Lecture 8- The spine Flashcards
what is the vertebra bone classification?
Irregular bones
spine divided into 5 groups, and how many vertebrae in each?
- cervical- 7 vertebrae
- thoracic- 12 vertebrae
- lubar- 5 vertebrae
- sacral- 5 fused vertebrae
- coccyx- 4 fused vertebrae
how mnay vertebrar
what structures does a typical vertebra consist of?
-body (anterior part)
-vertebral arch (posterior part)
what is the body of the vertbra
cylindrical in shape. Anterior aspect convex, posterior aspect concaved. Superior and inferior aspects are flat.
what seven processes does the vertebral arch consist of?
- pedicles (paired)
- Laminae
- Spinous process
- Transverse process
- Articular process
- Pars inter articularis
- Intervertebral foramina.
The vertebral foramen is enclosed between the body and the vertebral arch. (Contains the spinal cord)
what are spinal features of the cervial spine 3-6
**body- **Small, Wide side to side, Lateral margins on thesuperior aspect of the bodyhave raised sides (uncinatedprocess)
**spinous process- **short, bifid, projects directly posterior.
vertebral foramina-traingular
transverse process- contains transverse foramina
superior articularing process- superoposteriorly
inferior articulating process- inferoanteriorly.
what are spinal features of the thoracic spine
**body- ** Larger than cervical
Heart shaped
Bears two costal demi-facets
**spinous process- **long, charp, projects inferiorly
vertebral foramina-circular
transverse process- Bears facets for ribs (except 11 and 12)
superior articularing process- posteriorly
inferior articulating process- anteriorly.
spinal features of lumbar spine
**body- ** Large
Kidney shaped
Deeper anterior than posterior
**spinous process- ** short, blunt, projects posteriorly
vertebral foramina-triangular
transverse process- No special feature
superior articularing process- posteromedially
inferior articulating process- anterolaterally
spine mechanisms of injury
RTA’s 45%
Falls 20%
Recreation/Sport 15%
Intentional Violence 15%
Other 5%
Male dominance M:F = 4:1
what are some of the sytpical vertebrae of the c spine
- ATLAS- first cervical vertebra
- AXIS- second cervical vertebra
- SEVENTH cervical vertebra
what does Atlas - First cervical vertebra
Consists of ?
Anterior arch – contains anterior tubercle
Posterior arch– contains posterior tubercle
Two lateral masses
Larger transverse process
No body
what is the main featire of AXIS the second cervical vertebrae
-odontoid process
features of seventh vcervical vertebra
Seventh cervical vertebra
Consists of a prominent spinous process that is not bifid
Transverse process large
C spine fracture prevalence
Fractures of C5/C6
are most common. This is because most injuries are due to hyperflexion, with the maximum force being focused upon the vertebral bodies of C4-C7.
In children under 8 years
fractures are infrequent. If they do occur, they are likely to involve C1/C2.
Injuries of the cervical spine produce neurological damage in approximately 40% of cases. Due to burst fractures or facet joint dislocations
importance of lateral radiographs with c spine x rays
The majority of detectable abnormalities will be visible on the lateral radiograph.
anatomical lines should be traced:
anterior vertebral body cortex
posterior vertebral body cortex
spinolaminar junction
Posterior Spinal Line
c spine lateral radiograph soft tissue
Soft tissue
An increase in the retropharangeal soft tissues may be caused by haemorrhage or oedema
C1 - C4 = 4-7mm (should “hug” the anterior cortex)
C5 - C7 = 16-20mm (roughly equal to vertebral body)
what is assessed when doing a c spine ap projection
The AP radiograph is often overlooked, however, some fractures that are not visible on the lateral radiograph will be visible on the AP.
Assess:
Superior and inferior endplates
Spinous processes
Lateral masses
PEG VIEW
Open Mouth Radiograph (C1/C2)
This view enables assessment of C1 and C2 (fractures of the odontoid peg.
Often more visible on thelateral projectiondue to subsequent anterior / posterior displacement.
Lateral masses of C1 should not overhang the lateral masses of C2. If present, this is indicative of a burst fracture:
There should be symmetric space between the odontoid peg and lateral masses of C1.
However, beware that normal asymmetric widening may be seen due to rotation of the patient’s head.
neural arch fracture
c
cervical
Longitudinal fracture through the posterior neural arch, usually bilateral.
It is caused by hyperextension, with the result that the neural arch of C1 is compressed between the occiput and C2.
It is best demonstrated on the lateral projection.
c1- ring structure most likely will have more than one fracture often due to hyperextension
Burst (Jefferson) fracture
c
Comminuted fracture, with bilateral disruption of both anterior and posterior arches, and lateral displacement of both lateral masses.
It is caused by axial compression with the transmission of force from the skull downwards through the occipital condyles, compressing the lateral masses.
Demonstrated on the open mouth view by:
unilateral C1/C2 odontoid peg joint space widening.
lateral masses of C1 overhang the lateral masses of C2.
Axis (C2) Odontoid peg fracture
c
This is the most common fracture of C2
Caused by flexion or extension and usually results in ligamentous instability.
Usually involves the base of the peg.
Can be visualised on either the open mouth or, more commonly, lateral view.
Assess for any soft tissue swelling anteriorly. Also look carefully at Harris’ ring on the lateral projection.
Anterior wedge compression fracture
c
Caused by hyperflexion
The vertical height of the vertebral body is decreased anteriorly
Visible on lateral radiograph
The posterior elements remain intact. This is a stable injury.
Burst fracture
c
Caused by axial compression
The intervertebral disc is driven into the vertebral body below.
The vertebral body explodes into several fragments
A fragment from the postero-superior surface being driven posteriorly into the spinal canal.
This is an unstable injury that frequently results in spinal cord injury.
It is therefore important to check the posterior vertebral cortex for evidence of disruption
Bilateral locked facets
cervical
If the amount of distraction increases, the facets may become disarticulated.
The vertebral body is displaced anteriorly by 50%
the inferior facets of the anteriorly displaced vertebra lie anterior to the superior facets of the vertebra below.
Assess both anterior and posterior vertebral lines.
look carefully at the facet joints; they should have a “roof tile” appearance, parallel to one another.
teardrop extension fracture
cervical
Hyperextension causes a triangular fragment to be avulsed off the antero-inferior corner of the vertebral body.
This is not associated with any neurological damage.
The axis is most commonly involved.
spinous process fracture
c
Avulsion by the supraspinatous ligament off the spinous process
Usually C6 or C7
Caused by flexion as the body rotates relative to the head and neck.
Usually undisplaced and therefore only seen on the lateral radiograph
spondylosis
c
Refers to degenerative changes of the intervertebral disc spaces, which is demonstrated by disc space narrowing, endplate sclerosis and osteophyte formation.
Facet joint OA is seen posteriorly. The associated osteophytes may impinge on the nerve root foramina.
The appearance of significant degenerative changes within the cervical spine may obscure underlying injury. It is therefore important to search for co-existant trauma.
A common mechanism of injury in those patients with spondylosis (often the elderly) is a fall directly onto the forehead with a subsequent fracture at C2
metastatic disease
Primary tumours can metastasise to the vertebral bodies demonstrating a lucent, moth-eaten, permeative appearance.
There is often subsequent collapse.
what needs to be assessed on an AP, LAT t and l spine x rays
Height of vertebral bodies should be equal.
Width of intervertebral disc spaces should be uniform.
Continuity of superior and inferior endplates: should remain unbroken.
Distance between spinous process should be equal.
Trace the posterior elements; the pedicles, laminae, and spinous processes.
what three columns is the spine split into for thr ourpose of assessment of stability?
Anterior column - Involves the anterior two thirds of the vertebral body/intervertebral disc, and the anterior longitudinal ligament.
Middle column - Involves the posterior aspect of the vertebral body/intervertebral disc, and the posterior longitudinal ligament.
Posterior column - Involves the posterior elements - the lamina, facet joints, spinous processes, and the associated ligaments.
wedge compression fracture
t/l
Forward flexion causes wedge compression deformity of the anterior vertebral body
the normal posterior concavity of the vertebral body remaining intact.
Often occurs in association with fracture to the superior endplate.
Chance fracture
May occur with use of seat belt during a deceleration injury.
Refers to compression fracture of the vertebral body with transverse/horizontal fractures of the posterior elements
With an increase in distraction, the AP will demonstrate an “empty” vertebral body, as the posterior elements will not be superimposed on the vertebral body.
There will be an increase in the inter-spinous distance and a break in continuity of the pedicles or spinous process.
Lateral will show an increase in the inter-spinous distance with horizontal fractures of the spinous process/lamina/pedicles running into the vertebral endplates.
fracture dislocation
l/t
The anterior and posterior vertebral lines will demonstrate malalignment, with disruption of the facets posteriorly.
Occurs in association with anterior wedging of the vertebral body below, with a characteristic triangular fragment arising from the antero-superior margin.
Lateral dislocations are also seen. High probability of neurological deficit
spondylosis
l/t
Refers to degenerative changes of the intervertebral disc spaces, which is demonstrated by disc space narrowing, endplate sclerosis and osteophyte formation.
Facet joint OA is seen posteriorly. The associated osteophytes may impinge on the nerve root foramina.
pagets disease
l/t
Paget’s disease
The lumbar spine is often affected. There are three key features:
Bone is expanded
The cortex is thickened
The trabeculae is coarse
metastatic disease
l/t
Primary tumours may metastasize to the vertebral bodies
Either demonstrate a “moth-eaten“ or sclerotic appearance.
ankylosing spondylitis
l/t
Refers to calcification of the anterior and posterior longitudinal ligaments
Colcification of intervertebral discs resulting in fusion of the spine from the sacroiliac joints up through the thoracolumbar spine to the cervical spine.
“Bamboo spine”
Increases a patient chance of fracture.
