4 Thoracic Biomechanics Flashcards
What are the standard ranges for thoracic flexion, extension, rotation, and lateral flexion?
- Flexion 30-40
- Ext 20-25
- rotation 30-35
- Lateral flexion 25-30
Explain the movement of thoracic flexion
- Forward bending and exhalation
- anterior rotation and translation of superior vertebra on inferior vertebra
- inferior facet slide up and forward on superior facets
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- inferior facet slide up and forward on superior facets
Describe couple rib motin of thoracic flexion
- Superior vertebral body motion causes anterior rotation of rib head (inferior demifacet attachment)
- Anterior portion of ribs moves inferiorly
Superior vertebral body moves forward
- Transferse process push forward, force ribs into rotation, upper ribs move inferiorly
Lower Ribs
- Ribs ELEVATE, bottom ribs come up, upper ribs go down
Describe the biomechanics of thoracic extension
- Backbending and inhalation
- Posterior rotation and translation of superior vertebra on inferior vertebra
- Inferior facets slide down and backward on superior facets
Describe the coupled rib motion with thoracic extension
- Superior vertbral body motion causes posterior rotation of rib head (inferior demifacet attachment)
- Anterior portion of rib moves superiorly
Superior vert moves posterior -> rotates and translates posteriorly -> transverse process moves backwards -> pulls ribs and rotates posteiorly -> anterior ribs move superiorly
Upper ribs move up and loewr ribs go down
Describe the biomechanics for lateral flexion of the thoracic spine
- Lateral flexion in frontal plane/saggital axis
- Type 1 Mechcanics (rot - SB opposite)
Ipsilaetal compression
Downward glide
Opposite glide (opening)
Describe the biomechanics of thoracic rotation
- Roation occurs in transverse plane around vertical axis
- Type 2 mechanics (rot - sb SAME)
Rotation causes same side sidebending
Shift of vertebral body on L as rotates on R
Ribs on left rotate anterior to and get into FLEXION
Ribs on Right will posterior roate (elevate) and get into extension
What are the rib mechanics of respiration (motions, muscles)
- Rib motions: move as described in thoracic extension/flexion
- Primary muscles
- Diaphragm
- scalenes
- Intercostals
Whata re the muscels used for forced inspiration
Serratus posterior superior/inferior, levator costarum, SCM, latissimis dorsi, iliocostalis cervicis and thoacis, pec minor and major, quadratus lumborum
What are the muscles of forced expiration?
- Abdominals, transversus thoracic, internal intercostals
Describe the motion in the upper, middle, and lower ribs in respiration
- Upper
- Pump handle movement
- Changes A-P Diamter
- Middle
- Bucket handle movement
- Changes A-P and transverse diameter
- Lower
- Caliper like movement
- Changes transverse diameter
- (same as bucket handle elevation/depression) due to costotransverse formation)
What is considered the upper T spine?
- T1-3
- functions are part of the loewr C spine
- more flexion and ext (not a lot of sidebeing)
Treatment: use rotation and lateral flexion techniques
What is considered the lower T spine?
- T10-12
- Funtions are part of the upper L spine
treatment: use rotation and sidebending
What is considered the functional T spine?
- T4-9
- “true” T spine
- Greatest amount of movement is rotation = use flexion and extension techniqies
What are 2 common patterns of clinical presentation?
- Pain from loading - Load attenuation
- ex - sitting in awkward position
- Symptoms related to movement/motion restrictions (too stiff)
Where is most load on the T spine? How does the T spine handle load?
Increases caudally - significant load on T12 compared to T1
- Progressive increase caudally
- Vertebral body height
- End plate cross sectional area (thicker)
- Higher Bone content (esp last 6 segments)
How is load transfereed in the upper and lower T spine?
- Upper: load transferred thorugh vertebral body/disc complex
- Lower T spine: greater load transferred through posterior column via interlocking lamina and facet joints
Describe the IVD in load attenuation of the T spine
- Thinner than C spine and L spine disk
- Stronger annulus fibrosis (resistn rotational stress)
- More disc lesions
Which part of the T spine would undergo greater deformation and crep?
- Upper and mid thoracic discs
- more malleable
What is the difference between loading in the L and T spine
- L spine: compressive loading is equally distributed across surface of end plate independent of postion of motion segment
- T spine: loading distribution becomes asymmetric when loaded outside the neutral position
- may explain common findings of mid thoracic pain with sustained loading postures (driving, sitting, etc)
- being flexed for too long
- may explain common findings of mid thoracic pain with sustained loading postures (driving, sitting, etc)
How can an “habitually” flexed T spine affect other areas of the body?
- Normal mechanics/motion of the C spine and shoulder dependant upon normal mobility of upper T spine
- Habitually flexed
- reduced capacity of muscles to provide cervicothoracic retraction to work in the functional range
- Anteriorly rotated upper ribs will restrict range of C spine extension and rotation motions due to requrement of movement out of the neutral spinal alignment
- Therefore, greater demand on more mobil lower C spine segments and potential for symptoms/early degeneration
What is the importance of upper T spine extension
- required for bilateral shoulder flexion
- restricted motion can lead to subacromial pathology (altered scap/GH mechanics)
- Restricted upper rib mobility - sogns and symtpms consistent with subacromial impingement or thoracic outlet
What is the importance of mid T spine and motion restrictions
- Anterior elemts suvject to high comrpessive loads because of apex of kyphosis
- Excessive kyphosis from excesive loading = hypomobility of ribs
How does a PA mobilization on the spinous process move a segment?
- indueces anterior translation and posterior rotation (extension) of the related vertebral segment
Describe anteriorly applied PA to the thoracic spine?
- Upper T spine: T3 downward vector and superior vector
- Extension moement and anterior glide
- Lumbar/T9 - Vector produces extension moment
Describe spinal curvature PA in the thoracic spine?
- Straight PA glide (Translation)
Describe PA towards the center of vertebral body
- Extension moment in upper
- Flexion moement in lower
