Intro To VC Flashcards
What is the overall function of the vertebral column?
Required to meet the demands of mobility and stability of the trunk & extremities and protect the SC
How many vertebrae do we have and how many in each group
33 total
7 cervical 12 thoracic 5 lumbar 5 sacral 4coccygeal
How many intervertebral discs do we have?
23
What grouping of vertebrae are are considered primary (kyphotic) and which are secondary (lordotic)? And what are the advantages to these curves?
Primary - Thoracic and Sacral
Secondary - Cervical and Lumbar
Advantage - increased stability to resist compressive load
What allows for the spine to be considered a “functional unit”
Any 2 adjacent vertebrae (facet joints)
IV discs
Soft Tissue
Describe the anatomy of the “typical vertebra”
Anteriorly: vertebral body
Posteriorly: Vertebral or Neural arch
Posteriorly divides into pedicles and posterior elements (laminate, articulate processes, spinous process, and transverse process)
Composition:
Shell - compact bone
Interior - cancellous bone
What is the function of the vertebral body?
Weight bearing structure
What is the functional of the pedicles in the neural arch?
Transmit tension and bending forces from posterior elements to vertebral body
Describe the Laminae
Pars interarticularis - portion of laminae between superior and inferior articular processes
Subjected to bending forces
Describe the articular processes
2 superior facets and 2 inferior facets that make up zygapophyseal joint
What are all the posterior elements of the vertebral
Laminae
Articular processes
Spinous process
Transverse processes
Explain the clinical significance in regards to stress fractures at the pars interarticularis
Results in forward slipping of the vertebral which is known as spondylolisthesis
-most commonly occurs is L5/S1
General function of vertebral anatomy parts
- Body: resist compressive loads
- Pedicle: transmit the bending forces form the posterior elements to the vert. Body
- Laminae: transmit forces from the articular, transverse and spinous processes to the pedicabs
- transverse processes: serve as muscle attachment and provide mechanical level
- spinous process: serve as muscle attachment and provide mechanical level, also may serve as a bony block in motion
- vertebral foramen: combined with all segments, forms a passage and protection for the SC
IV Disc general structure
Consist of:
Nu. Pulposus
-70-90% water
Annulus fibrosis
- fibrous outer ring
- 60-70%
- collagen and elastin arranged in 15 to 25 concentric layers
Vertebral end plate
- cartilaginous layer covering sup. And inf. Surfaces if the disc
- strongly attached to annulus fibrosis but not the vert. Body
- high fx risk
IV Disc function
Separate 2 vert. Bodies — > increase the available motion
- available motion a reflection of ratio of disc ht to vert. Body ht - larger ratio = greater movement
Transmit load from 1 vert. Body to the next
Stabilization of the spine
Provide space between vertebra for exiting spinal nerves
What is the order (greatest to least) of ratios for available motion
Cervical, lumbar, thoracic
what % of force is transmitted through IV disc and what allows for this?
80%
Fluid property of the disc allows for uniform distribution of the force
What can the annulus fibrosis resist?
Distraction, shearing and torsion
When is disc pressure large in regards to load placement? What are ways to lessen and increase the pressure on disc
Disc pressure is large when holding load in front of the body, especially in forward bending
- lift load with knees flexed places less pressure compared to knees straight
- slouching produces greater disc pressure than sitting erect
What are interbody joints?
Joints between the vertebral bodies
-symphysis type cartilaginous jts
available motion:
- sliding (AP, ML & torsional)
- Distraction & Compression
- rotation/tilt (AP & Lateral Direction)
Total of 6 d.o.f
Facet Jts articulations
Articulation of superior articulation facets with inferior articulating facets of vertebra
-determine direction of vertebra
Facet Jt highest strength and what/where does it restrict movement
Highest in thoracolumbar and cervicothoracic junction
-limits motion and adds to stability
-primary restraint to cervical rotation and side bending
-primary restraint to lumbar rotation
-vulnerable to hyper Flexion
9cause capsule to rupture)
What are the kinematic motions of the vertebral column?
Flexion, extension, lateral flexion and rotation
What is unique when it comes to kinematic motions? What is the prime example?
These motions are often coupled
Example: lateral flexion and rotation
What is coupling?
Consistent association of one motion about an axis with another motion around a different axis
What does the IV disc do in regards to kinematic
- Increases movement between 2 adjacent vertebra
- allows for vertebra to rock/tilt on each other secondary to deformable disc between them
- adds significant ROM
- the annulus fibrosis acts to restrain motion
What do interbody joints do in regards to kinematic
Determine magnitude of movement
Distribute load
Create space for movement and passage of the spinal nerve roots
What do facet joints do in regards to kinematic
Determine direction of movement
Influenced by bony geometry, height and spatial orientation
What is osteokinematics
Description of movement based on direction of superior segment’s anterior portion
Flexion/extension
Lateral flexion/side bending
Rotation
What are the kinematic motions of flexion
Anterior tilt and anterior glide of the superior vertebra
- results in widening of the intervertebral foramen and separation of spinous processes
- results in anterior compression of the annulus fibrosis and posterior stretching of the annulus fibrosis
What are the kinematic motions of extension?
Posterior tilt and posterior glide of the superior vertebra
- results in narrowing the intervertebral foramen and spinous processes
- results in posterior compression and anterior stretching of the annulus fibrosis
What are the kinematic motions of lateral flexion
Lateral tilt, rotation and translation of the superior vertebra over the vertebra below
- results in widening of the intervertebral foramen on the side contralateral to the lateral flexion and narrowing on the i psi lateral side
- results in compression of the annulus fibrosis on the ipsilateral side of movement and stretching on the contralateral side of movement
- direction of rotation differs slightly in different regions because of the orientation of the facets
What are the kinematic of rotation
Varies widely by region
Rotation of interbody joint
Approximation/distraction at the facet joints
What are the forces that VC are subject to
Axial compression Tension Bending Torsion Shear
These all happen also at rest
Functions of spinal musculature
- Control posture
- Stabilize axial skeleton
- Protect spinal score and internal organs
- Generate intro-thoracic & intro abdominal pressure
- produce torque for movement of the body
- mobility of head and neck for optimal place of eyes, ears & nose
