TS Anatomy Flashcards
Unique features of thorax - in one typical vertebra (T2-T9) there will be 12 separate articulations for what structures?
- superior articular processes (2) for facet joints above
- inferior articular processes (2) for facets joints below
- superior demi-facets (2) for costovertebral joints
- inferior demi-facets (2) for costovertebral joints
- transverse process facet (2) for costotransverse joints
- intervertebral joints (2)
Relative stability of the TS compared to the LS & CS is due to:
- rib cage (increase stability of unit nearly 3x & greatly decrease mobility)
- attachment of rib head to intervertebral disc
- angulation of facets & decreased disk height
T/F: any movement occurring at any joint of each ring (costovertebral, costotransverse, sternocostal or facet joint) can potentially influence motions at the other joints within the ring or adjacent segments.
True
Why is the integrity of the thoracic ring important?
-it is critical to the stability of the thorax
Which other musculoskeletal dysfunctions can the thoracic spine contribute to?
- shoulder
- AC/SC
- neck
- lumbar
What are the functional regions of the thoracic spine?
- cervicothoracic junction (CT junction)
- middle thoracic spine
- thoracolumbar (TL) junction
What are the segments that make up the cervicothoracic (CT junction)?
-C7 through T3
What are the segments that make up the middle thoracic spine?
-T4 through T9
What are the segments that make up the thoracolumbar (TL) junction
-T10 through L1
Anatomy of the vertebromanubrial region (classified by Diane Lee)
-upper thorax, T1-2 + Rib 1-Rib 2 + manubrium
Anatomy of the vertebrosternal region (classified by Diane Lee)
-middle thorax, T3-T7 + Rib 3-Rib 7 + sternum
Anatomy of the vertebrochondral region (classified by Diane Lee)
-middle/lower thorax, T8-T10 + Rib 8 - Rib 10
Anatomy of the thoracolumbar region (classified by Diane Lee)
-lower thorax, T11-12 + Rib 11 - Rib 12
Anatomical orientation of the vertebral bodies and intervertebral discs in the thoracic spine?
-vertebral bodies & intervertebral discs are higher posteriorly than anteriorly
How does the anatomical orientation of the vertebral bodies and intervertebral discs affect the load on the vertebral body in the TS?
-since both structures are higher posteriorly than anteriorly, there is increased load ventrally on the vertebral body
How do the vertebral bodies in the TS compare to the vertebral bodies in the LS?
-TS vertebral bodies are more wedge-shaped
Which thoracic vertebrae are considered typical in reference to their morphology?
T2-T9
Which thoracic vertebrae are considered atypical in reference to their morphology?
T1, T10, T11, T12
Which structures form the costovertebral joint (CVJ)?
-formed by the articulation between the head of the rib, the intervertebral disc and the vertebral body at the same level and the level above
Anatomical variations in T1?
-two ovoid facets for articulation with Rib 1 with two small demi-facets on the inferior aspect of the body for articulation with Rib 2
Anatomical variations in T9 and T10?
- T9 has two demi-facets for articulation with rib 9 & often, there is a small articulation between the superior aspect of the head of the 10th rib & the inferior aspect of the vertebral body of T9.
- occasionally, the 10th rib will articulate only with T10
Anatomical variations in T11 and T12?
-rib 11 and rib 12 articulate only with the vertebral body at the same level
Disc height ratio comparison between TS, CS and LS?
TS = 1:5 CS = 2:5 LS = 1:3
Why is it typical to see central disc protrusions of the annular type and not nuclear?
-the nucleus in the TS is so small
Schmorl’s nodes
-herniation of disc substance through cartilaginous plate of disc into the body of the adjacent vertebra
Why does a patient complain of band of pain with damage to the outer annulus of the intervertebral disc?
-poly-segmental innervation (patient will complain of band of pain)
Why does a patient complain of thumbprint pain with damage to the inner annulus of the intervertebral disc?
-mono-segmental innervations (thumbprint pain)
How does the ALL differ in the TS compared with the CS & LS?
-the TS ALL is narrower but thicker relative to CS & LS
TS anterior compartment structures?
- vertebral bodies
- intervertebral discs
- ligaments (ALL)
What structures form the vertebral arches in the TS?
-the lamina & pedicles
Function of the vertebral arch?
-protects spinal cord
Where is the spinal canal smallest?
-middle thoracic segments (T4-T9)
What junctions have large spinal canals?
- cervico-thoracic junction
2. thoraco-lumbar junction
TS lamina
-when disc protrudes dorsally there is no chance for other structures to move out of the way. a very small protrusion of the disc can cause immediate dural irritation
TS pedicle
-located cranial, short & thick
T/F - it is common to have facet orientation asymmetry in the TS
true
Upper facet segments orientation:
-45-60 degrees from horizontal in the coronal plane
Middle facet segments orientation:
-50-60 degrees from the horizontal in the coronal plane (or 20 deg. in the transverse plane)
Lower facet segments orientation:
-inferior facets of T11 and T12 can resemble lumbar Z joint (in sagittal plane) changing by 90 degrees
Convex/concave rule for TS facet joints
-superior facets are slightly convex & inferior facets are slightly concave
Facet joints innervation for TS?
-medial branch of dorsal rams, supplied by axons from 1 to 2 adjacent root levels above, the same level & 1-2 levels below
Description of spinous processes?
-long (5-6 cm), slender & triangular shape
Function of spinous processes?
-increase inferior angulation
Location of transverse process in relation to spinous process for T1-T3?
-TP is directly lateral to the SP
Location of transverse process in relation to spinous process for T4-T9?
-TP is superior to the SP (as many as 3 fingers)
Location of transverse process in relation to spinous process for T10-T12?
-gradual transition of TP lateral to SP
What forms a costotransverse joint (CTJ)?
-formed when the ribs attach to the transverse process via the costotransverse ligament
PLL of TS?
- thicker in thoracic region
- wider at disk level & narrower at vertebral body
Ossification of PLL & Ligamentum Flavum
-middle & low back pain, difficulty with balance, progressive gait disturbance, onset of bladder retention, MRI & CT sensitive
Rx for ossification of PLL & Ligamentum Flavum?
-a decompressive laminectomy
What motion does the facet capsule limit?
-TS flexion
intertransverse ligament
-attach TP to TP
costotransverse ligament
-in costotransverse foramen (interval between neck of rib & anterior surface of associated transverse process; attach rib to TP
lateral costotransverse ligament
- short & thick
- apex of transverse process to non-articulating portion of tubercle of adjacent rib
superior costotransverse ligament
-anteriorly between neck of rib & lower aspect of superior transverse process; laterally continuous with intercostals membrane, posteriorly attaches to posterior aspect of neck of rib & transverse process
intra-articular costovertebral joint
-from head of rib between facets to the disc in the CVJ; divides joint into 2 cavities
radiate ligament of costovertebral joint
-attaches the head of the rib to the disc
True ribs
ribs 1-7
considered true ribs because their cartilage attaches directly to the manubrium or sternum
How do the true ribs affection motion in the thoracic spine?
- increases flexion/extension stiffness
- no change in rotation
Rib 1
- atypical
- shortest of the 12 ribs; articulates with the manubrium; the sternochondral joint is fibrous rather than synovial
Rib 2
- atypical
- articulates with manubrium & sternum at manubriosternal symphysis (synovial joint)
Rib 3-6
- typical
- the sternum has 8 full concave facets for articulation with the costocartilage of rib 3-rib 6 (synovial joints)
Rib 7
- typical
- articulates with sternum & xiphoid process
False ribs
- ribs 8-10
- articulate indirectly with the sternum by blending with the seventh costocartilage through the chostochondral cartilage of their superior neighbor
How do the false ribs influence motion at the thoracic spine?
-increase stiffness with rotation with more ability to move in flexion & extension
Ribs 8-9
-typical
Rib 10
- atypical
- articulates with corresponding vertebral level, articulation to TP is variable
Ribs 11-12
- atypical
- no sternal attachment, articulate with corresponding vertebral level but not to the TP of that level
Movement of ribs during breathing?
- upper: pump
- lower: bucket
- ribs 1-2: don’t move as much
- ribs 3-6: move more in A-P direction (pump)
- ribs 7-10: move more in lateral direction (bucket)
Ribs 1-4 elasticity
-stiff, strong, rigid, relative immobility
Ribs 5-12 elasticity
-greater elasticity, fracture potential
Definition of “typical” ribs?
- Ribs 3-9
- posterior end has a head, neck & tubercle. The head has two articular facets (superior costal facet for articulation with vertebral body above & inferior costal facet for articulation with vertebral body below)
Definition of “atypical” ribs?
- Ribs 1, 10, 11, 12
- they only articulate with their own vertebrae via one full facet
Thoracic spine biomechanics general concepts?
-when compared to other regions of the spine, literature regarding the biomechanics of the thoracic spine has not been extensively published. much of the available research is based on observation & empirical data rather than on laboratory studies
TS sagittal plane physiological movement?
- 20-45 degrees of flexion
- 15-20 degrees of extension
TS frontal plane physiological movement?
-24-45 degrees of total SB movement
TS transverse plane physiological movement?
-35-50 degrees of total rotation movement
Upper TS facet joint orientation?
-45-60 degrees to coronal plane
Middle TS facet joint orientation?
-90 degrees to coronal plane/20 degrees to transverse plane
Lower TS facet joint orientation?
-0 degree to coronal plane (starts to change from coronal to sagittal plane)
How does movement in the C-spine cause movement up/down the kinematic chain?
-causes movement down to T3-4
How does movement in the UE cause movement up/down the kinematic chain?
-causes movement down to T5-6
How does movement in the LE cause movement up/down the kinematic chain?
-causes movement down to T7-8
How does movement in the UE/LE (during gait) cause movement up/down the kinematic chain?
-causes movement down to T6-8
TS disc mechanics?
- primarily controls rotation & extension
- minor control of flexion & SB
Flexion osteokinematics in a mobile thorax?
-anterior translation coupled with forward sagittal rotation induces anterior rotation of the ribs
Flexion arthrokinematics of the vertebra in a mobile thorax?
-interior facet of the superior vertebra glides superior-anteriorly at the facet joints
Flexion arthrokinematics of the rib in a mobile thorax?
-convex tubercle of the rib glides superiorly on the concave transverse process of T3-T7 in response to the anterior rotation of the rib - convex on concave
Flexion osteokinematics in a stiff thorax?
-ribs are less mobile
Flexion arthrokinematics of the vertebrae in a stiff thorax?
-the arthrokinematics are the same as a mobile thorax with the exception that the degree of anterior translation is less
Flexion arthrokinematics of the ribs in a stiff thorax?
-ribs are less mobile, during forward bend the anterior aspect of the rib travels inferiorly while the posterior aspect travels superiorly. once the mobility of the rib cage is exhausted, the thoracic vertebrae continue to flex on the stationary ribs
Flexion osteokinematics of a rigid thorax?
-the relative flexibility between the vertebral column & the rib cage is the same, no palpable movement between the thoracic vertebrae & the ribs
Flexion arthrokinematics change in the vertebrae of a rigid thorax?
-some superior gliding but little anterior translation
Limiters of TS flexion?
- posterior ligaments
- posterior 1/2 of disc
- facet joints & CVJ
Extension osteokinematics in a mobile thorax?
- posterior translation coupled with backward sagittal rotation
- induces posterior rotation of ribs
Extension arthrokinematics of the vertebrae in a mobile thorax?
-inferior facet of superior vertebra glides infero-posteriorly at the facet joints
Extension arthrokinematics of the ribs in a mobile thorax?
-convex tubercle of the rib of T3-T7 glides inferiorly on the concave transverse process of T3-T7 in response to the posterior rotation of the rib
Extension osteokinematics of a stiffer thorax?
-ribs are less mobile
Extension arthrokinematics of the vertebrae in a stiff thorax?
-same as in a mobile thorax BUT degree of posterior translation is less
Extension arthrokinematics of the ribs in a stiff thorax?
-ribs are less mobile, during backward bend the anterior aspect of the rib travels superiorly while the posterior aspect travels inferiorly. once the mobility of the rib cage is exhausted, the thoracic vertebrae continue to extend on the stationary ribs
Extension osteokinematics in a rigid thorax?
-the relative flexibility between the vertebral column & the rib cage is the same, no palpable movement between the thoracic vertebrae & the ribs
Extension arthrokinematics changes in the vertebrae in a rigid thorax?
-some inferior gliding but little posterior translation
Limiters of TS extension?
- ALL
- anterior 1/2 of disc becomes taught
- compression of the posterior disc & PLL
- contact by either the SP or the facets
Biomechanics of side bending in the cervicothoracic region (up to T2)?
-side bending is accompanied by rotation to the same side
Osteokinematics of side bending in the TS?
-in both the mobile & stiff thorax the ribs stop moving before the thoracic vertebrae
Arthrokinematics of the facets during side bending?
-whichever side the TS is bending to (right side, for example), the right inferior articular process of the superior vertebra glides inferiorly & the L glides superiorly
Silent zone (described by Diane Lee) for side bending?
-coupling pattern is not always contralateral & can be ipsilateral. careful examination of 3D movements & PPIVM testing will help guide the clinician in determining the coupling pattern for individual patients
Thoracolumbar side bending biomechanics?
-differing reports: side bending is accompanied by rotation to the opposite side vs. Diane Lee reports that pure SB occurs at the TLJ
Limiters of TS side bending?
- soft tissue
- ribs
- ipsilateral facet approximation
TS side bending influence with breathing?
-active SB towards the pain: increased pain with inspiration: ribs
Osteokinematics of rotation in thoracic spine?
-coupled with ipsilateral SB
Arthrokinematics of rotation (described for right rotation)?
-R inferior aspect of superior facet joint moves infero-medially & L moves supero-laterally
Limiters of TS rotation?
- anterior chest
- stable disc
- rib cage
Anterior thoracic spine muscles
- scalene
- abdominals
- serratus anterior
- pectorals (all attach to ribs)
Posterior superficial thoracic spine muscles?
- spinalis thoracis
- longissimus thoracis
- iliocostalis thoracis
- quadratus lumborum
- multifidus
Posterior deep thoracic spine muscles?
- rotators
2. multifidus
