Lecture 21 - Back and Vertebral Column Flashcards
What are the intervertebral disks made of?
Fibro cartilage
What are the components of the back?
From where does it run?
From T1 to coccyx
Consists of:
- axis / vertebral column (intervertebral disks, intervertebral foramen)
- muscle (deep, superficial)
Where is the spinal cord located?
Posterior to the vertebral column
Where does the spinal cord terminate?
Between L1 and L2
What are the four divisions of the spinal cord?
How many segments are in each?
Cervical : 7 Thoracic : 12 Lumbar : 5 Sacral: 5 coccygeal : 4
Describe how the curvature of the spine arises
Primary C curve: As a foetus
In utero: head muscle strengthen –> curve at neck
Baby: leg muscles strengthen –> curve at lumbar region
What are the curves in the spine called?
Lordosis
What is it called when there is abnormal curvature of the spine?
Give some examples of conditions in which this occurs
Abnormal lordosis
- Scoliosis
- Kyphosis
What are some features of a typical lumbar vertebra?
- Vertebral arch
- Pedicel
- Lamina
- Spinous process
- Transverse processes
- Articular process
- Vertebral body
- Vertebral canal
What is different about lumbar and thoracic vertebra?
Lumbar:
- larger, because they carry more weight
- no facets for ribs
Thoracic: facets for rib attachment
What are the names of the facets for rib attachment?
Articular facet
Articular Demi facet
Where does the head of the rib attach?
Articular demi facet
What attaches to the Articular facet?
Tubercle of rib
Where is the vertebral canal?
What is inside?
In between the vertebral body and the vertebral arch
The spinal cord runs down until L1-L2
From which angles are the vertebral column and the intervertebral foramen visible?
Vertebral column: looking vertically down
Intervertebral foramen: looking horizontally across the spine
What is in the intervertebral foramen?
Spinal nerve
Posterior root ganglion
What are the two roots of the spinal cord?
Posterior: sensation
Anterior: motor
Where are the cell bodies of the neurons connecting to the spinal cord?
Sensory neurons: Posterior root ganglion
Motor neurons: Anterior horn
What are the joints within the spine?
The intervertebral disks
What is the intervertebral disk made up of?
Annulus fibrosus
Nucleus pulposus
What are the features of the nucleus pulposus?
Deformable
Incompressible
What is the role of the intervertebral disk?
- Keeps the vertebrae apart
- Weight bearing forces – resisted by the annular fibres
What are the compositions of the nucleus pulposus and annulus fibrosus?
Nucleus: jelly like
Annulus: fibrous layers – not all in the same plane
Like an onion
What type of joint are the intervertebral disks?
Secondary cartilaginous joints
What is the role of ligaments in the spine?
Support
Limits the range of movement
What are the two ligaments found in the spine?
Where are they located?
Posterior longitudinal:
Running down the back of the vertebral bodies
Ligamentum flavum:
In between the pedicles
How does structure relate to function in the ligamentum flavum?
Elastic fibres – stretching of the spine during flexion of the body
What types of joints are the joints of the vertebral arches?
Where are they?
Synovial plane joints
On the articular processes
Describe the attachments of superficial back muscles
Originate on spine
Insert on limbs
Describe the attachments of deep back muscles
Originate and terminate on the spine
What are some of the muscles in the back.
Locate them
Levator scapulae
Latissimus dorsi
Rhomboids
Trapezius
What are some of the intrinsic muscle of the back?
What are their functions?
Erector spinae: runs up the back of the spine at keep the body erect
Transversospinalis: short muscles
- Fixators that prevent instability due to too much movement
What is clinically significant about transversospinalis?
They are stabilisers
When they are damaged, they rapidly atrophy and it is difficult to regain function.
Special physiotherapy is needed
What causes disk prolapse?
A tear in the outer annulus fibrosus, allowing the nucleus pulposus to bulge out
In which direction do tears normally occur?
Why?
They bulge out postero-lateral
This is due to the posterior longditudinal ligament in the vertebral canal
Are disk prolapses painful?
Bulge: not necessarily; only if the bulge reaches the outer third where there is nervous innervation
Herniation & Extrusion: yes, as the outer third of the intervertebral disk has nervous sensation
Describes what happens to intervertebral disks over the course of one’s life
The amount of fluid slowly decreases and the disks get thinner and the Articular cartilage degenerates
The bones start to rub against each outer –> painful
The body compensates and tries to limit movement of the joints.
Osteophytes grow to limit movement
What can growth of osteophytes sometimes lead to?
Encroachment on nerves in the intervertebral foramen or in the spinal canal
What is at risk in disk prolapse?
Why?
The nerve roots in the foramen
Posterior lonitudinal ligament protect the spinal cord itself
Where are disk prolapses common?
At the border of the lumbar and sacral regions
What is a compression fracture and in whom is it common?
It is a collapse of a vertebra due to trauma or weakening of the vertebra
It is common in the elderly
Why is rubbing bone of the vertebrae painful?
Sensory nerve supply in the bone
What is the role of the posterior longitudinal ligament?
Prevents hyperflexion of the vertebral column
Describe the joints in the vertebral column
Plane joints connect the Articular projections
Compare the joints in the thoracic and lumbar spine
Thoracic: guide rotation
Lumbar: guide flexion / extension
Does twisting movement of the spine cause injury?
It may cause injury
Because only 50% of annular fibres are positioned to resist load
What links the two latissimus muscles?
An aponeurosis
What are the tree levels of disc prolapse?
Bulge
Herniation
Extrusion
Why do osteophytes grow?
In an attempt to limit movement of the joint
Describe venous drainage of vertebrae
Basivertebral veins
Come out of the posterior aspect of vertebra
Where does the posterior longitudinal ligament expand?
Over IV disc
Describe what happens when weight is put through the spine
- Weight bearing forces
- Bulge of disc; incompressible, so it bulges out
- Annular fibres hold it all together; resist load
What is the general role of annulus fibrosus when weight bearing?
Resist load
