Anatomy Midterm 2 - Vertebral Column Flashcards
Where do about 95% disc herniation occur?
lumbosacral region due to the great forces placed on them
What are the types of curvatures of the vertebral column?
Primary (kyphosis) - Thoracic and sacral
Secondary (lordosis) - Cervical and lumbar
What is scoliosis?
lateral displacement of vertebral column
Where are IVD found?
Present between vertebral bodies of C2 to sacrum
Where is the IVD thickest?
Thicker anteriorly; Thicker in cervical and lumbar regions;
What’s unique about IVD in the thoracic region?
Nearly flat and discs are thinnest in upper thoracic
What is the hyaline cartilage called in the IVD?
vertebral end plate
What are the 3 regions of the IVD?
1) Narrow outer collagenous zone
2) Wider, inner fibrocartilaginous zone
3) Annulus fibrosis (consists of a number of laminae)
What imparts great torsional strength on disk?
Oblique arrangement of fibers
What way do the outer laminae bulge?
Externally
What way do the inner laminae bulge?
Internally toward the nucleus pulposus
What are the functions of Annulus fibrosis?
Enclose and retain nucleus pulposus
Absorb compressive shock
From structural unit between vertebral bodies
Allows restricted motion
What are the functions of the inner nucleus pulposes?
40% of the bulk of the disk
Contains remains of notochord
Better developed in cervical and lumbar regions
Lies more posteriorly
Decreases in size with age
Allows movement between vertebral segments
What are the notochordal cells replaced with during the first decade of life?
fibrocartilage
What ligaments are attached to the IVD?
ALL and PLL
Are IVD avascular?
Yes, except for the periphery
What is a herniated disc?
Occur when the nucleus is extruded through a defect in the annulus.
Where is a herniation likely to occur on the vertebral body? Why?
Posterolateral, because annulus is thinnest posteriorly and the PLL reinforces the annulus directly posteriorly
What innervates IVD?
Posteriorly - recurrent meningeal nerve
Posterolaterally - ventral rami and gray rami communicantes
Anteriolaterally - gray rami communicantes and branches of sympathetic trunk
What are the features of ALL?
Syndesmosis
Narrow cranially and broader caudally
Between C0-C1 anterior atlantooccipital membrane
Between C1-C2 anterior atlantoaxial membrane
What are the features of the PLL?
Syndesmosis
C2-Sacrum
Broader in upper cervical and thoracic
Above C2 becomes Tectorial Membrane
What are the features of zygapophyseal joints?
Plane synovial Joints
May contain fat pads or fibroadipose in lumbar region
Innervated by: medial branches of dorsal rami
What are the Intervertebral (segmental) syndesmoses?
Ligamenta flava (segmental syndesmosis) Interspinous ligaments (segmental syndesmoses)
What are the continuous (nonsegmental) syndesmoses?
Ligamentum nuchae
What innervates the intervertebral joints?
Innervated by adjoining spinal nerve
What are craniovertebral joints?
Atlantoaxial joints
- Lateral AA joint
- Median AA joint (trochoid joint) - cruciate ligament
What are the 5 principal movements of the vertebral column?
Flexion, extension, lateral flexion, rotation, circumduction
Degrees of Flexion/Extension
Cervical - 15 degrees
Thoracic - 4 degrees in upper; 12 degrees in lower
Lumbar - 15 degrees; 75% of all flexion/extension in vertebral column
Events that occur during flexion
ALL relaxed Disks compress anteriorly Laminae and spinous process spread apart Dorsal ligaments tensed Extensor (erector spinae) muscles resist flexion
Events that occur during Extension
ALL & anterior fibers of annulus fibrosis tense
Disks compress posteriorly
Spinous processes & zygapophyseal approximated
Greatest extension in lumbar region
Degrees of lateral flexion
Cervical - 10 degrees
Thoracic - 6 degrees
Lumbar - 6 degrees
Degrees of rotation
Cervical - moderate (C1&C2 80 degrees to one side)
Thoracic - greatest
Lumbar - least
What are the majority of vertebrates?
90% are fish
