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
- What is the most common fracture of the spine?
- Location?
- how do you differentiate new from old?
- stable or not?
- radiologic findings?
- COMPRESSION FRACTURE
- Usu at T12-L2
- New ( < 2 mos): Hemorrhage, hematoma, step defect (sharp ant step-off/overhang of superior corner), zone of impaction/condensation (horizontal white line paralleling superior endplate), paraspinal mass
o Old: adjacent DJD
o Bone scans may show “hot spots” for up to 24 months - stable
- ant wedge deformity (> 15%), step defect, zone of condensation, disruption of endplate, paraspinal edema, abdominal ileus
• List and describe the unstable fractures of the pelvis.
o Unstable: may move during healing → neurologic damage. Pelvis: may cause significant organ or vascular damage
o Fx of both ant. and post arches. 33% of pelvic fx. Usu dt significant trauma (MVA).
o Malgaigne (MC, unilateral, 14% of all pelvic fx)
o bucket handle fx: vertical, thru superior and inferior pubic rami on one side w contralateral SIJ disruption/dislocation
• what are stable fractures of the pelvis?
o Doesn’t move during healing, no threat to the spinal cord/cauda equina. Pelvis: no threat to organs or vasculature
o Fx w/ a single break in ring! Usu dt moderate fall, etc. 66% of pelvic fx
• What is the most common type of acetabular fracture?
o Central Acetabular Fracture (aka Explosion Fracture)
• What is the most common hip (proximal femur fracture) and what age do these often happen in?
o Subcapital Fracture. Often missed. Elderly. F>M 2x
• Name and describe the proximal femur fracture that happens only in adolescents.
o Slipped Capital Femoral Epiphysis
o Usu 10-15 yo, during rapid adolescent growth period
o femoral neck slips up off femoral head
o Actually a fracture (Salter-Harris Type I, at growth plate only)
o 20-30% occur BL (BL F>M, but overall M>F)
o If BL, 2nd slip within 1 yr
o Only 50% have hx trauma
o Assoc: Renal osteodystrophy, rickets, radiation therapy
• Which direction does the patella usually dislocate?
o superolateral dislocation
o may also move horizontally or vertically
• What is a Jones’ fracture and what bone does it occur in?
o Most common foot injury. Dancer’s fracture.
o transverse fracture of base of 5th MT
• Name an associated injury that must be evaluated for when a patient presents with a calcaneal compression fracture.
o 10% assoc w thoracolumbar spinal fxs; must r/o either compression or burst
o Calcaneus is most frequently fx tarsal bone- fx line often cannot be visualized, so need Boehler’s angle. < 28 deg = compression fx
• What are the area referred to in AC jt sprains?
o AC jt space: Should be BL and symmetrical, within 2-3 mm of each other, and avg 2-4 mm wide
o AC alignement: Inferior margins of clavicle and opposing acromion should be smooth and horizontal
o Coracoclavicular distance: Normal11-13mm (bw inferior margin of clavicle and closest surface of coracoid). 5mm max difference bw R & L
• What are the different types/grades of acromioclavicular joint sprain?
o Type I and II managed conservatively, Type III requires jt repair and open fixation
o Type I: Mild Sprain, AC lig stretched, CC lig intact; wt bearing doesn’t ↑jt space or alter alignment; normal radiograph
o Type II: Moderate Sprain; AC lig torn, CC lig stretched, widened jt space, slight elevation of clavicle possible
o Type III: Severe Sprain, AC & CC ligs disrupted, widened jt space; elevation of distal clavicle above acromion; CC space > 5mm than contralateral side
• What is the radiographic difference in anterior vs. posterior glenohumeral dislocations? Which is most common?
o ~95% GH dislocations are anterior
o Anterior: Humeral head may settle in: subcoracoid (most common, Inferior and medial displacement), subglenoid (Altered humeral head shape), subclavicular (Hill-Sachs defect), intrathoracic (Bankart lesions: inferior glenoid fx)
o Posterior: Humeral head looks identical in IR & EI, bc fixed in its posteriorly displaced position. Humeral head often stays at same level as glenoid or superior to it. Dt epileptic convulsions, electric shocks, direct trauma (ie huge muscle spasm/force pulls it posteriorly)
• What are Hill-Sachs/Hatchet and Bankart lesions and what are they associated with?
o Hill: impaction fx of superior posterolateral humeral head (Best seen on AP w IR, better on MR). dt forceful impaction of humeral head against anteroinferior glenoid rim when shoulder is dislocated anteriorly
o Bankart: inferior glenoid fxs w anterior GH jt dislocation.
o both assoc w anterior dislocation of humerus from GH jt and fracture of inferior glenoid rim from a posterior impaction injury.
• Which part of the clavicle most commonly fractures?
o Middle Clavicle Fx (80%0: medial fragment displaces superiorly dt pull of SCM, distal fragment displaces inferiorly dt weight of shoulder and upper extremity
• What is the significance of the elbow fat pad signs (anterior and posterior)?
o clinical signs of an intra-articular fx of elbow w displacement of anterior and/or posterior fat pads from bw the fibrous and synovial layers of humeral jt capsule.
o fat pads become visible (not normally) from intra-articular effusion and edema.
o 90% of children’s elbow fxs have visible posterior fat pads (less in adults; absence of sign doesn’t preclude fx).
o A posterior fat pad is always abnormal.
• What structures are involved in the most common fractures of the elbow in children and in adults?
o Kids: supracondlyar fxs (transverse or oblique fx above condyles) of distal humerus (60%),
o Adults: radial head and neck fxs (50%) (usu viewed as vertical radiolucent fx lines; “Chisel fx”). 2nd is olecranon (20%).
• What are the most common wrist fractures seen in each of the following age groups: children, young adults, elderly?
o Kids (6-10): Distal Radius Torus Fx; usu 2-4cm proximal to distal growth plate; have ductile bones!
o Young adults (15-40): Scaphoid Fx (PA view w ulnar deviation); occult fx, acute fx line mb not visible until 20 days post-injury, 70% at scaphoid waist
o Elderly: Colles’ Fracture (FOOSH); distal radius fx, ~20-35mm proximal to jt surface, distal fragment is angulated posteriorly; ulnar styloid also fx in 60%, brittle bones!
• Describe the difference between Colles’ and Smith’s fractures at the wrist.
o Colles: goes posterior “The collie goes in the back door”, FOOSH fx so wrist is exteneded
o Smith: goes anterior “Mr. & Mrs. Smith go in the front door”, dt fall w wrist in hyperflexion so “Reversed” Colle’s fx
• Discuss the vascular supply of the scaphoid and its effect in avascular necrosis and healing of this structure after fracture.
o 3 anatomical areas: proximal pole, waist, and distal pole.
o 2 sources of blood supply to scaphoid, one to waist, one to the distal pole.
o proximal pole does not have its own blood supply, so fx can → AVN (avascular necrosis) (~15%). AVN dx w x-ray (whiter than surrounding bone)
• What is the most common carpal bone to dislocate and in what direction?
o Lunate: dt hyperextension injury. tilts forward and anteriorly, disrupting its articulation w capitate, but maintains close approximation w anterior rim of radius
o Lateral view displays the anterior tilt
o PA view - Lunate looks like a triangle, apex points distally= “pie sign”
• What are barroom and boxer’s fractures of the hand?
o Boxer: Transverse fx of 2nd or 3rd MC neck. From impact of short, straight jabbing blow
o Barroom:Transverse fracture of 4th or 5th MC neck. from “roundhouse” blow
o Both: result in anterior angulation of MC head; shortening, rotation of distal fragment
• What is gamekeeper’s thumb?
o First metacarpophalangeal tear or rupture of ulnar collateral ligament of thumb
o Abduction stress view of thumb: widened ulnar side of MCP joint= instability
o Mb chip fracture, w small fragment from ulnar margin of proximal phalanx base
o MRI: ulnar collateral ligament lesion
• What are the common sites of a stress fracture?
o MTs: aka “march fracture”, “deutchlanders disease”
o Proximal tibia, calcaneus, distal fibula, hook of hamate, distal 1/3 clavicle
o L5 pars interarticularis (most common stress fracture in spine)
• How can stress fractures be detected on plain x-ray?
o 50% stress fxs never show x-ray findings
o Often occult; requires bone scan, MRI, or delayed plain film images (latent period = 10-21days)
• What imaging type(s) are most sensitve in detecting stress fractures?
o Bone scan is sensitive, not specific o CT may delineate fx but later o MRI (most sens) will show bone edema and fx line earlier than CT o SN + Sp: Periosteal response: local periosteal and endosteal cortical thickening
• What is the difference between spondylolisthesis and spondylolysis?
o thesis: one vertebra slips on another, usu anteriorly (anteriolisthesis). or posterior (retrolisthesis) or lateral (laterolisthesis).
o lysis: Pars interarticularis defect (w or w/o slippage aka spondylolisthesis). Mb pain at onset of lysis.
• What are the most common types of spondylolisthesis in the lumbar spine? Spinal level?
o 90% of all spondylolytic spondylolistheses involve L5 (most common cause in pediatrics)
o Most degenerative spondylolistheses at L4.
• What is spondylolytic spondylolisthesis? Etio?
o S: anterior displacement of a vertebra
o biomechanical stress: usu → pars interarticularis fracture (spondylolysis)
o 3 Subtypes:
o Subtype a: most common, stress (fatigue) fracture.
o Subtype b: elongation of pars w/o defect, dt repeated stress fracture w healing
o Subtype c: Acute pars fractures; rare
• What is degenerative spondylolisthesis? Etio?
o disc space, cartilage loss in facet joints → superior vertebra slip forward.
o 15-25% anterior slip.
o Usu F, >40
o No neural arch defect
• What is spondylolysis? Etio?
o defect in pars interarticularis of a vertebra
o Repetitive microtrauma: Congenitally slender pars may predispose to stress fx; acute fx rare; not seen in infants
• What are some common causes of stress fractures?
o Fatigue fx: mechanical stress at L/S lordosis
o Hyperextension loading (heavy backpack)
o Onset M/C after 5 yo: d/t upright posture and ambulation
o Premature walking
o Divers, gymnasts, pole-vaulters, weight-lifters
o Non-union d/t lack of immobilization
• What is the Meyerding’s grading system?
o Lateral lumbar projection, progressively anterior to S1. sacral base has 4 equal sections (1st posterior→ 4th anterior)
o Grade 1: posterior-inferior corner of L5 aligned w 1st division (1 -25% of sacrum promontory visible)
o Grade 2: 2nd division 26-50%
o Grade 3: 3rd division 51-75%
o Grade 4: 4th division 76-100%
o Grade 5: L5 completely slipped off anteriorly)
• What is an inverted/ reversed Napoleon hat sign?
o Meyerding grade 5
o Aka bowline of Brailsford, seen w significant anterolisthesis.
o L5 body slides forward (looks like upside down Napoleon hat). only if significant slippage of anterior portion of L5 off sacrum
o BL pars fracture of vertebrae allows slippage
o Mb no nerve damage or impingement, cauda equine follows normal path
