Spine Kinesiology

what are the 5 functions of the spine

1. shock absorption

2. rigid column

3. attachment for muscles and ligaments

4. protect the spinal cord

5. supports the thorax

How many of each type of spinal vertebrae are there?

7 cervical

12 thoracic

5 lumbar

5 sacral (fused)

4 coccygeal (fused)

name the spinal curves and where they occur

cervical lordosis

thoracic kyphosis

lumbar lordosis

sacrococcygeal kyphosis

describe lordosis

an inward curve

convexity is anterior

in the cervical and lumbar regions

describe kyphosis

an outward curve

convexity is posterior

in the thoracic spine

describe scoliosis

sideways curve of the spine

Normal curves develop as upright posture is assumed. When do the cervical and lumbar spinal curves develop?

cervical: by age 3 months

lumbar: complete by age 10

are spinal curves static?

no, a change in one curve is compensated by a change in another curve

a neutral angle of pelvic tilth means

the ASIS and pubic tubercle are vertically aligned

an anterior pelvic tilt means

the ASIS is anterior to the pubic tubercle

more lordosis in lumbar spine

a posterior pelvic tilt means

the ASIS is posterior to the pubic tubercle

less lordosis in the lumbar spine

what effect does an anterior pelvic tilt have on the lumbar spine curvature?

an increase in lordosis

what effect does a posterior pelvic tilt have on the lumbar spine curvature?

a decrease in lordosis

with an anterior pelvic tilt, what is happening with the intervertebral lumbar?

extension

with a posterior pelvic tilt, what is happening with the intervertebral lumbar?

flexion

vertebral body/disc weight bearing

bear 80%

most important in lumbar spine

want to evenly distribute load on disc

facet joints weight bearing

bear 20%

relative load on facet vs disc depends on spinal curvature and habitual motions

what are the 2 areas of vertebrae that weight bear

the vertebral body/disc and facet joints

In a gymnast who has extreme extension in her lumbar spine, is the load distribution increased on the facet joint or the vertebral body?

increased load in the facet joints

more pain, facet joint problem

increased lumbar lordosis

In a person who is bending down with extreme flexion in her spine, is the load distribution increased on the facet joint or the vertebral body?

increased load in the vertebral body

more pain, vertebral body/disc problem

decreased lumbar lordosis

typical vertebrae are made up of a vertebral body and a vertebral arch. What are the anatomical features of the vertebral arch?

transverse processes (2)

spinous process

pedicles (2)- connect arch to vertebral body

lamina (2) - spinous process to transverse process

articulating facets (4)

-2 superior and 2 inferior

what are the two other names for facet joints

zygapophyseal or apophyseal

describe the prominences of the spinous processes in the C-spine

C2 is the first prominent spinous process, then C6 and C7

typically bifid in C-spin

what effect do the T-spine spinous process have

shingle effect

what are the properties of the L-spine spinous processes

thick, flat SP

spinal flexion increases or decreases the distance between the spinous processes

increases

spinal extension increases or decreases the distance between the spinous processes

decreases

what anatomical feature on the vertebrae serves as “outriggers” for attachments of muscles

transverse processes

what cervical spine is the only one that has prominent transverse processes

C1

transverse foramen for vertebral artery

T1-T12 all have prominent transverse processes. What do they articulate with?

the ribs

what level are the mid-thoracic transverse processes at?

the SP level of the superior segment

how prominent are the transverse processes of L1-L5

very prominent

1” from SP

where is the primary weight bearing site for the spine

vertebral bodies

do vertebral bodies have increased or decreased thickness from C spine to L spine?

increased

Where are the C3-C7 uncinate processes?

on superior aspect of vertebral body

a spinal segment consists of

2 adjacent spinal vertebrae and the articulations that join them together

Ex: L4-L5, T5-T6, C6-C7

in a spinal segment, does the top or bottom move during spine motion

the top segment moves on the bottom

segments between 2 regions of the spine are called

transitional segmentswhat

list the transitional segments

C7-T1, T12-L1, L5-S1

what is the intervertebral foramen

the space in between pedicles

with what 2 motions does the intervertebral foramen open/increase in size

flexion and contralateral side bending

with what 2 motions does the intervertebral foramen close/decrease in size

extension and ipsilateral side bending

mixed nerve root has both

sensor and motor fibers

a mixed nerve root exits and the intervertebral foramen

the dorsal nerve root is afferent and carries

sensory information

the ventral nerve root is efferent and carries

motor information

what are the 3 categories of spinal joints

1. intervertebral disc

2. facet joints

3. special/atypical joints

an intervertebral disc

one between each 2 adjacent vertebrae, C2-S1

Facet joints

2 between each 2 adjacent vertebrae (R and L)

Special/atypical joints

1. occiput-C1: (atlantooccipital or AO joint)

2. C1-C2 (atlantoaxial or AA joint)

3. Uncovertebral: typically C3-C7

4. Rib articulations

5. pelvis: sacrum articulates with the ilium bone (SI joint)

what are the traits of facet joints

synovial joint

planar joint surfaces that slide rather than roll

guide intervertebral motion based on orientation direction

C2-S1 facet joints

facets are planar joints that glide rather than roll/slide. primary direction of glide depends on facet joint orientation

facet joint orientation of C2-C7

45 degrees from post-inf to ant-sup

facet joint orientation of T spine

Frontal plane, provides 1 degree of side bending

facet joint orientation of L spine

sagittal plane, provides 1 degree of flex/ext

The upper cervical spine is unique in facet joint orientation. what is the orientation of C0-C1 and C1-C2?

C0-C1: occiput is convex, C1 concave

C1-C2: horizontal, thus rotation most prominent motion here!

increased disc thickness from cervical to lumbar spine allows for more of what?

motion per segment

where do nerve roots exit

adjacent to disc via intervertebral foramen

where do C-Spine nerve roots exit

above vertebrae

where do L-spine roots exit

below vertebrae

how many cervical nerve roots are there?

8

C8 nerve root exits below C7 vertebra

how much water is in the intervertebral discs in the lumbar spine?

80%

less water % in C spine discs

why is disc herniation more common in the L-spine

there is more water in the L-spine

the C spine is more fibrous so less disc herniation

intervertebral discs make up what percent of spine length

25%

why do we get shorter as we age or during the course of the day

discs dry out and lose fluid

rehydrate with lying down

smaller height changes when younger, overtime lose overall height

what are the 5 functions of intervertebral discs

1. absorb shock

2. disperse stress

3. bind vertebra together

4. contribute to the spinal curves

5. allow movement (along with facet jt)

pascals law

pressure applied to a liquid is dispersed equally in all directions

what is the result of pascals law in the spine

vertical load is distributed outward against disc annulus

what are the 5 spine ligaments

1. anterior longitudinal ligament (ALL)

2. posterior longitudinal ligament (PLL)

3. ligamentum flavum

4. supraspinous and interspinous ligament

what are the characteristics of the ALL

runs along anterior vertebral body from C2-sacrum

limits extension

thicker and stronger than PLL (2X), thus minimizes anterior disc herniation

narrow in C spine and wider in L spine

what are the characteristics of PLL

runs along post. vertebral bodies from C2-sacrum

limits flexion in the spine

thick/wide in C spine = less posterior disc herniations in C spine

narrow in L spine = allows more posterior disc herniations in L spine

what are the characteristics of the ligamentum flavum

connect lamina to lamina from C2-sacrum

limit flexion

what are the characteristics of supraspinous and interspinous ligaments

run between spinous processes

limit flexion

ligament positions relative to the spinal cord

what type of tissue is thoracolumbar fascia made of

non-contractile, connective tissue

what role does the thoracolumbar fascia have

stabilizing lumbar spine (and SI joint) due to connections to spine, erector spinae, QL, gluteus max, latissimus, and abdominals