Thoracic Spine Flashcards
Which region of the spine is the stiffness and least mobile? Why?
thoracic spine, due to the rib cage
Each thoracic vertebrae is involved in how many articulations?
at least 7 and as many as 13
What 2 things cause thoracic kyphosis?
- lesser anterior height of the thoracic vertebral body
- slight wedge shape of the thoracic discs (2mm higher posteriorly)
The apex of the thoracic kyphosis occurs at what spinal level?
T7-T8 (T6-7?)
The average thoracic kyphosis ranges from ___-__ degrees
20-40
Which thoracic vertebrae are typical and which are atypical?
T2-T10 are typical
T1 and T12 are atypical
Describe the shape of the thoracic vertebral bodies
Circular almost in that they are roughly as wide as they are long with the AP and ML dimensions equal
The anterior surface of the thoracic vertebral bodies are con__ the posterior surfaces are con__.
convex
concave
The vertebral bodies from T2-T10 _____ in size and change shape as you move caudally
increase
In comparison to the remainder of the spine the IVDs of the thoracic spine are _____ and _____.
narrower and flatter
The IVDs constitute approximately how much of the length of the thoracic spine?
1/6th
Nerve roots in the thoracic spine are situated behind the inferior-posterior aspect of the upper vertebral body rather than then disc, why is this?
It decreases the risk of root compression
The spinal canal in the thoracic spine is relatively narrow, especially between what spinal levels?
T4-T9
At T_ there is a significant decrease in movement of the spinal cord in relation to the surrounding structures. What does this lead to?
T6
The creation of a tension point
What is the clinical significance of tension points?
Because they are vulnerable sites within the nervous system, they cause a variety of complaints
The TPs of the thoracic spine are ___ with their corresponding vertebral body
level
What is difference about the transverse process of T1-T10?
They possess a concave joint surface for articulation with the ribs
(T11 and T12 do not have castal facets)
In what direction do the first 3 and last 3 spinous processes face?
almost horizontal
The long spinous processes from T4-T9 face what way?
steeply inclined downward
The spinous processes of the thoracic spine are designed to do what?
to endure and distribute the compressive forces produced by weight bearing
At T1 the compressive load is approximately _% of body weight, at T8 it is approximately __%, and at T12 it is approximately __%.
9
33
47
The spinous processes from T1-T3 are level with what?
their own vertebral body
The spinous processes from T4-T6 are level with what?
the IVD
The spinous processes from T7-T9 are level with what?
the transverse processes of the vertebral body below it
The spinous processes from T10-T12 are level with what?
the same plane as the transverse processes
Describe the orientation of the upper and lower thoracic facet joints
The upper facet joints resemble the cervical facets
The lower facet joints resemble the lumbar facets
Due to thoracic cage articulations _____ plane motions are limited while _____ plane motions are accommodated
sagittal
axial
What direction do the superior articular facets face?
Posterior
Lateral
Superior
What direction do the inferior articular facets face?
Anterior
Medial
Inferior
The thoracic facet joints face __-__ degrees away from the frontal plane
20-30
What ribs are true ribs?
ribs 1-7
What ribs are false ribs?
ribs 8-12
Where do the false ribs attach distally?
to the costochondral cartilage of their superior neighbor
Which ribs are typical?
3-9
What is a typical rib characterized by?
a posterior end, which is composed of a head, neck and tubercle