Thoracic and Lumbar Flashcards
What is the anatomy of the thoracic spine?
Thoracic spine has 12 nerve roots (T1 to T12) on each side of the spine
These branch from thespinal cord
Control motor and sensory signals mostly for the upper back, chest, andabdomen.
What are the characteristics of Vertebral bodies (VB), Vertebral Foramen (VF) Transverse processes (TVP), Spinous Processes (SP) and articular processes of the Thoracic spine?
VB - Heart shaped
VF - Round shape
TVP - Costal facets located to articulate with ribs
SP - Long, slant inferiorly
Articular processes - Demi-facets present on each side of vertebral body to articulate with ribs
What are the characteristics of Vertebral bodies (VB), Vertebral Foramen (VF) Transverse processes (TVP), Spinous Processes (SP) and articular processes of the Lumbar spine?
VB -Large and kidney-shaped. Deeper anteriorly than posteriorly
VF - Triangular in shape
TVP - Long and slender
SP - Short and broad
Articular processes - Nearly vertical facets
What are the clinical indications for the thoracic spine?
Fall from a height of > 3m
Ejection from a motor vehicle or motorcycle
Chronic conditions
Neurological deficit
Postoperative imaging
History of cancer and associated back pain
What are the routine projections for the thoracic spine?
AP Thoracic
Lateral Thoracic
What is the adequacy for an AP thoracic x-ray?
Adequacy
Should include C7 L1
SPs should be central = no rotation
Facet joints seen in profile
Best for visualizing compression fractures, subluxation or kyphosis
What is the adequacy of a lateral thoracic x-ray?
Adequacy
Should include T1 T12 at least
Facet joints and neural foramen are open,
Superimposition of spinous processes and posterior rib articulation
Upper Tx can be difficult to see (thick structures) – if concerned perform Swimmer’s View (see Cervical Lecture)
How is the patient positioned for lateral thoracic x-ray?
In a left lateral recumbent position, placing the heart closer to the image recepter minimizing overlap
What are the clinical indications for the lumbar spine?
fall from a height >3 m
ejection from a motor vehicle/cycle
acute back pain
neurological deficit
postoperative imaging
chronic conditions
history of cancer and associated back pain
What are the clinical indications for the sacroiliac joint?
Suspected fracture
SI joint dislocations orsubluxations
Inflammation (sacroiliitis) of sacrum &/or SI joints
What are routine projections for the Lumbar spine?
AP
Lateral
What are routine projections for the Sacroiliac joint?
AP/PA Sacrum
AP Oblique Sacrum
How would you position the patient for an AP lumbar x-ray?
TRAUMA = supine AP
NON-TRAUMA = Weight-bearing PA (Ferguson’s technique)
What is the adequacy for an AP Lumbar x-ray?
L1-L5 visible, including T/L junction and L/S junction
SPs central and iliac wings and SI joint appear symmetrical = no pt. rotation
Facet joints visualised
Should be able to clearly see lumbar VBs, pedicles, trabecular and cortical bone (adequate beam penetration)
How would you position patient for lateral lumbar x-ray?
TRAUMA - Supine
NON TRAUMA - Patient on their side
What is the adequacy for a Lateral Lumbar X-ray?
L1-L5 visible, including T/L junction and L/S junction
True lateral = superimposition of the greater sciatic notches,the superior articulating facets and the superior and inferior endplates
What are the additional projections of the lumbar spine?
AP and PA Lumbar Obliques
What is a Lumbar PA Oblique?
PA Oblique
Easier to position patient – can see the spine
RAO / LAO
(patient is facing the IR – x-ray travels P-A > the anterior aspect of the body/Lx is closest to the IR)
RAO and LAO will demonstrate the facet joints on the upside, for example, the LAO position will show the right facet joints
What is a Lumbar AP Olique?
AP Oblique
Harder to position patient – cannot see surface anatomical landmarks
Anatomy is closer to the image receptor = better image quality
RPO / LPO
(patient has their back against the IR – x-ray travels AP > the posterior aspect of the body/Lx is closet to the IR)
RPO and LPO will demonstrate the facet joints on the downside, for example, the RPO position will show the right facet joints
What are the features of the ‘scotty dog?’
Nose = Right TVP
Eye = Right pedicle
Ear = Superior articular process
Neck = Pars interarticularis
Leg = Inferior articular process
Jagged line under eye if visible = defect of spondylolisthesis
What radiograph assessments evaluate normal and abnormal skeletal relationships in the spine?
Lumbar Gravitational Line
Ullman’s Line
Intercristal/Tuffer’s Line
Lumbosacral Disc Angle
Interpedicular Distance
What is the Lumbar Gravitational Line?
Locate centre of the L3 body
Draw a line perpendicular to the bottom of the film.
This line should pass through the anterior 1/3 of the sacral base.
If the line falls anterior to the sacrum = anterior weight bearing (Hypolordosis).
If the line falls posterior to normal position = the lumbar spine has posterior weight bearing (Hyperlordosis).
Incorrect weight bearing can lead to premature degeneration of some lumbar vertebrae
What is Ullman’s line?
Construct the sacral base line (SBL) & draw a line 90° to it at the anterior margin of the sacral base
L5 should be on or behind this line.
If L5 is anterior to it/ line crosses body of L5 > anterolisthesis or spondylolisthesis at L5
What is Intercristal Line/Tuffier’s Line?
Line drawn across the superior aspect of both iliac crests
Normal = should pass through the lower half of the L4 vertebral body or the L4/L5 vertebral disc
Higher level: possible increased predisposition of L4/L5 to degenerative changes
Lower level: possible increased predisposition of L5/S1 to degenerative changes
What is the Lumbosacral Disc Angle?
Identify presence of disc herniation
2 lines are drawn:
1. Line parallel and through sacral base
2. Line parallel and through L5 inferior endplate
Acceptable range for measurement = 10-15°
An increase can also indicate a weight bearing shift posteriorly onto the facets, which can lead to additional wear and tear on these joints
What is the interpedicular distance?
Distance between the pedicles on frontal/coronal imaging
narrowed
widened
Useful for assessing spinal canal width > identifying stenosis
What is Congenital Block Vertebrae?
What is it?
“the fusion of thoracic vertebrae is less common and comparatively rare”
failure of separation of 2 or more adjacent vertebral bodies. Sacrum is a normal block vertebra
What causes them?
Congenital
How are they diagnosed?
X-ray : combined vertebrae may be of normal height, short, or tall. Partial/complete fusion of cortex and bony matrix is continuous.
Disc space is frequently absent or extremely small
Clinical significance:
Associations:
hemivertebra or absent vertebrae
Klippel-Feil Syndrome and can cause angulation of the spine
What is butterfly vertebra?
What is it?
The failure of fusion of the lateral halves of the vertebral body
What causes them?
Congenital
How are they diagnosed?
X-ray : 2 lateral wedge-shaped halves; mid-line sagittal cleft; widened interpedicular distance; larger pedicles; superior and inferior segments’ endplate change shape to accommodate the butterfly; scoliosis or kyphosis common
Clinical significance:
Associations:
anterior spina bifida +/-anterior meningocele
may be part of theAlagille syndrome
Jarcho-Levin syndrome
VACTERL association2
What is a hemivertebrae?
What is it?
Failure of ossification of one half of a vertebra
m/c = Lateral hemivertebra
Highest incidence = thoracic spine
What causes them?
Congenital
How are they diagnosed?
X-ray : wedge-shaped half vertebra
Clinical significance:
Common cause of scoliosis.
Vertebrae essentially acts as a wedge - causes curvature away from side where it is present
Associations:
Aicardi syndrome; cleidocranial dysostosis; gastroschisis; Gorlin syndrome; foetal pyelectasis; Jarcho-Levin syndrome; OEIS complex; VACTERL association; mucopolysaccharidosis
What are Schmorl’s nodes?
What is it?
Herniation of disc material into the vertebral body through adjacent endplate
What causes them?
Not fully understood – one thought is after spinal trauma
M > F
Not present in 1st decade of life
How are they diagnosed?
X-ray : Small nodular lucent lesions at the endplate of thoracic and lumbar vertebrae, may have a sclerotic margin
Best seen on CT or MRI
Clinical significance:
Should not be confused/misdiagnosed as Spondylodiscitis or Malignancy
What is nuclear impression?
What is it?
also known asnotochordal persistence
subtle, gradual inward defects of the endplates that tend to involve most of the endplate
What causes them?
Disputed
Lack of growth cartilage at site
Notochord regresses embryologically
How are they diagnosed?
X-ray : concave deformity in a lateral radiographic projection. cupid’s bowappearance: AP radiographic
Clinical significance:
Misdiagnosed for something sinister (?)
What is oppenheimer ossicle?
What is it?
Unilateral or bilateral
m/c single, unilateral ossicle of the inferior articular processes of the lumbar spine
can also occur at the superior articular process
What causes them?
non-union of a secondary ossification centre of the articular process
How are they diagnosed?
X-ray : circular and corticated osseous density in the location of the inferior articular process
Clinical significance:
Ddx: articular process fracture
What is spina bifida occulta?
What is it?
Malformation of one or more vertebrae
What causes them?
Congenital, arises during fetal development.
Mildest form of spina bifida, neural tube defect
How are they diagnosed?
X-ray : Usually an incidental finding on x-ray/MRI.
Structural malformation midline bony defect at the posterior arch.
Clinical significance:
Usually asymptomatic
Those with extensive SBO (more than one vertebrae);
foot deformity, leg weakness, numbness, clumsiness, bladder/bowel dysfunction, tethered cord
What is Spondylolithesis?
What is it?
the slippage of one vertebra relative to the one below.
What causes them?
Hereditary
congenital in children
can affect any one of any age
can be caused by rapid growth
those who play sports are more at risk if repetitively over stretching and straining lower back
How are they diagnosed?
X-ray : anterior displacement of a vertebral body on comparison to the VB directly below.
Clinical significance:
Graded and classification
Asymptomatic or symptomatic
What is Limbus bone?
Well corticated unfused secondary ossification centre, usually of the antero-superior vertebral body corner
What causes them?
secondary to herniation of thenucleus pulposusthrough thevertebral body endplatebeneath the ring apophysis
How are they diagnosed?
X-ray : Well corticated with a sclerotic margin; triangular shaped; Fragment will not fit gap on vertebrae like a fracture fragment would
Lateral view = best visualised
Clinical significance:
Generally asymptomatic and incidental finding
Misdiagnosed as a fracture (limbus or teardrop), degeneration or infection
What is Transitional vertebrae?
What is it?
A vertebra that has characteristics that are typical of the adjacent spinal segments.
What causes them?
Congenital
Clinical Significance
Usually asymptomatic
Can be associated with back pain.
Spinal arthritis, vertebral disc abnormalities & cord compression can be present in affectedvertebral levels
MOST COMMON = Lumbar transitional vertebra
Lumbarisation of S1: Assimilation of S1 to Lumbar spine, ~2% population, usually identified by presence of 6 rib free lumbar vertebrae
Sacralisation of L5: Assimilation of L5 to the Sacrum, more common than Lumbarisation, ~17% population, usually identified by 4 rib free lumbar vertebrae
What is Lumbarisation of S1?
Assimilation of S1 to Lumbar spine,
~2% population
usually identified by presence of 6 rib free lumbar vertebrae
What is Sacralisation of L5?
Assimilation of L5 to the Sacrum, m/c than Lumbarisation,
~17% population
usually identified by 4 rib free lumbar vertebrae
What is an abdominal aortic aneurysm?
What is it?
Focal dilation of the abdominal aorta measuring >3cm diameter
10th m/c cause of death in western world,
m/c in males, >65 years
What causes them?
Athersclerosis
High BP
Blood vessels diseases; infection in Aorta
Trauma
How are they diagnosed?
X-ray : Curvilinear calcification in paravertebral region on abdominal or lumbar films
Clinical significance:
CAN PRESENT AS LOW BACK PAIN!
Need to assess risk of rupture
Mortality HIGH from ruptured AAA
