Biomechanics and Kinesiology of the Thoracic Spine PDF

Biomechanics and Kinesiology of the Thoracic Spine Stephanie Muth, PT, PhD & Thoracic Spine Most stable part of vertebral column –Longer spinous processes, thoracic cage articulations, numerous and well developed ligaments, facet joints Longest region of ve...

Biomechanics and Kinesiology of the Thoracic Spine Stephanie Muth, PT, PhD & Thoracic Spine Most stable part of vertebral column –Longer spinous processes, thoracic cage articulations, numerous and well developed ligaments, facet joints Longest region of vertebral column Minimal mobility at individual thoracic segments ↓ mobility Stability –Multiple thoracic segments moving in concert allows for a larger ROM Stable base for head and arms –Stability for UE movements Protection –Spinal cord –Internal organs V would conpress Thoracic Cage Formed by: thoracic vertebrae, 12 pairs of ribs, and sternum Functions: Rigid for protection of heart & lungs Flexible to allow respiration and spinal motion Rib cage supports entire thoracic spine Sustain 4x compressive load with intact cage Without cage, T/S vertebrae alone would barely be able to support weight of head Thoracic spine- Facet Orientation Upper to mid thoracic spine Oriented between transverse and frontal planes; similar to lower cervical facets (gradual increase in inclination towards frontal plane) Rotation is dominant motion in upper & mid thoracic region Attachment of the ribs limits side bending and rotation Mid to lower thoracic spine ~ // – Oriented more in sagittal plane; similar to upper lumbar facets – Flexion/extension bias  Body –Sagittal plane: wedge wedge-shaped Primary cause for normal kyphosis –Transverse plane: Heart shaped Key joints IVD Blu ad jaat Costovertebral jnta -Articulationhasial joint blu ridt Trans process , ↑ - by -Po to lower Costosternal Joint sternum ribs > blu + - Key support structures > - reinpors facet joi  2 Attachmets Costal joint support blu rids & Topi Costotranverse joint support Key Support Structures Bats LF Anterior longitudinal ligament (ALL) Posterior longitudinal ligament (PLL) Ligamentum flavum (LT) patf ALL Intertransverse ligaments (ITL) Interspinous ligaments (ISL) Supraspinous ligaments (SSL) Anterior Middle Posterior What does “normal” movement look like? KINESIOLOGY Thoracic spine motion region 3lowerresembling Thoracic Spine Motion Lateral flexionCratmuch) ≤ 2 degrees More motion lower thoracic spine (T10-L1) Rotation Glitche 1 – 3 degrees Less motion lower thoracic spine (T10-L1) Normal joint kinematics Roll /Inf glide v - Post struct Post Compression is caused in/ - ↓ Ant. W > IV - Foramen gets V bigger as you > Flex. - offers releif Passive structures being elongated > - PLL, SSL  C Frontal plane C · In should be -> Vertebrae fairly vertical Movement coupling Studies disagree on coupling patterns in T-spin Coupling with structural scoliosis Ca. k. a Frontal Plane Deviation) - Aorta har) Ascending is on compressed (seeing · issues Foram is left Side Left IV C D R community Y. R Scoliosis causing Leftv... & Left side is compressed & Right is elongated. convex Ribhunf concave y > - on side of convexity. - lat rotation & Flex coupled ↳ showing opporte girls · controlaturally of ↳ Left Scoliosis. towards side of convexity(R ). BIOMECHANICS Muscle activity Erector spinae Eccentricallyconcentrically - How are they acting during flexion? Extension? How is motion controlled/initiated during electric silence? is here > - non-contractile If pain seen tissue might be a n issue - If you strain an Erector Spinasalivation. At this point , the resting on Y your contractesa ~or ↑ generate ↳ These tissue enough tension Normal kinetics (Thoracic Kyphosi)s MA - increases more causing Torque - to be ant. & creates a flexion Axis of rotation is going - Kyphosis moment (T) bk. of the KINEMATICS OF VENTILATION  Rib Motion WHEN THE RIBS ARE ELEVATED in THE sagittal plane, ANTERO- POSTERIOR DIMENSION OF THE THORAX IS INCREASED Flex & ext on. the vertebrae Elevation > A-P - increases Size WHEN THE ANGLES OF THE RIBS ARE ELEVATED in the frontal plane, THEY MOVE LATERALLY, INCREASING THE TRANSVERSE DIMENSION of the Thoracic cage Both frontal and sagittal plane motion occurs in lower ribs Rib Motion Torsion allows for storage of energy, released during recoil – allows for exhalation without msc contraction > - elastic recoil of connective tissue (no primary musc of expiration) Mechanics of ventilation The Diaphragm  & Transverse length increase - Descent of the diaphragm increases intraabdominal pressure which stabilizes the central tendon; continued contraction of the costal fibers results in the bucket handle action of the lower ribs concentricallcontracts Diaphragm pulls -down (nor so more space ing contract > ↑ Intra ) Abd-murcls neds to > Abdominal Pressure ↓ Pusher 12 ritsuf Normal mechanics during inspiration based on normal compliance of the abdominal wall Spinal cord injury heanation E affecting abdominal musculature INCREASES compliance a preated places - b Conditions such as pregnancy and abdominal obesity DECREASE compliance Eincrease tension by they are over elongated  Flattened diaphragm as seen with hyperinflated Normally inflated Chronic Obstructive lungs to COPD, consider the - Pulmonary lungs; observe the orientation of the muscle orientation of the fibers muscle fibers oriented Horizontally the lower Diaphagmatic contraction 2 : pulls ribs closer & lowes can actually decrease the the /S lung vol. Chyperinflationi size of the thoracic cavity  Activate Function is complex and to thoracic top to somewhat controversial upper thoracic Activated cranial to caudal> - lower botton Lower intercostals typically activated ↓ only with deep inhalation Primary function of parasternals likely stabilization of rib cge 1⁰ inspiratory muscles Play a role in elevation of 1st and 2nd ribs and sternum to create pump handle motion Ant & middle scalne attaches o 1st Rib- Post Scaline attach to 2nd Rib In the Sealenc interval is the brachial Plexus & subclavian A Conclusion Motion in this region is small and sometimes subtle Motion is critical to vital functions such as respiration Motion is an intricate interplay between all of the joints of the thoracic cage Abnormal postures can significantly alter the forces acting on the spine