Di Imaging 2 Exam #1 Images

Depressed skull fracture

Blowout fracture

- fracture at floor of orbit

- MC due to direct trauma

- inferior rectus muscle may project into maxillary sinus

Tripod fracture

- Separation of all three major attachments of the zygoma to the rest of the face

Linear skull fracture

- most common type of skull fracture

Subdural hematoma

- blood gathers between the dura mater and the brain

- convex in shape

- venous involvement

Epidural hematoma

- blood gathers between the dura mater and the skull

- 15-20% are fatal

- concave (crescent) in shape

- arterial involvement

Posterior arch fracture

- MC fracture of atlas

- typically bilateral and vertical

- hyperextension mechanism

- differentiate from agenesis of posterior arch of atlas

Agenesis of posterior arch of C1 (with enlarged C2 spinous)

- differentiate from posterior arch fracture

- developmental anomaly

Jefferson's Fracture (Bursting fracture of C1)

- 2nd MC injury to atlas

- axial compression injury

- bilateral fracture of anterior and posterior arches

- overhang sign

- If the transverse atlantal ligament is torn, you'll see >7mm of offset

Type 1 odontoid fracture

- fracture of the tip of the dens

- avulsion of dens from alar or apical dental ligaments

- very rare

- stable and heals well

- differentiate from os terminale

Type 2 odontoid fracture

- MC fracture of dens

- unstable

- nonunion very common (64%)

- if displaced >5mm = 100% nonunion

Type 3 odontoid fracture

- fracture through body of C2

- unstable

- May disrupt Harris' ring

Hangman's fracture

- traumatic spondylolisthesis of C2

- 2nd MC fracture of C2

- bilateral pedicle fracture of C2

- hyperextension mechanism

- Send to ER

Compression fracture

- flexion mechanism

- Decreased anterior body height, preservation of posterior body height

- Superior endplates are affected

- stable

Burst fracture (of C3)

- vertebral body "explodes"

- possible cord compression

- unstable

- interpeduncular widening (seen on AP film)

Unilateral facet dislocation (of C4)

- flexion, rotation mechanism

- inferior articular process dislocates into the IVF

- anterior body displacement (25%)

- mechanically stable (relatively)

- decreased laminar length

- bow tie sign

- inverted hamburger sign on CT

Bilateral facet dislocation

- hyperflexion mechanism

- MC C4-C7

- severe soft tissue injury

- unstable, high incidence of cord injuries

- anterior displacement (typically >50%)

- Two types: (interlocking = complete, perched = incomplete)

Flexion tear trop fracture

- aka bursting tear trop fracture

- flexion mechanism

- most severe injury of cervical spine

- unstable (anterior cord syndrome)

- facets are "subluxated" or dislocated

- usually C4-C6

- triangular fragment at the anterior inferior vertebral body

Extension teardrop fracture

- aka avulsion fracture

- extension mechanism

- triangular fragment on anterior inferior vertebral body

- usually C2

- unstable

- buckling of ligamentum flavum

Clay shoveler's fracture

- aka root puller's fracture

- flexion mechanism

- C6-T1, (mc C7)

- avulsion fracture

- stable

- "double spinous sign" on AP film

Laminar fracture (of C6)

- uncommon

- mechanically stable

- hyperextension mechanism

- lower cervicals

- may need CT

Pillar fracture

- uncommon

- commonly missed on x-ray

- C4-C7

- extension/compression mechanism

- may need CT

Uncinate fracture

- rare

- stable

- lateral flexion mechanism

Whiplash

- hyperflexion/hyperextension mechanism

- soft tissue injury (flexion component)

-widened interspinous space (of C5/C6)

- subluxated widened facets

- disruption of posterior ligament complex

- flexion/extension views

Lumbar compression fracture of L1

- 90% occur between T11-L2

- MC fracture of thoracics and lumbars is compression

- flexion mechanism

- osteoporotic patients could have compression fractures with no trauma

- decreased anterior height

- posterior body height maintained

- may see step defect and zone of impaction (condensation)

Osteoporotic compression fractures

- More common in females >50 years old

- increased kyphosis (dowager's hump)

- accentuated vertical striations

- usually multiple levels

Pathological fracture

- decreased height of the entire body (implies pathology)

- Osteoporosis, Metastasis, or Multiple Myeloma

Vertebroplasty & Kyphoplasty

- minimally invasive procedures for treatment of compression fractures

- physicians inject a cement mixture into the fractured bone

- in kyphoplasty, a balloon is first inserted to create space

Green arrow

Burst fracture

- bursting "compression" fracture

- posterior body convexity

- retropulsion of the posterior fragments

- widened intrapedicular distance

- CT needed

Chance fracture

- "Lap belt" fracture

- flexion/distraction mechanism

- horizontal splitting of the arch and body

- MC L1-L3

- "Empty vertebra" sign

- commonly associated with compression fracture

Chance fracture (at L3)

- "Lap belt" fracture

- flexion/distraction mechanism

- horizontal splitting of the arch and body

- MC L1-L3

- "Empty vertebra" sign

- commonly associated with compression fracture

Transverse process fracture

- 2nd most common lumbar fracture

- MC L2-L3

- Vertical to oblique in orientation

- often unilateral and multiple levels

- often obscured by gas and fecal material

- potential renal damage (need urinalysis for potential hematuria)

Type 2 spondylolisthesis

- aka spondylolytic or isthmic

- stress fx, elongated pars, or acute fx

- biomechanical stress

- MC type for younger age

- MC at L5

Type 3 spondylolisthesis

- aka degenerative

- due to degeneration of posterior joint

- pars is intact

- MC at L4

- MC in females

- Older age onset

Type 4 spondylolisthesis

- aka traumatic

- acute one time trauma is rare

- MC type is a Hangman's fracture of C2

Spondylolisthesis (Radiographic)

- Inverted Napoleon hat

- Detected with George's line

- Graded by Meyerding's method

- May or may not have pars defects

Sacral fracture

- Direct trauma or fall on buttocks

- associated with other pelvic fractures

- most are horizontal near 3rd or 4th segments

- examine sacral foramen carefully

Duverney Fracture

- iliac wing fracture

- splitting of the iliac wing

- direct lateral force

- stable

Ischiopubic Rami Fracture

- MC STABLE fracture of the pelvis (40%)

- stable

- Inferior rami more common

- stress fracture may occur

ASIS avulsion fracture

- muscular traction of sartorius muscle leads to avulsion

- seen as curvilinear density

- may unite or remain ununited

- MC is ischial tuberosity avulsion

Ischial tuberosity avulsion fracture

- muscular traction of hamstrings leads to avulsion

- seen as curvilinear density

- may unite or remain ununited

- MC type of avulsion fracture

Malgaigne fracture

- ipsilateral double vertical shearing fracture of superior and inferior pubic rami with fx or dislocation about ipsilateral SI joint

- MC UNSTABLE pelvic fx (33%)

Bucket-Handle fracture

- contralateral double vertical fx

- superior and inferior pubic rami fx

- fx or dislocation about contralateral SI

- unstable

Straddle fracture

- bilateral superior and inferior rami fx

- substantial soft tissue injury

- unstable

Sprung pelvis

- "Open book" fracture

- diastasis of pubic symphysis

- diastasis of one or both SI joints

- unstable

Complex pelvic fracture

- unstable

- severe injury

- difficult to classify

- multiple fractures

- comminution of the pelvis