Rotation:

ipsilalteral: slide inferiorly posteriorly
contralateral: slide superioroly & anteriorly

Question 4

What are the ranges of motion available at each segment of the spine?

Answer 4

Flexion:
Cx: 45
Tx: 30-40
Lx: 50

Extension:
Cx: 90
Tx: 20
Lx: 15

Lateral flexion:
Cx: 80
Tx: 50
Lx: 40

Rotation:
Cx: 180
Tx: 60
Lx: 10