Spine

moment arm

perpendicular distance from muscle insertion to joint axis

muscle torque

a force applied through a moment arm to produce (or prevent) rotation around a joint

large moment arm

greater force production but less ROM, less joint compression/stability (brachioradialis/iliopsoas)

small moment arm

less force production but more ROM, more joint compression/stability (multifidus/erector spinae)

larger

global muscles have a _____ IMA and therefore greater force production

smaller

local muscles have a ____ IMA and therefore more stability

muscle torque potential

force generated in parallel plane + length of moment arm = ___ ____ ____

superficial global group

moment arm for spine extension or side-bend

- 3 groups

- cross many vertebrae/joints

- common tendon on sacrum

- assist in anterior pelvic tilt

- poor stability/compression ability (advantage for motion)

extension

if someone has overactive erector spinae they have more ____

- SI joint not in CPP= more room for error

intermediate and deep local group

- span less vertebrae, joints

- shorter, more stout

- shorter lever arm

- better stabilizer/compressor than mover

- multifidi thickest in lumbar region

- poor rotation and extension ability

anterior spine muscles

support/protect viscera

increase intra-abdominal and intrathoracic pressure

all share fascial connections

- RA, OEA, OIA, TA

rectus abdominis

sagittal plane

flexes trunk

long lever arm

external obliques

sagittal plane; flexes trunk

rotates trunk in horizontal plane

internal obliques

sagittal plane; flexes trunk

rotates trunk in horizontal plane

TA

horizontal plane

compresses trunk

RA, EO, IO, TA

what is the order from most superficial to deep of the anterior spine muscles?

RA, EO, IO, TA

what is the order from primarily mover and primarily stabilizer of the anterior spine muscles?

flex

muscles anterior to ML axis _____ the spine

extend

muscles posterior to ML axis _____ the spine

laterally

muscles R/L to the AP axis _____ flex the trunk

psoas major

line of force passes through or near ML axis

- short moment arm (compression/stability)

- flexor moment at lower lumbar segments

- extensor moment at upper lumbar flexors

QL

lumbar extensor

- strong vertical stabilizer/compressor

- also side-bends spine unilaterally

extrinsic

____ trunk muscle stabilizers

- aka superficial trunk muscles, global trunk muscles, and prime trunk movers

- abdominals, erector spinae, QL, psoas, hip muscles

- large multi-joint/region muscles

- provide limited core stability (splinting)

- imbalance can lead to potential deformities and spinal degeneration

- overlap and redundant with intrinsic muscles

intrinsic

_____ trunk muscle stabilizers

- aka deep core muscles, local core muscles, and local prime stabilizers

- multifidi, rotatores, semispinalis, interspinalis

- short, stout muscles, cross minimal segments

- high percentage of slow twitch fibers

- high # muscle spindles (sense/fine tune spine position)

- lessen shear forces to spinal structures

- vertical orientation parallel to spine (besides TA)

- first to activate with anticipated extremity movements

- susceptible to inhibition/asymmetry

global

____ group of cranio-cervical stabilizers

- SCM, scalenes, LS, and splenius capitis

local

____ group of cranio-cervical stabilizers

- longus colli, longus capitus, rectus capitus, and suboccipitals

- susceptible to inhibition and asymmetry

longus colli

with forward head posture the _____ _____ is in passive insufficiency

40 degrees

what is the expected/normal degree of spinal curves?

muscle

the spine may be hypo or hypermobile depending on activities performed or _____ activity

stretches; mobilizations

clinicians try to optimize spinal curves via _____, exercises, and joint _____

spinal column regions

all support body weight

all protect the SC and nerves

serve as attachment points for passive, stabilizing structures

serve as attachment points for stabilizing and movement muscles

purpose of cervical spine

ideal to resist gravity/compression (vertical)

purpose of thoracic spine

stability primarily and limited movement

purpose of lumbar spine

stability and most load bearing

C7 and T1

the CT junction is between what two vertebrae?

T12 and L1

the TL junction is between what two vertebrae?

L5 and S1

the LS junction is between what two vertebrae?

structural

junction sites share ______ similarities of both regions and therefore are notorious for dysfunction

instigate

junction sites may ____ pathomechanics above and below the spinal level

skeletal

repetitive movements and sustained postures contribute to _____ syndromes

CT and TL

the spinal canal narrows at what 2 junctions?

true

T/F: vertebral disorders commonly involve neural impairments

spinal

pathomechanics and failing spinal structures produce ____ syndromes such as low back pain

common

neuromuscular and muscular dysfunction is _____ in spinal injuries/pathomechanics

concave

cervical and lumbar curves are _____ posteriorly (lordosis)

convex

thoracic and sacral curves are _____ posteriorly (kyphosis)

increases; decreases

spine extension ____ lordosis and _____ kyphosis

increases; decreases

spine flexion ____ kyphosis and _____ lordosis

dynamic

spinal curves are ____ in that they bend but don't break

mastoid; S2; hip

in ideal posture the LOG passes:

- through _____

- anterior to: ____, knee, and ankle

- posterior to: _____ joint

spinal

the LOG straddles _____ curves and major joints

flexion

the LOG produces ____ torque if anterior to COG

- little old lady/man with a walker

extension

the LOG produces _____ torque if posterior to COG

- santa/beer belly (increased lordosis of lumbar spine)

systemic

postural deviations may occur from ____ illnesses or small deviations over long periods of time (repeated microtrauma)

mobile

cervical vertebrae have the smallest body, are the most ____, and have a small disc

occiput/C1

mainly flexion and extension

convex on concave

C1/C2

mainly rotation

C7/T1

transition/dysfunction zone

contributes to cervical motion but provides stability at the same time

C3-C6

uncovertebral joints are which vertebrae?

45 degrees

cervical spine facets are oriented at what degree from the horizontal?

60 degrees

thoracic spine facets are oriented at what degree from the horizontal?

rotation

thoracic spine restricts ____ but enhances/allows lateral flexion, and flex/ext

organs

ribs limit motion but protect _____

short; thick

lumbar vertebrae have laminae and pedicles that are ____ and ____

vertical

lumbar facets are oriented nearly ____ in the sagittal plane

- resists rotation and side bending

frontal

L5/S1 orients towards the ____ plane to allow for more rotation/flex/ext

SI

since L5 and S1 are atypical and allow more motion to occur this also allows motion to be transmitted coming from the ____ joint

shear

neutral spine decreases ____ and torsion when all joints are in line

increases

transverse and SPs ____ the mechanical advantage of ligaments and muscles

limit

apophyseal joints guide or ____ motion of the spine

interbody joints

vertebral endplate

connects disc to vertebral vertebrae

distributes and absorbs vertical loads

disc is the "spacer" of the spine

small

at any given vertebral level, the motion of joint play is ____ however when working together at multiple levels this can yield a lot of rotational motion

several

restricted motion in the spine is dictated by ____ spinal segments and treatment should reflect this

facet joints

apophyseal joints

essentially planar

concave/convex rule still apply

either open/close or gap facet

local muscles

_____ _____ of the spine

- short, stout, almost parallel to vertical axis of spine

- rotatores, multifidus

global muscles

____ _____ of the spine

- long, multiple attachments farther away from vertical axis

- longissimus, semispinalis

TA

concentric activation in horizontal plance

linea alba to TFL

stabilizes spine via intra-abdominal pressure (natural corset)

intervertebral discs

hydraulic shock absorption

dissipates force and transfers forces through adjacent vertebral bodies

resists vertical separation, shear forces, and torsion

opposite

the concentric layers of annulus run _____ directions to provide stability

- 65 degree geometric compromise accomplishes this

facet

a hydrated disc protects vertebral bodies and ____ joints

degeneration

dehydrated disc is a precursor to ____ of facet and vertebral endplate

- less resistant to forces

neutral spine

what is the ideal position to distribute forces?

increases

disc pressure _____ when:

- lifting a load and load is held away from body

- lifting a load with knees flexed is less pressure than knees extended

- slouched sitting > erect sitting

spine coupling

spinal movement in one plane causes movement in a second plane

counter curve locking

a lot of manual therapists and chiros use this method to correct joint dysfunction

coupling

asymmetry in movement may identify a joint ____ error

AO joint

occiput on C1

convex occiput on concave C1 facets

mainly flex/ext of the head (10-20 degrees)

no rotation but possibly some lateral flexion

posteriorly

to correct forward head posture you glide _____

flexion

a very common dysfunction at C0 and C1 is a restriction in _____ motion

down; back

with cervical extension the facets move ____ and _____

up; forward

with cervical flexion the facets move ____ and ____

full extension

what is CPP of spine

lower

during cervical flexion counter-curve lock occurs at the _____ cervical levels to mobilize the upper cervical levels

AA joint

C1 and C2 articulation

pivot joint

2 joints: medial and lateral

dens on arch of C1

50%

what percent of cervical rotation occurs at the AA joint?

AA

the ____ joint is common site of joint dysfunction

- hanging spine level

T6

rotation occurs through ____ spinal levels

transverse

the AA joint is supported by _____ and alar ligaments

40

about ____ degrees of rotation occurs at C1/C2 and the remainder is provided through down to T6 (80 degrees total)

down; back; up; forward

with right rotation the right facets move ____ and ____ while the left facets move ____ and _____