DI II Midterm Flashcards
What is occipitalization? How does it relate with basilar invagination/impression?
Occipitalization is the non-segmentation (or separation) of C1 and the occiput. Fusion would help you differentiate congenital versus acquired. Would appear as no space b/t occiput and C1 on xray (looks like C1 missing). Occcipitalization may exist in isolation or occur with basilar invagination and usually the encroachment (>8mm) of the odontoid into the foramen magnum (measured by McGregor’s line). Basilar invagination occurs when the top of the C2 vertebrae migrates upward. It can cause the opening in the skull where the spinal cord passes through to the brain (the foramen magnum) to narrow cause HA, nystagmus, muscle wasting
Where do you find a posterior ponticle?
C1 - partial or complete ossification of oblique portion of atlanto occipital membrane - contains vertebral artery and CN1
Arcuate foramen is usually not ossified
The condition may compress and traction the vertebral artery during neck manipulation.
present in 10-15% of population
What is the significance of George’s line?
George’s line describes the line drawn along posterior surfaces of the vertebral bodies on lateral views. The line should make a smooth curve form C1 to C7 (also used in thoracic and lumbar). Disruption indicates a segmental anterolisthesis (L5 common) or retrolisthesis of one segment on another. Other key landmarks to look at are the superior and inferior corners.
Why is an os odontoideum clinically significant?
The odontoid has broken off the body of C2 and it can be very dangerous to do a cervical adjustment. The joint is unstable (C1 can move independently of C2) and may be held together only by the transverse ligament. Often this anomaly is due to a childhood injury.
What are the radiographic differences between congenital block vertebra and acquired fusion of the spine (surgical)?
CONGENITAL BLOCK VEREBRA - non segmentation of 2 adjacent segments resulting in:
- decreased AP diameter
- rudimentary disk (small disk space)
- apophyseal joint fusion (posterior arch fusion)
- fusion of the SP (“wasp waisted”)
- often leads to DJD at adjacent joints (i.e if C3-4 are blocked…C2 and C5 have issues). More likely to occur in cervical.
ACQUIRED FUSION - surgical removal of the disc and two adjacent vertebra are fused together
- no disc seen on xray
- more common in the lumbar spine.
Klippel – Feil is a congenital fusion where no discs are seen.
What is the significance of the spinolaminar junction and spina bifida occulta in the lateral view?
Spina bifida oculta results in failure of fusion of the two posterior arch ossification centers producing a midline defect
- Because the lamina fail to fuse, this generally appears as a cleft SP on AP view.
- spinolaminar junction is often not visible on lateral view
What is a limbus vertebra? What is a schmorl’s node? Why is it common to see disc space narrowing adjacent to these findings?
schmorls nodes - herniation of nucleus pulposus through vertebral endplate due to developmentally weak endplate, trauma, or pathological process
- may be painful or asymptomatic - lateral radiograph shows focal indentation into vertebral body with sclerotic margin
limbus bone - (usually anterior) chipped vertebra, usually due to trauma
- nucleus makes its way into space also resulting in disc space narrowing
- usually asx, but may be source of future sxs
- posterior limbus bone is more problematic but rare
Where are cervical ribs most common? How can you tell whether a rib at the is a cervical rib or first rib?
Most common at C7 (also C6, C5)
Look at TPs on xray
- TPs of thoracic ribs go up while TPs of cervical ribs go down
What is a transitional lumbosacral vertebra?
Undifferentiated L5/S1
- L5 is fused to the sacrum, or appears “sacrum like”
- TPs may be “spatulated” (tall, unilaterally or bilaterally)
- L5 disc is hypoplastic
- DJD is common
What dysplasia may result in tall stature with hypermobile joints? What complications may be associated with this condition?
Marfans - autosomal dominant
- arachonodactyly
- dolichocephaly
- pectus excovatum
- undevelopment of muscles (fq dislocations)
- scoliosis
- dislocation of ocular lens
- congenital heart dz (ASD)
- aortic aneurysms
What is the most common cause of dwarfism? What neurologica condition may these individuals have that effects the legs?
Achondroplasia - autosomal dominant disturbance in epiphyseal chondroblastic growth/maturation
- common to have spinal canal stenosis leading to paraplegia of lower extremities
What is osteogenesis imperfecta? What clinical manifestations result?
Autosomal dominant disorder of connective tissue with widespread abnormalities, most seriously involving the skeleton, but also see changes in ligaments, skin, sclera, the inner ear, and dentition
- seen clinically as premature osteoporosis and ligamentous laxity which may be seen on xrays as radiolucency of bones
How can new fractures be distinguished from old fractures radiographically?
New fxs show jagged edges
Old fxs have more rounded edges and maybe the presence of callous formation (14 days post injury)
Compression fxs of spine show hemorrhage, hematoma, step defect, and zone of impaction ~ 2 months, then contiguous disc degeneration
Bone scan may present ‘hot spot’ for u to 2 yrs
What are the possible long bone fracture orientations?
Closed Fracture (Simple Fracture) Open Fracture (Compound Fracture) Complete Fracture (both cortices) Avulsion Fracture – muscle pulls off chunk of bone Incomplete Fracture (one cortex - peds) Growth Plate or Physeal Fracture (Salter-Harris) Stress Fracture (Fatigue & Insufficiency) Pathologic Fracture Dislocation Subluxation Fracture-Dislocation Bone Edema
What are the types of incomplete fractures of pediatric long bones and how do they differ?
TORUS - buckling of cortex
GREENSTICK - interruption of one cortex with angulation resembling a broken branch
BOWING - bending with no obvious cortical defect
What is a Salter Harris fracture? Which type is most common?
Growth plate fracture (in children)
Type I - fx longitudinally through plate
Type II - fx through plate and metaphysis - MOST COMMON
Type III - fx through plate and epiphysis
Type IV - fx through plate metaphysis, and epiphysis
Type V - compression of plate (stunts growth)
What is the difference between malunion and nonunion?
NONUNION - when the bone does not heal properly leaving the limb with pain and instability
MALUNION - when a fracture heals in a deformed position or with shortening of the limb
What is a jefferson fracture? What finiding is demonstrated in the APOM view?
Burst fracture of atlas - classically bilateral anterior and posterior arch fracture (‘lifesaver principle’) of C1 due to compressive blow on head - rarely causing neuro deficits due to widened spinal canal
APOM shows increased lateral paraodontoid space bilaterally and offset lateral masses of the atlas
What is traumatic spondylolistesis? Where does it usually occur in the spine?
“Hangman fracture” - bilateral pedicle fracture of C2 due to hyperextension in MVA
- usually no neuro finding, but maybe airway compromise or vertebral artery injury
- lateral c-spine shows anterior displacement of C2 with offset pedicle (CT for definitive dx)
What is a clay shoveler’s fracture? How is it differentiated from ununited secondary ossification center of SPs at cervicothoracic junction?
Clay Shoveler’s fx is avulsion of SP tup due to abrupt flexion or repeated stress from muscle pulls, most common at C7
- lateral view shows inferiorly displaced SP
- AP view shows double SP
- with ununited ossification center there is no displacement or jagged edges
What is the most common fracture of the spine? How do you differentiated new from old?
Compression Fracture - usually T12-L2 - due to axial compression/flexion force
- usually result in web shaped vertebra
- no neuro deficits
NEW compression fracture (< 2 mos) showshemorrhage, hematoma, step defect, and zone impaction
OLD compression fracture shows contiguous disc degeneration - bone scan may show hot spot for 2 yrs
What are the unstable fractures of the pelvis? What happens in each?
MALGAINE - unilateral SI fx/dislocation and ipsilateral superior pubic/ischiopubic rami fx due to verticle shearing force
BUCKET HANDLE - unilateral SI fx/dislocation and contralateral superior pubic/ischiopubic rami fx due to oblique force
STRADDLE - communuted fx of pubic arches - bilateral double verticle fx of superior pubic rami and ischiopubic functions with central fragment displaced postero-superiorly
SPRUNG PELVIS - complete separation of symphysis and one or both SI joints (DIASTASIS)
What is the most common type of acetabular fracture?
Central acetabular fx (explosion fracture) splits ilium into superior and inferior halves
What is the most common hip fracture? What aged individuals does this usually occur in?
Subcapital fx - mainly among older osteoporotic individuals
- also associated with pagets, fibrous dysplasia, malignancy, osteomalacia, rickets, osteonecrosis (radiation tx)
What proximal femur fx happens only in adolescents?
Slipped capital femoral epiphysis (SCFE)
- occurs mainly 10-15 yr olds often times during rapid growth spurt
- femoral neck slips off femoral head (salter harris I)
- 20-30% bilaterally
- only 50% associated with trauma
- pain often referred to knee
Which direction does the patella most commonly dislocate?
Superiolaterally
What is a Jone’s fracture? What bone does it occur in?
AKA dancer’s fx - transverse fx of base of 5th MT
occurs with plantar flexion/inversion sprain
What injury is often associated with calcaneal fx?
calcaneous fx (mos frequent tarsal bone to fx) is associated with thoracolumbar final fracture (10%)
What are the different types/grades of AC joint sprain?
TYPE I - mild
- AC ligament is stretched with coracoclavicular ligament intact
- radiographically normal
TYPE II - moderate
- AC lig is torn and coracoclavicular lig is stretched
- widened joint space with slight elevation of clavicle possibly seen in xray
TYPE III - severe
- AC lig and coracoclabicular lif disrupted
- widened joint space with elevated distal clavicle above acromion
- may require sx
What is the radiographic difference between anterior and posterior glenohumeral dislocations? Which is most common?
ANTERIOR (most common) with humeral head settling in:
- subcoracoid (most common)
- subglenoid
- subclavicular
- intrathoracic
POSTERIOR (rare) shows humeral head fixed often at the same level, appearing identically in internal and external rotation
What is a Hill-Sachs/Hatet defect? What about a bankart lesion? What injury are they associated with?
Hill sachs defect - impacted fx of humeral head
Bankart lesions - inferior glenoid fx
Both are associated with anterior glenohumeral dislocations
Which part of the clavicle is most commonly fractured?
Middle 1/3 - from falling on outstretched hand
What is the significance of the elbow fat pad signs (anterior and posterior)?
clinical signs of an intraarticular fx of the elbow
- displacement of anterior and/or posterior fat pads from between fibrous and synovial layers of the humeral joint capsule
- become visible from intraarticular effusion and edema
- 90% of children’s elbow fxs have visible posterior fat pads (less frequently seen in adults; absence of sign doesn’t preclude fx)
- A posterior fat pad is always abnormal.
What structures are involved in the most common fractures of the elbow in children and adults?
Adults – radial head/neck fracture
Children – supracondylar fracture (humerus)
What are the most common wrist fractures seen in children? young adults? elderly?
CHILDREN - distal radius torus fracture
ADULTS (15-40) – scaphoids – 70% at waist, 20% at proximal pole, and 10% at distal pole
ELDERLY – Colles’ fracture (distal radius) involves ulnar styloid 60% of the time
What is the difference between a colles and smiths fracture at the wrist?
COLLES - distal radius fx 20-35mm proximal to joint surface with distal fragment angulated posteriorly, also involving ulnar styloid 60% of time (falling on extended wrist)
SMITH - aka reversed colles - distal radius fx with distal fragment angulated anteriorly (falling on flexed wrist)
Discuss the vascular supply of the scaphoid and its effect in avascular necrosis and healing of this structure after fracture.
The scaphoid has three anatomical areas: proximal pole, waist, and distal pole. There are only two sources of blood supply to the scaphoid, one to the waist and one to the distal pole. The proximal pole does not have its own bld supply therefore a fx at the proximal pole can lead to AVN (and does ~15% of the time) dt lack of blood supply and subsequent inability to heal. AVN can be dxed via x-ray bc it will show up whiter than the surrounding bone.
What is the most commonly dislocated carpal bone?
Lunate dislocates anteriorly due to hyperextension injuries (pie sign on PA view)
What is a barroom fracture? And boxers fracture?
BARROOM - transverse fx of 4th or 5th MC neck caused by roundhouse blow
BOXERS - transverse fx of 2nd or 3rd MC neck caused by stabbing blow
What is gamekeepter’s thumb?
aka Skiiers thumb
- first MCP tear or rupture of ulnar collateral lig due to hyperabduction of thumb
What are the most common sites of stress fractures?
Metatarsals – “march fracture” or “deutchlander’s disease” Proximal tibia Calcaneus Distal fibula Hook of the hamate Dstal third of clavicle L5 pars inerarticularis
How can stress fractures be detected on plain xray? What imaging is most sensitive for detecting stress fracture?
delayed xray - 10-21 days post injury may show occult fracture
50% of stress fractures are never seen on xray finding
bone scans are sensitive but not specific
MRI will show bone edema and fracture earlier than CT (sensitive and specific)
What arer the most common types of spondylolistesis in the lumbar spine?
90% of all spondylolytic spondylolistheses involve the L5 segment.
Most degenerative spondylolistheses occur at L4.
What are the differences between spondylolytic spondylolisthesis and degenerative spondylolisthesis? (etiology and spinal level)
spondylolytic spondylolisthesis
- etiology: repetitive microtrauma, confenitally slender pars, acute fracture (rare)
- most common at L5 in young active individuals
degenerative spondylolisthesis
- etiology: disc space loss or loss of cartilage in facet joints
- most common at L4 in females over 40
What is the Meyerding’s grading system?
ratio of [overhanging part of the superior vertebral body] to [anteroposterior length of the adjacent inferior vertebral body]
The sacral base is divided into 4 equal sections.
Grade 1 - The posterior-inferior corner of L5 is aligned with the first division
Grade 2 - The posterior-inferior corner of L5 is aligned with the second division
Grade 3 - The posterior-inferior corner of L5 is aligned with the third division
Grade 4 - The posterior-inferior corner of L5 is aligned with the fourth division
Grade 5 - spondyloptosis (L5 anterior to S1)
What is an inverted/reversed Napoleon hat sign?
Napolean’s hat sign or bowline of brailsford shows significant anterolisthesis
