DI 2- Midterm Flashcards
• What is the relation between occipitalization and basilar invagination?
o Occipitalization: non-segmentation of C1 and occiput, no space bw on xray (looks like C1 missing). Fusion is congenital, vs acquired. may exist in isolation or w basilar invagination, usu w odontoid encroachment (>8mm) into foramen magnum (measured by McGregor’s line)
o Basilar invagination: tip of odontoid (C2) projects thru foramen magnum, narrowing it; may compress brainstem
• Where is posterior ponticle? What is it?
o Common variant on C1. contains vertebral artery, C1 nerve.
o may compress and traction vertebral a during neck manipulation
• What is the significance of George’s line?
o = line drawn along posterior surfaces of vertebral bodies on lateral views. should be smooth curve from C1 to C7 (also used in T & L).
o Disruption indicates segmental anterolisthesis (L5 common) or retrolisthesis of one segment on another.
o Other key landmarks: superior and inferior corners.
• What are anterolisthesis and retrolisthesis?
o A: anterior degenerative spondylolisthesis (forward displacement)
o R: posterior d.s. (backward displacement)
o spondylolisthesis= displacement of vertebrae, esp L5, commonly after fracture
• Why is an os odontoideum clinically significant?
o odontoid broken off C2 body, mb very dangerous to do cervical adjustment.
o jt unstable (C1 can move independently of C2), mb held together only by transverse ligament.
o Often dt childhood injury.
• What are the radiographic differences between an anomalous block vertebra and an acquired fusion of the spine?
o Block vertebra: non segmentation → ↓ AP diameter, rudimentary disk (small disk space), apophyseal joint fusion (posterior arch fusion), fusion of SPs. Called “wasp waisted” appearance. → DJD at adjacent joints (ie if C3-4 are blocked…C2 and C5 have issues). More likely in cervical.
o acquired fusion (surgical): disc removed, two adjacent vertebra fused (no disc seen on xray). more common in lumbar. Congenital fusion is Klippel-Feil (also no disks)
• What is the significance of the spinolaminar junction and spina bifida oculta in the lateral view?
o Spina bifida oculta → failure of fusion of two posterior arch ossification centers →midline defect
o lamina fail to fuse → cleft SP on AP view
o spinolaminar junction often not visible on lateral view
• Why is it common to see disc space narrowing adjacent to a limbus vertebra and/or Schmorl’s node?
o Dt intra body herniation of disk material. nucleus pulposus herniates thru vertebral endplate. usu dt trauma, or weak endplate, pathologic process (osteoporosis). Pain usu asx.
o lateral radiograph: focal indentation into vertebral body w sclerotic margin (look like chips of the endplates). herniation thru ring apophysis (2nd growth center)
o Assoc disc usu narrowed
• How can you tell whether a rib at the cervicothoracic junction is a cervical rib or first rib? Sxs?
o orientation of TPs. up= thoracic. down= cervical
o Cervical ribs usu only at C7 (also C6,C5). only 2/3 are BL. may fuse to 1st rib.
o Sxs: TOS, drooping shoulders, ↑ thoracic kyphosis.
o Don’t confuse w hyperplastic TP (articulation w TP differentiates)
What is a transitional lumbosacral vertebra?
o undifferentiated L5 or S1 (or partially fused)
o TP is spatulated (>19 mm vertically) uni or BL
o May form accessory jts w sacral alae or fused to sacrum
o L/S disc hypoplastic.
o Degeneration often present
• Name a dysplasia that may present with tall stature and hypermobile joints?
o MARFAN’S SYNDROME
o = CT dz w abnormal collagen formation
• What complications may be associated with this Marfan Syndrome?
o long, slender tubular bones
o ocular abnormalities (myopia), aortic aneurysm, pectus excavatum
o Underdeveloped, hypotonicity of muscles → jt laxity, dislocation
o Hip dislocation, genu recurvatum (knee bends backward), patellar dislocation, pes planus (flat feet)
What is the most common cause of dwarfism? Neuro condition these individuals may have that affects the legs?
o ACHONDROPLASIA: bone growth do, 70% dwarfism
o Infant: small foramen magnum and hydrocephalus → cord compression
o Adult: congenital spinal stenosis → paraplegia
• Fragile osteopenic bones are associated with which dysplasia?
o OSTEOGENESIS IMPERFECTA
o =Osteoporosis w abnormal fragile skeleton, blue sclerae, mb abnormal dentition
• What are the radiographic findings of new vs. old fractures? Healing?
o New: “Step defect” (rounds over with time), “zone of impaction” (for a couple months); mb jagged edges, no new opacity around edges, indications of soft tissue damage
o Old: osteophytes (from increased DJD), anterior wedge deformity; corticated edges
o healing fracture: enlarged edges of increased opacity show up about 14-days post-fracture
• What are the possible long bone fracture orientations? Head of long bone?
o transverse, oblique, spiral, comminuted (web of hairline fxs), segmented, avulsion (tendon pops off w some bone, like condyle), torus, greenstick, impacted, laterally or medially displaced, laterally or medially angulated o Transcervical (across neck) o Intertrochanteric (between G and L trochanter, under neck) o Subcapital (right below head) o *Subtrochanteric o *Greater/lesser trochanter fracture
• What are the types of incomplete fractures of pediatric long bones and how do they differ?
o Torus: buckling of cortex, looks like BL bulge
o Greenstick fractures: incomplete fracture; one side of bone is broken (cortex), other is bent.
o Bowing: bending w/o obvious cortical defect
o Growth plate fractures: specific locations dt ↑ growth in childhood
o [Dislocated “slipped” epiphysis of femoral head (only older,10-17)]
• Which is the most common type of Salter Harris fracture? Most serious? Others?
o =TYPE II fracture: thru growth plate and metaphysis
o Type I: thru growth plate no bone involvement
o Type III: gp + epiphysis
o Type IV: metaphysic + gp + epiphysis
o Type V: compression of gp (compare w non-invovled side to dx)= most serious
• What is the difference between a malunion and a nonunion fracture?
o Nonunion: absence of healing (no fusion), after several months
o Malunion: healing w incorrect anatomical alignment (incorrect fusion), causes impairment
• What significant finding is demonstrated in the APOM (open mouth) view with a Jefferson’s fracture? Best projection to see the most common fracture?
o jefferson=burst fracture of atlas (like a life saver candy: usu breaks into many pieces rather than just a chip off side). at least one fracture in anterior arch and one thru posterior arch; dt compressive force to head on apex
o APOM: increased lateral paraodontoid space BL. lateral masses of C1 that have slid laterally (>3mm). usu swelling. Ex: lateral offset of C1 on C2 bilaterally
o posterior arch fx, seen in lateral
• What is traumatic spondylolisthesis and what cervical level does it usually occur at? seriousness? definitive imaging? radiographic findings (projection)?
o Aka Hangman’s fracture. Usu at C2
o =bilateral pedicle (pars) fracture, often dt MVA
o surgical attention
o CT
o increased retropharyngeal space, C2 anterior on C3, fracture lines ant to inferior facet (lateral)
• What are the key radiographic differences between an un-united secondary ossification center of the spinous process at the cervicothoracic junction and a clay shoveler’s fracture?
Is clay stable or not?
o Un-united: Fracture displaced caudally with jagged edges (2’ growth centers usually don’t get displaced and will be more posterior rather than inferior)
o clay shoveler’s fracture (most common at C7): Lateral view shows inferiorly displaced SP. AP view shows “double spinous process” sign (looks like 2 SP’s on a single vertebrae)
o stable
