NPTE : TMJ + Spine (joints , actions , ranges , etc)

Lower TMJ joint

type of joint

articulation between

Hinge Joint

- mandibular condyle

(covered in fibrocartilage + dense fibrous CT)

+

- inferior disc surface.

Upper TMJ Joint

type of joint

articulation between

Gliding Joint

- superior disc surface

+

- articular eminence

What is unique about the two joints of the TMJ compared to other synovial joints?

Articular Surfaces are covered in fibrocartilage

rather than hyaline cartilage

Weighbearing surface of the TMJ Intraarticular Disc

compare this potion of the disc to the rest of the disc

Intermediate : between condyle and temporal bone

- thinnest portion

- NOT innervated

How does the intra-articular disk of the TMJ move

moves WITH the condyle most of the time

intra-articular disc of the TMJ : attachments

Anterior

- bone

- joint capsule

- tendon of lateral pterygoid muscle (superior head)

Posterior = bilaminar retrodiscal tissue

Anterior Attachment of Disc of TMJ

tendon of lateral pterygoid muscle (superior head)

Posterior Attachments of Disc of TMJ

Posterior = bilaminar retrodiscal tissue

Bilaminar Retrodiscal Tissues of TMJ

location + function

superior vs. inferior

- attachments

- composition

posterior anchor to limit anterior translation of the disc

Superior Lamina = elastin rich

- attaches to the temporal bone

Inferior Lamina = collagen rich

- attaches to the neck of the mandibular condyle

Limits Anterior Translation of the Intraarticular disc of the TMJ

parts?

Bilaminar Retrodiscal Tissues

Superior Lamina = elastin rich

- attaches to the temporal bone

Inferior Lamina = collagen rich

- attaches to the neck of the mandibular condyle

TMJ Joint Capsule

attachments

is it vascularized / innervated?

compare its tightness A-P vs. M-L

- why is this important

superiorly

= temporal bone

inferiorly

= neck of mandibular condyle.

Highly vascularized + innervated

Loose (lax) A-P

- easier opening + closing

Tighter Med-Lat

= for lateral stability with chewing

OSTEOKINEMATICS: TMJ

movements available (5)

- distances of each in mm

mandibular movements

Depression (opening): 35-50 mm

-requires protrusion

Elevation (closing)

- requires retrusion

Protrusion (chin forward): <8 mm

Retrusion

(chin backward; aka: Retraction): <5 mm

Lateral Deviation

(lateral jaw excursion) 10-15mm

Protrusion vs. Retrusion

average motions

Paired with what other motions

Protrustion = <8 mm

= depression

Retrusion = <5 mm

= elevation

ARTHROKINEMATICs of TMJ : Depression vs. Elevation

2 main principals

where does each occur

when does each occur

describe each TMJ motion

1) Rotation = lower joint space

mandibular condyles rolls on inferior surface of disc

= first < 50% of opening

2) Translation = upper joint space

condyle AND disc slide together

= added to rotation during last 50+% for full opening.

TMJ elevation (closing) = reverse order.

TMJ protrusion and retrusion

= all translation of condyle-disc complex.

TMJ lateral deviation

= mostly translation of condyle-disc complex

+ some multiplane rotation (mostly horizontal plane)

TMJ Musculature : Depression

(opening)

bilatateral

lateral pterygoids (inferior head)

suprahyoids

(submandib ms)

TMJ Musculature : Protrusion

paired with what other motion

Paired with Depression

bilateral

primarily lateral pterygoids

+

- masseters

- medial pterygoids

TMJ Musculature : Retrusion

paired with what other motion

Paired with Elevation

bilateral

temporalis

+

suprahyoids

TMJ Musculature : Lateral Deviation

Contralateral Pterygoids

+

Ipsilateral

- temporalis

- masseter

Muscles attached to TMJ Disc

Superior head of lateral pterygoid

note : eccentric action during closing of mouth to manage disc position

TMJ Hypomobility (+ misalignment)

- what is hypomobile?

- what does it result in?

= anteriorly displaced disk (= stuck)

- limited ROM (blocked by the disk)

+

- pain (loading on improper area of the disk)

TMJ Hypermobility

(popping) disc

(typically anteriorly displaced)

NOT STUCK = moves too much

= pain and degeneration of disk.

Classic scenario:

- opening pop of the disk

and

- closing pop of the disk

as it snaps in and out of place on the condyle.

Anatomy of the Spine

how many vertebrae (including fused)

what are the regions (+ how many vertebrae in each)

how many spinal nerves

33 vertebrae (9 fused)

Cervical = 7

Thoracic = 12

Lumbar = 5

Sacral = 5 (fused)

Coccyx = 4 (fused)

How many IVDs

23

none between:

9 fused vertebrae

+

Occipital - C1

+

C1 - C2

how many spinal nerve

how are they named

31 pairs

C1-C7 = comes out above vertebrae

C8

T1-S5 = comes out below vertebrae

Major Ligaments of the Spine

what do they prevent

NARROW vs. BROAD

Anterior Longitudinal Ligament

C1 - sacrum;

= tightens w/ extension

= narrow (c-spine) -> Wide (L-spine)

Posterior Longitudinal Ligament

C2 - sacrum

= tightens w/ flexion

= Wide (c-spine) - Narrow (L-spine)

Ligamentum Flavum

C2 - sacrum = lamina to lamina

= tightens w/ flexion

Interspinous Ligament

– tightens w/ flexion; weaker

•Supraspinous Ligament

C7 - sacrum

(= Ligamentum Nuchae in C-spine)

– tightens w/ flexion; weaker

Only spinal ligament to prevent EXTENSION

where does it run from/to

describe its shape from c-spine --> L-spine

Anterior Longitudinal Ligament

C1 - sacrum

narrow (c-spine) --> wide (L-spine)

What determines the AMOUNT of movement between two vertebrae

vs.

The Direction of Movement (ie in what plane)

Amount of movement = Intervertebral Jt.

vs.

Direction of movement in each plane = Facet Jts

Typical Spinal Segment :

- how many joints

- name the joints + what type are they

2 vertebrae

2 facet joints (synovial)

1 intervertebral (cartilaginous)

3 total

When a spinal segment is in extension

- where is the tension (stretch) in the anulous fibrosis (AF) and which direction is the nucleus pulposous (NP) pushed (due to compression)

What about when a segment is in Flexion?

AF = tension is Anterior

NP = pushed Anterior

flexion = opposite

What determines the AMOUNT of movement between two vertebrae

Intervertebral Jt.

The PROPORTION of movement in a given plane

Facet Jts

Spinal Segment

= made of up _________

Arthrokinematics of Spinal Segment Motion

= 2 vertebrae, disk, & facet joints

“Top moving on Bottom” motion

Facets glide/slide

(arthrokinematics)

Flexion

anterior-superior slide (top moving)

= open pack position.

Extension

posterior-inferior slide (top moving)

= closed pack position

Rotation & Sidebending

= also top-on-bottom

Coupling of Motion

Which motions are coupled together

Type I vs. Type II

Rotation and Lateral Flexion (Sidebending)

at most but not all regions of the spine.

All assume NEUTRAL starting position

Type I Motion Coupling Pattern:

- Rotation + sidebending

occur together

BUT

opposite directions

Where do this occur

- O/A

(not A/A - does rotation only)

- mid & lower T-spine

- all of L spine.

Type II Motion Coupling Pattern: Rotation and sidebending

together + in same direction

Where does this occur

- lower C-spine

- upper T-spine

Type I Motion Coupling

what motions

same or opposite directions

where does it occur

Rotation + sidebending

occur together

BUT

opposite directions

Where :

- O/A

(not A/A - does rotation only)

- mid & lower T-spine

- all of L spine.

Type II Motion Coupling

what is it

where does it occur

Type II Motion Coupling Pattern: Rotation and sidebending

together + in same direction

Where does this occur

- lower C-spine

- upper T-spine

Sub regions of the Cervical Spine (2)

define (inc how many segments in each)

Suboccipital (upper C-spine)

= occipital bone, C1, & C2

(2 spinal segments)

Lower Cervical Spine

bottom of C2 - Top of T1

(6 spinal segments)

Suboccipital Joint Motions : upper joint

name the joint

articulating surfaces

arthrokinematics

motions (inc ranges)

why is it unique

Occipito-Atlantal Joint (OA):

2 x occipital condyles (convex)

+

2 x articular surfaces of atlas (CC)

NO DISK

Motion

- Flexion/Extension ~15°of each (nodding of head)

+ small amounts of

- Lateral Flexion & Rotation

(Type I motion)

Suboccipital Region : lower joint

name the joint(s)

articulating surfaces (3)

arthrokinematics

motions (inc ranges)

why is it unique

Atlanto-Axial Joint (AA)

3 synovial joints

– 1 pivot joint

- 2 facet joints

NO DISK.

Motion:

Rotation = 35-40°

but NOT coupled

+

Flexion/Extension is minimal (10-15°)

+

Lateral Flexion is even less

rotation atlas (C1)

on

stationary axis (C2)

Ex: Left rotation = atlas turns CC on axis.

IMPORTANT: Approximately 50% of the total rotation of the entire cervical region occurs at the AA before rotation occurs in the rest of the cervical region.

Which joint has the max rotation of c-spine

What is the ROM

Atlanto-axial (AA) Joint

35-40°

Describe the Progression of C-spine Rotation

Approx 50% of the total rotation occurs at the AA

BEFORE

any rotation occurs in the rest of the cervical region.

Lower Cervical Spine Motions (ROM) : Flexion / Extension

at what segments does the most movement occur?

C2-T1

max motion occurs at C4-5 & C5-6.

= these 2 segments are often the first to show signs of disk and joint degeneration.

Lower Cervical Spine Motions (ROM) : Flexion/ Extension

describe the motions

at what segments does the most movement occur?

C2-T1

F = 45-60

E = 50 -65

max motion occurs at C4-5 & C5-6.

= these 2 segments are often the first to show signs of disk and joint degeneration.

C-Spine Segments that are often first to show disc + joint degeneration

Why?

C4-5 & C5-6.

because this is where max flexion + extension of c-spine occurs

ex. Lower c-spine rotation to the right

- describe in terms of facet joints

right facet = closes

left facet = opens

Summary : Type I vs. Type II motion in the C-spine

- name the 3 segments and their respective motions

OA = Type I

AA - neither (rotation only)

C2-3 thru C7-T1 = Type II

Overall AROM at C-spine:

- what motions

- ranges

Flexion 45-60°

Extension 50-65°

Lateral Flex 40-45°

Rotation 70-80° each

(35-40 from AA prior to rest occuring)

ROM C-Spine Flexion

primarily occurs at what levels

45-60°

max motion occurs at C4-5 & C5-6.

ROM C-Spine Extension

primarily occurs at what levels

50-65°

max motion occurs at C4-5 & C5-6.

ROM C-Spine Lateral Flexion

primarily occurs at what levels

also coupled with what motion + type of coupling

40-45°

occurs at all levels C2-T4/5

Type II couple (same direction)

with rotation

ROM C-Spine Rotation

where does this occur at what levels

also coupled with what motion + type of coupling

70-80° TOTAL (each direction)

35-40 from AA BEFORE rest = Type I coupling (opposite directions)

35-40 from lower c-spine = Type 2 coupling (same directions)

Facet Joint Orientation at OA

- describe their orientation and how this impacts movement

O = convex

on

A = concave

CVX on CC = roll = opposite to slide

Facet Joint Orientation at AA

- describe their orientation and how this impacts movement

20° from transverse plane = ROTATION

Facet Joint orientation : lower c-spine

what segments

describe orientation

what motion does this favor?

C2 on C3 - C7 on T1 (6 segments)

= 45° from transverse (and frontal)

... transitions to ~30° at lower end (towards frontal)

= favors rotation + lateral flexion

T- Spine : Unique Synovial Articulations (2)

what are they

classification of joints

are they mobile , well innervated?

Costovertebral Joints

Costotransverse joints

plane, synovial joints

mobile and well innervated

Motions of Thoracic Spine : Flexion / Extension

compare upper vs. lower

Possible throughout thoracic spine

extremely limited in upper T-Spine

= ROM increases caudally

More Flexion available overall

Motions available at T-spine

what are they

describe each in terms of rostral --> caudal

flex/ext = INCREASES caudally

very limited in upper t-spine

lateral flexion = INCREASES caudally

limited due to rib cage

rotation = DECREASES caudally

limited due to ribs + facet orientation

Facet Joint Orientation in the T-spine

- break it down by region

- how does this impact motion

T 1 - T 10 = Frontal Plane

vs.

T 10 - 12 = quick transition to Sagittal

= favors flexion & extension

Scoliousis Class Example

Upper thoracic vs. Lower thoracic / Upper Lumbar

- which side is the lateral flexion

- what happens to the ribs on each side

- which direction is the rotation

Upper Thoracic = L Lateral Flexion

ribs on R side

- elevated

- IC spaces more open

ribs on L side

- depressed

- IC compressed / shrink

Rotation to the Right

Posterior Rib Hump = RIGHT

(vs. rib flattening on Left)

VS.

Lower Thoracic / Upper Lumbar

= R Lateral Flexion

LEFT ROTATION

Posterior Rib Hump on LEFT

Scoliosis : Changes in Rib Position

Posterior Rib Hump

- Same side as rotation and thus opposite to side of lateral flexion

(be represents lower T-spine = type I coupling)

thus anterior hump = same side as lateral flexion

Contralateral to Lateral Flexion

- Ribs elevate

- Thoracic cage enlarged

- Intercostal spaces widen

vs.

Ipsilateral to Lateral Flexion

- Ribs depress

- Thoracic cage shrinks

- Intercostal spaces narrow

Any Spinal Curvature in the Frontal Plane =

Scoliosis

Lumbar Region : Facet joint Orientation

- overall orientation

- superior vs. inferior vertebrae for a given section

differentiate between 2 regions

L1-4 = Sagittal Plane (close to)

at each segment

- upper facet = faces laterally

vs.

- lower face = faces medially

L5-S1 = near the Frontal Plane

- facet surface of L5 faces anterior

- facet surface of S1 faces posterior

= resists anterior movement of L5 on S1 due to normally occurring anterior shear forces

(Just like T-Spine)

Motions : Lumbar Spine

primary motion(s)

coupling??

explain what happens to facet joints on each side

Primarily : Flexion & Extension

(due to facet orientation)

+

Lateral flexion + rotation

= limited due to orientation of facets.

Type I Coupling

( Lateral Flexion and Rotation )

= OPPOSITE DIRECTION

Ex.

R. lateral flexion = L. rotation (some)

Lateral flexion (pictured)

= Closing of ipsilateral facet

+ opening of contralateral facet

vs.

Rotation (pictured)

= opening of ipsilateral facet

+ closing of contralateral facet

Therefore, a person with a hypomobile lumbar facet joint on the RIGHT will be limited in right rotation and left lateral flexion (at that vertebral segment)

Q: How does this effect the entire lumbar spine?

A person with a hypomobile lumbar facet joint on the RIGHT will be limited in _____________

Explain

limited in:

- right rotation

+

- left lateral flexion

(at that vertebral segment)

bc TYPE I Coupled

Spondylolisthesis

what is it

what structures support / protect against this?

Slippage of L5 on S1

- damage spinal nerves / cauda equina

limited by

facet orientation (frontal plane)

- L5 = anterior

vs.

- S1 = posterior

= BLOCKS L5 from slipping anteriorly

Intradiscal pressures in Lumbar Region

what is the baseline

describe trends

= what causes you to go above or below baseline

compression due to body weight & m contraction

standing = 100%

leaning forward = increases forces

supine = lowest

side

design programs to prevent lumbar disk NP herniation or limit any additional damage.

In order for the nucleus pulposus to escape the annulus fibrosis, the annulus must be weakened or torn.

Are SI joints strong/stable

why or why not

VERY STABLE

Extremely strong ligaments reinforce the joint on all sides.

Motion of Sacrum on Ilium:

how does this affect pelvic inlet/outlet

changes during pregnancy?

Primary motion of SI

Flexion (nutation) (nod)

– anterior tip of sacrum moves anteriorly + inferiorly

- coccyx moves posteriorly

vs.

Extension (counternutation)

– anterior tip of sacrum moves posteriorly + superiorly

- coccyx moves anteriorly.

How do Nutation & Counternutation affect size of the Pelvic Inlet & Pelvic Outlet ??

pregnancy

- softening of ligaments

= increased joint mobility + decreased stability of SI joints

= likelihood of joint dysfunction and pain.

Nutation

what is it

2 possible ways for it to occur

SI "Flexion"

1. SI moving on stable Pelvis

2. Posterior Pelvic tilt

(stable sacrum)

Counternutation

SI "Extension"

1. SI moving on stable Pelvis

2. Posterior Pelvic tilt

(stable sacrum)

Muscles of the Spine/Trunk: Function to stabilize trunk & pelvis (control postures) and move the trunk/spine.

(TABLE)

External Oblique = SCM for Action

(ie Ipsi flexion + sidebend but opposite rotation)

Intervertebral Foramen Space Issues:

describe structures in relation to IV foramen / spinal nerve

how does flexion / extension affect space

affect of disc height?

anterior = disk

posterior = facet joint

posteromedial

= ligamentum flavum

degeneration or dehydration of disc = narrows IV space

flexion = increases size

extension = decreases size

Protraction of the Head (Forward Head)

compare position of upper c-spine vs. mid to lower c-spine

what is the overall outcome of this?

upper C-spine = extension

vs.

Mid & Lower C-spine = flexion

increases stress on :

- levator scapulae

- semispinalis capitis

+

shortens SCMs