Vertebral Column and Contents Practical Flashcards
What are some ‘red flags’ for backpain?
-
Cauda equina syndrome:
- Severe or progressive bilateral neurological deficit of the legs
- Recent-onset urinary retention and/or urinary incontinence
- Recent-onset faecal incontinence
- Perianal or perineal sensory loss (saddle anaesthesia or paraesthesia).
-
Spinal Fracture:
- Sudden onset of severe central spinal pain which is relieved by lying down.
- A history of major trauma minor trauma, or even just strenuous lifting in people with osteoporosis or those who use corticosteroids.
- Structural deformity of the spine
-
Cancer:
- Gradual onset of symptoms.
- Weight loss
How mayn cervical vertebrae do adults typically have?
7
How many cervical spinal nerves are there?
8 pairs of spinal nerves
How many thoracic vertebrae are there?
12
How many vertebrae are fused together to form the sacrum?
5
How many vertebae are fused together to form the coccyx?
4
The spinal cord typically ends at which vertebral level?
L1-L2
Below which vertebrae should you do a lumbar puncture?
Below L3
Where are the 2 lordosis’ located?
Cervical and lumbar regions
Where are the 2 kyphosis’ located?
Thoracic and sacral regions
Which region is each vertebrae taken from?
- Thoracic –> furthest left
- Cervical –> furthest right
- Bifid spinous process
- Foramina in the transverse processes
- Lumbar –> middle
- Thick, large vertebral body
- Short, stumpy spinous process
Label:
- A
- B
- C
- D
- E
- F
- A: vertebral body
- B: pedicle
- C: transverse process
- D: superior articular facet
- E: lamina
- F: spinous process
From left to right; cervical, thoracic and lumbar vertebrae
- Cervical:
- Smaller vertebrae –> more flexible
- Lumbar:
- Large vertebral body due to weight-bearing
Typical features of vertebrae?
- Vertebral body - lies anteriorly
- Vertebral arch behind the body
-
Vertebral foramen enclosed between body and arch
- Spinal canal which houses the cord/spinal nerves
-
Pedicles
- Connect the arch to the body
- Vertebral arch has many bony projections
- 2 transverse processes; posterolateral
-
Laminae
- These come together to form a single, midline posterior spinous process
-
Superior articular processes and facets
- For articulation with vertebrae above –> forms facet joints
- Inferior articular processes and facets
What is the pedicle of the vertebrae?
Two pedicles extend from the sides of the vertebral body to join the body to the arch –> a stub of bone that connects the lamina to the vertebral body to form the vertebral arch.
What is the lamina of the vertebrae?
The lamina of the vertebral arch are two broad plates, extending dorsally and medially from the pedicles, fusing to complete the roof of the vertebral arch. The 2 laminae come together to form the spinous process.
What is the superior and inferior articular processes and facets?
- A superior articular process extends or faces upward, and an inferior articular process faces or projects downward on each side of a vertebrae
- The paired superior articular processes of one vertebra join with the corresponding paired inferior articular processes from the vertebra above (via the facets)
What 7 processes arise from the vertebral arch?
- Each paired transverse process projects laterally and arises from the junction point between the pedicle and lamina.
- The single spinous process projects posteriorly at the midline of the back.
- A superior articular process extends or faces upward on each side of a vertebrae
- An inferior articular process faces or projects downward on each side of a vertebrae.
How do the cervical vertebrae differ?
- A small body
- Usually have a bifid spinous process
- The spinous processes of the C3–C6 vertebrae are short, but the spine of C7 is much longer.
- Prominent C7 spine located at the base of the neck
- The spinous processes of the C3–C6 vertebrae are short, but the spine of C7 is much longer.
- The transverse processes of the cervical vertebrae are sharply curved (U-shaped) to allow for passage of the cervical spinal nerves.
- Each transverse process also has an opening called the transverse foramen.
How do the thoracic vertebrae differ?
- 2 costal demi facets on either side of vertebral body for articulation with head of rib
- Superior costal facet articulates with head of rib above
- Inferior costal facet articulates with head of corresponding rib
- Presence of costal facets on the transverse process for articulation with the tubercles of the ribs
Compare the spinous process of:
- Cervical spine
- Thoracic spine
- Lumbar spine
- Cervical:
- Typically bifid
- Typically short except when you get to C6 and C7
- Projects out horizontally
- Thoracic:
- Typically long
- Projects out obliquely, meaning it overlaps the spinous process of the vertebra below
- Lumbar:
- Short but think
- Spinous process projects out horizontally
What is the vertebra prominens?
The name of the seventh cervical vertebra –> the long and prominent spinous process is palpable from the skin surface
How does the vertebral foramen vary between the:
- cervical spine?
- thoracic spine?
- lumbar spine?
- cervical:
- triangular shape
- relatively large vertebral foramen
- thoracic:
- rounded shape
- lumbar:
- triangular shape
- relatively small
What is benefit of relatively large vertebral foramen in cervical spine?
Gives spinal cord ‘wiggle room’ –> cervical injuries don’t always result in spinal cord damage
View of C1
- No vertebral body
- No spinous process
- Posterior arch is larger
- Anterior arch is shorter
- 2x lateral masses with articular surfaces both superiorly and inferiorly
- Superior facets articulates with occipital condyles
- Inferior facets articular with the superior facets of C2
View of C2
- Presence of dens (bony projection) –> this is an anterior structure as is a modification of the vertebral body
- Small spinous process (often bifid)
- Vertebral formamina in transverse process
How do the lateral masses of the cervical vertebrae articulate?
- Lateral masses have superior and inferior articular facets
- Should align
What are the lateral atlanto-axial joints? How many of them are there?
Formed by the articulation between the inferior facets of the lateral masses of C1 and the superior facets of the lateral masses of C2 –> there are 2 of these
What is the medial atlanto-axial joint? How many of them are there? What key structure supports this joint?
- Formed by the articulation of the dens of C2 with the articular facet on the anterior arch of C1.
- 1 of these
- Transverse ligament of the atlas
What movement does the medial atlanto-axial joint allow?
This allows for rotation of the head independently of the torso.
Why are injuries to the dens not always catastrophic?
Due to protective nature of the transverse ligament of the atlas –> problem comes if this ligament is ruptured and dens is then at risk of being driven into brainstem/cervical cord.
How does C1 articulate with the base of the skull? What joint is this?
Occipital condyles of the occipital bone articulate with the superior facet (of the lateral masses) of C1 (atlas).
This is the atlanto-occipital joint
What movement is permitted at the atlanto-occipital joint?
Flexion at the head i.e. nodding
What type of injuries can lead to ‘axial loading’?
- Direct blow to top of head e.g. diving into excessively shallow water
- Also called ‘Jefferson fracture of the atlas’
*
What mechanism of injury can occur during ‘axial loading’? Why is damage to the spinal cord unlikely at the C1 level?
- Blow can can compress the lateral masses of the atlas between the occipital condyles and the axis
- Causes them to be driven apart –> fracturing one or both anterior/posterior arches (due to ring structure)
- If the fall occurs with enough force, the transverse ligament of the atlas may also be ruptured.
- Since the vertebral foramen is large, it is unlikely that there will be damage to the spinal cord at the C1 level
When interpreting C-spine x-rays, what should you look for?
- Normal alignment of vertebral bodies and spinous processes
- Trace around all the vertebrae looking for signs of fracture (i.e. breaks in the cortex of a bone)
- Look for uniformity in the thickness of the spaces between vertebral bodies
What 3 views of the C-spine are typically taken during x-rays?
- Lateral
- AP
- Open-mouth peg view –> this view shows alignment of lateral masses of C1 and C2 as well as the dens/odontoid peg
What does the ‘open-mouth peg view’ allow us to see?
- The dens
- Normal alignment of C1 and C2 by checking that their lateral masses ‘line up’
- Joint spaces should be same thickness
Case 1
A 20-year-old man was thrown from his mountain bike and immediately afterwards had neck pain. He was C-spine immobolised and taken to the ED. He had no abnormal neurological signs on examination.
- What can we see on this open-mouth peg view x-ray?
- Why doesn’t he have any abnormal neuro signs?
- What should happen next?
- Dens fracture
- Transverse ligament of atlas is still intact, also extra space in vertebral canal
- Refer patient for further imaging, remains C-spine immobilised, surgery needed
Proximity of dens to lower part of brainstem
Case 2
An 82 year old lady presented to GP with worsening of her chronic back pain. She was having night pain and her regular analgesia was becoming ineffective.
- Can you identify vertebrae 1-5? Which landmark is helpful?
- What abnormal features can you identify on this lateral x-ray of the lower thoracic and lumbar spine?
- L5 is just above the sacrum
- Joint spaces different between each vertebrae –> sign of arthritis
- Osteophytes
- Calcified aorta
View of sacrum
How mant vertebrae form the sacrum?
Fusion of 5 vertebrae –> no intervertebral discs
How many segments of the coccyx are there?
4
What passes through the 4 anterior sacral foramina seen here?
Anterior rami of spinal nerves
What part of the sacrum is this?
Lateral masses
Where is the most inferior functional intervertebral disc found?
Between L5 and S1
This is the posterior sacral foramina. There are 4 pairs of these. What passes through here?
Posterior rami of spinal nerves
View of continuation of spinal canal into the sacrum
What ligament is being pointed to? Function?
- Anterior longitudinal ligament –> binds together the anterior surfaces of the vertebrae and discs
- Limits extension
What ligament of the spinal cord can be injured in hyperextension injuries?
Anterior longitudinal ligament
Location of posterior intervertebral ligament? Function?
- Binds together the posterior aspect of vertebral bodies and intervertebral discs
- Lies inside vertebral canal
- Prevents herniation of the intervertebral discs into the vertebral canal
- Also limits excessive flexion
View of the cauda equina
What are intervertebral discs composed of?
- An outer annulus fibrosus
- A nucleus pulposus (gelatinous structure)
How does the nucleus pulposus change with age?
- Dehydrates with age –> puts more strain on outer fibrous part
- Can start to develop fissures and even tear
- Inner part can prolapse backwards and impinge on spinal nerves –> slipped disc
What can the prolapse of the nucleus pulposus result in?
- if it prolapses posterolaterally –> can compress spinal nerve
- if it prolapses directly posteriorly –> can compress spinal cord/cauda equina itself
Clinical Case
40 year old man presented to the emergency department with a five day history of lower back pain, numbness down his left leg and saddle and perineal anaesthesia.
- Why was an MRI chosen to investigate the symptoms?
- What is causing the patient’s symptoms? At which level is pathology?
- What should happen next?
- MRI allows you to see soft tissues (CT doesn’t)
- Worried about compression of cauda equina
- MRI allows you to see intervertebral disc, cauda equina, CSF
- Slipped disc between L5 and S1 compressing cauda equina and dural sac
- Surgical emergency
Where does the dorsal and ventral root join to form the spinal nerve?
At the level of the intervertebral foramen
View of the dural sac
View of a spinal nerve
Which meningeal layers do the spinal nerves take with them as they exit the canal?
Dura and arachnoid mater
View of spinal cord (dura been reflected)
What is this?
Conus medullaris –> tapered end of spinal cord
What extends from the conus medullaris? Function?
- Filum terminale
- This is a pial thread (extension of pia mater) that secures the spinal cord inferiorly to the coccyx
What is this collection of long nerve roots (lumbar and sacral) called?
Cauda equina
In which region is the cauda equina found?
Lumbar cistern
What is the lumbar cistern?
An expansion of the subarachnoid space, filled with CSF
What is this expanded region?
Dorsal root ganglion
What are denticulate ligaments?
- Lateral extensions of pia mater that secure the cord on either side –> anchor to the dura mater
- These are interspersed between spinal nerves
What is being pointed to?
Vertebral arteries (in cross-section)
Symptoms of cauda equina syndrome?
- Severe low back pain
- Motor weakness, sensory loss, or pain in one, or more commonly both legs
- Saddle anesthesia (unable to feel anything in the body areas that sit on a saddle)
- Recent onset of bladder dysfunction (such as urinary retention or incontinence)
- Recent onset of bowel incontinence
- Sensory abnormalities in the bladder or rectum
- Recent onset of sexual dysfunction
- A loss of reflexes in the extremities
