Vertebral column Flashcards
The vertebral column is made up of 5 structures.
What are they?
How many vertebrae in each?
Cervical spine (7) Thoracic spine (12) Lumbar spine (5) Sacrum (5, fused) Coccyx (4, fused)
Describe the curvature of the vertebral column.
Why does it curve in this way?
Alternating pattern of lordotic (concave posteriorly) and kyphotic (concave anteriorly). Lordotic - CS Kyphotic- TS Lordotic- LS Kyphotic- Sacrum
Alternating curves balance each other to create a stable system which maintains the COG in a balanced state
How does the cervical spine curve?
Lordotic (concave posteriorly)
When do the vertebral curvatures develop?
Kyphotic curvatures (thoracic spine and sacrum) develop in utero. Lordotic curvatures (cervical and lumbar spine) develop during childhood; associated with lifting the head and sitting upright.
How are the sacrum vertebrae (structure) adapted for function?
Fused, widened and concave anteriorly to transmit the weight of the body through the pelvis to the legs
What are the 4 functions of the vertebral column?
1) Protect the spinal cord and cauda equina
2) Support the weight of the skull, thoracic cage, upper limbs and pelvis.
3) Contribute to movement and posture
4) Provide a site of haematopoiesis
What shape is the lumbar vertebral body?
Kidney bean shaped
The vertebral bodies change size throughout the vertebral column. Why is this?
Bodies increase in size inferiorly to resist growing compression forces due to increasing load above
The vertebral body is largely made up of which type of bone?
90% cancellous, 10% cortical
Describe the vertebral end plates
Superior and inferior surfaces of the vertebral body. They’re coated in hyaline cartilage and are adjacent to intervertebral discs
What is the major load bearing structure in the vertebral column?
What is the minor?
Vertebral bodies carry 2/3rds of the load
(except in atypical C1 & C2)
Posterior elements carry 1/3rd
What are the posterior elements?
Everything posterior to the vertebral body
Which structures make up the vertebral arch?
What is the purpose?
The 2 lamina and 2 pedicles.
The lamina connect the transverse processes to spinous process.
The pedicles connect transverse processes to the vertebral body.
The arching shape creates a tunnel for the spinal cord to sit inside
How many processes are there on the lumbar vertebra?
Name them.
7 processes spinous (1) Transverse (2) Inferior articular processes (2) Superior articular processes (2)
Why do muscles and ligaments attach to the spinous and transverse processes?
To control the position of the vertebral bodies; to allow movement etc.
What is another name for the zygapophyseal joint?
What type of joint in this?
Facet joint
Its a synovial joint due to hyaline cartilage coating of the inferior and superior articular processes which make up the joint.
Where does the spinal cord terminate?
L1-2
The vertebral notch creates which foramen?
How?
The intervertebral foramen where nerves can exit the spinal cord to the periphery
The notch is the concave shape of the articular processes. When they articulate in the facet joint, a hole is created.
The facet joint prevents displacement of the vertebrae in which direction?
Antero-posteriorly (forward- backward)
What determines the movement permissible at the facet joints?
The angle of the articulating facets (surfaces)
The invertebral discs make up how much of the vertebral column? (fraction)
1/4
What’s the major component of intervertebral discs?
What are the 2 other components?
Water 70%
collagen 20 %
proteogylcans 10%
What are the two regions of the invertebral discs and where are they located?
Annulus fibrosus is the peripheral/ outer layer around the circumference
Nucleus pulposus is the central inner section
How is the annulus fibrosus adapted for function?
Made up of lamellae of annular (ring shaped) collagen in varying orientations which allows the disc to resist compressive (axial) forces
(Function is a shock absorber)
The intervertebral disc will not fracture under compressive forces. Which other vertebral structure will?
Why?
The vertebral body
It is the major load bearing structure within the column and is weaker than the discs (concerning axial (compressive) forces).
Name the three collagen types within the intervertebral discs and their locations.
Annulus fibrosus:
Outer lamellae- Type 1 collagen
Inner lamellae- fibrocollagen
Type 2 collagen in the nucleus pulposus
The nuceus pulposus is gelatinous. Why?
How does its location change from infancy?
Type 2 collagen within the nucleus has a high osmotic content because water resists compressive forces.
Centrally located in child, becoming more posterior.
Why does the vertebral column shorten throughout the day?
When else does it shorten?
Water is forced out of the nucleus pulposus (within the intervertebral discs) throughout the day due to mechanical pressures
Column shortens with age