X-Ray

Rapid Review

• Background
  • Abdominal X-ray typically has a limited role in emergency medicine, but can be used to work-up constipation, bowel obstructions, or perforated viscus. 
• Common Findings
  • Small Bowel Obstruction
    • Dilated small bowel (>3 cm) containing air fluid levels
  • Large Bowel Obstruction
    • Colonic distention (>6 cm)
    • Cecal distention (>9 cm) 
  • Perforated Viscus
    • Free air under the diaphragm

Pearls

Deep Dive

• The Abdominal X Ray: A relic or a reliable tool? (Taming the SRU)

Rapid Review

• Background
  • Ankle X-ray is used primarily to evaluate for fractures and dislocations. Commonly indicated for ankle pain following falls, sports injuries, or suspected infections. Ottawa ankle rules can be used to assess the need for imaging. 
• Common Findings
  • Calcaneal fracture
    • Fracture line usually evident, but may require axial calcaneal projection to fully visualize.
    • Bohler’s angle less than 20 degrees suggests calcaneus fracture
  • Distal fibula fracture
    • Fracture line usually evident. May also show widening of ankle mortice joint spaces.
  • Jones fracture
    • Fracture line usually evident along the proximal 5th metatarsal
  • Talar Neck fracture
    • Fracture line typically evident on lateral or oblique foot views
  • Talonavicular dislocation
    • Usually obvious. May be associated fractures of calcaneus, cuboid, or navicular bones.

Pearls

Deep Dive

• Ankle X-Rays (Don’t Forget the Bubbles)

Rapid Review

• Background
  • The chest X-ray is a commonly performed test in the emergency department setting and can be used to rapidly detect a wide variety of abnormalities. It can screen for pneumothorax, pneumonia, pleural effusion, pulmonary edema, abnormal heart size/borders, and rib fracture, among other conditions.
• Common Findings
  • Aortic Dissection
    • Widened aortic knob
  • Heart Failure
    • Kerley B-lines
    • Enlarged cardiac silhouette
  • Tension Pneumothorax
    • Air-filled pleural space (lack of vascular markings)
    • Shifted mediastinum
    • Deviated trachea
  • Pneumonia
    • Consolidation
    • Hazy heart border
    • Sharp diaphragm border
  • Pleural Effusion
    • Fluid-filled space (white
    • Meniscus sign (concave surface)
    • Obscured costophrenic angle and hemidiaphragm
  • Pulmonary Embolism
    • Westermark Sign (dilation of pulmonary vessels)
    • Hampton Hump (wedge shaped pulmonary opacity)
  • Sarcoidosis
    • Bilateral hilar adenopathy

Pearls

Deep Dive

• How to read chest x-rays (International Emergency Medicine Education Project)

Rapid Review

• Background
  • C-Spine X-ray can be used to evaluate cervical spine trauma. The decision to image is commonly guided by Nexus criteria and the Canadian cervical spine rule. 
• Common Findings
  • Anterior Cervical Subluxation
    • Uneven spinous processes
  • Compression Fracture
    • Anterior and posterior heights of affected vertebra will differ by 20% or more (anterior will usually be shorter than posterior)
  • Hangman’s Fracture
    • Anterior displacement of C2, caused by bilateral fracture of the pars interarticularis.
  • Hyperflexion Teardrop Fracture
    • Injury most commonly at C5/C6
    • Fractures at anterior inferior aspect of vertebral bodies, widening spinous process, loss of normal curvature, and loss of vertebral height
  • Jefferson Fracture
    • Burst fracture of C1
    • Lateral masses of C1 will not align with masses of C2
  • Clay Shoveler’s Fracture
    • Spinous process fracture
    • Fracture line usually clearly seen. Significant displacement common

Pearls

Deep Dive

• Cervical Spine Imaging in Trauma (SAEM)

Rapid Review

• Background
  • Elbow X-ray is used to assess the bony structure of the elbow. Used primarily for evaluating fractures and dislocation. 
• Common Findings
  • Radial head fracture
    • Fracture line or anterior fat pad (“Sail sign”)
  • Supracondylar fracture
    • Fracture line or anterior/posterior fat pads
    • If ⅓ of the capitellum lies anterior to the anterior humeral line, fracture is likely.
  • Olecranon fracture
    • Cortical disruption of the olecranon, most evident on lateral x-ray
  • Monteggia fracture-dislocation
    • Ulnar shaft fracture w/ radial head dislocation
  • Elbow dislocation
    • Posterolateral displacement most common

Pearls

Deep Dive

• EMRad: Can’t Miss Elbow Injuries (ALiEM)

Rapid Review

• Background
  • Foot X-ray is used primarily to evaluate for fractures or dislocations. Commonly indicated for injuries related to falls, impact from heavy weight, or motor vehicle accidents
• Common Findings
  • Calcaneal fracture
    • Fracture line usually evident, but may require axial calcaneal projection to fully visualize.
    • Bohler’s angle less than 20 degrees suggests calcaneus fracture
  • Jones fracture
    • Fracture line usually visible along the 5th metatarsal
  • Lisfranc Injury
    • Misalignment at the tarasal-metatarsal joint, typically the 2nd or 3rd metatarsal
    • Frontal and oblique views are best for detection of this injury.
  • Metatarsal/Phalanx fracture
    • Fracture lines usually evident
  • Talar Neck fracture
    • Fracture line most visible on lateral or oblique foot views
  • Talonavicular Dislocation
    • Usually obvious. May be associated fractures of calcaneus, cuboid, or navicular bones.

Pearls

Deep Dive

• Foot Radiograph (Radiopaedia)

Rapid Review

• Background
  • Hand X-ray is used primarily for evaluating fractures and dislocations. Common indications include FOOSH injuries, fight injuries, accidents with tools (eg. hammers)
• Common Findings
  • Bennett Fracture
    • Intra-articular fracture of the first metacarpal w/ remainder of first metacarpal dislocated dorsally and laterally.
  • Boxer Fracture
    • Transverse fractures through 5th metacarpal neck
    • Distal fragment usually has palmar angulation
  • CMC Joint Dislocation
    • Loss of “zig-zag” joint space at the base of the dislocated metacarpals
  • Epibasal Thumb fracture
    • Two-piece extra-articular fracture of the base of the first metacarpal
  • Gamekeeper Thumb
    • Joint space widening or avulsion fracture at the base of the 1st MCP joint.
  • Mallet Finger
    • May see bony avulsion (triangular fragment at the dorsal side of the base of the distal phalanx)
  • Phalanx/Metacarpal Fracture
    • May be intra or extra articular fractures along the phalanx/metacarpal
  • Rolando Fracture
    • Comminuted basal thumb fracture with dislocation of the main fragment.
  • Volar Plate Fracture
    • Avulsion fragment on the palmar side of the base of the middle pharynx

Pearls

Deep Dive

• Interpretation of Hand & Wrist Radiographs (Taming the SRU)

Rapid Review

• Background
  • Knee X-ray is used primarily to evaluate for fractures and dislocations. Commonly indicated for knee pain following MVC, sports injuries, or suspected infections.
• Common Findings
  • ACL avulsion fracture
    • Fracture or loss of clarity of the tibial spines.
  • Fibular neck fracture
    • Fracture line. May need oblique view to fully expose fibula
  • Patellar fracture
    • Usually transverse, but may be comminuted. May see fat-fluid level on lateral view
  • Patellar tendon rupture
    • “Patella alta” (high riding patella from tibial tubercle)
  • Segond fracture
    • Avulsion fracture at the lateral margin of the tibia
  • Supracondylar femur fracture
    • Fracture line typically evident. Often associated w/ femoral neck fractures.
  • Tibial plateau fracture
    • Focal increased density below plateau or lateral displacement of the lateral tibial margin. 

Pearls

Deep Dive

• Knee X-Rays (Don’t Forget The Bubbles)

Rapid Review

• Background
  • Lumbar spine X-rays are typically used to identify fractures.  Commonly performed following injuries sustained from motor vehicle accidents, falls, and heavy lifting.
• Common Findings
  • Burst fracture
    • Pedicles widened at the level of injury. May have loss of vertebral height or fracture line on lateral view
  • Compression fracture
    • Anterior and posterior heights of affected vertebral height will differ by 20% or more.
  • Flexion-Distraction injury
    • Wedge fracture of the vertebral body w/ fracture or distraction of the facets and spinous processes.
  • Transverse Process fracture
    • Fracture line may be seen with careful windowing on plain film, though CT is imaging modality of choice.
  • Vertebral fracture-dislocation
    • Posterior displacement of vertebrae near the thoraco-lumbar junction, along with vertebral fractures

Pearls

Deep Dive

• Lumbar X-Ray Interpretation (Geeky Medics)

Rapid Review

• Background
  • A pelvic X-ray shows the bony structure of the pelvis. It can rapidly assess fractures in the trauma patient. It will also provide information about both proximal femurs and the hip joints.
• Common Findings
  • Acetabular Fracture
    • Asymmetric acetabuli
  • Femoral Neck Fracture
    • Jagged contours on affected side
    • Sclerotic bone (from bone impaction)
    • Asymmetry between femoral heads
  • Main Pelvic Ring Fracture
    • Widened SI joint
    • Widened pubic symphysis
  • Posterior Hip Dislocation
    • Loss of congruence between acetabulum and femoral head
  • Pubic Ramus Fracture
    • Fracture lines through public rami
    • Disruption in contours of obturator foramen
  • Sacral Fracture
    • Broken arcuate line on affected side

Pearls

Deep Dive

• Back to Basics: Pelvic X Rays (Taming The SRU)

Rapid Review

• Background
  • Shoulder X-ray is used to assess the bony structure of the shoulder. Useful for identifying fractures or dislocations. 
• Common Findings
  • Anterior shoulder dislocation
    • Humeral head will lie inferior and medial to glenoid fossa (AP view)
  • Posterior shoulder dislocation
    • Widened glenohumeral joint > 6mm
    • “Lightbulb” sign (AP)
  • AC Joint dislocation
    • Elevated or displaced clavicle
    • May need weight-bearing films to see
  • Clavicular fracture
    • Fracture line or deformity, typically in the middle or distal thirds
  • Humeral head fracture
    • Fracture line or deformity, typically at the humeral neck or the greater trochanter
  • Hill Sachs Lesion
    • Vertical white line in humeral head, or notch taken out of lateral humeral head.
  • Bankart Lesion
    • Defect on the anteroinferior aspect of glenoid

Pearls

Deep Dive

• Shoulder X-Ray Interpretation (Geeky Medics)

Rapid Review

• Background
  • Wrist x-rays are commonly used to work-up wrist trauma, bony tenderness, non-traumatic deformities
• Common Findings
  • Scaphoid Fracture
    • Fracture site most commonly at waist of scaphoid
    • Not always seen on X-ray
  • Perilunate Dislocation
    • Capitate dislocated dorsally from cup of lunate, but articulates normally with radius
    • Scaphoid fractures present in over 50% of cases
  • Barton Fracture
    • Intra-articular fracture of distal radius
  • Chauffeur Fracture
    • Intra-articular fracture of the radial styloid process
    • May have scapholunate dislocation and/or ulnar styloid fracture
  • Colles Fracture
    • Extra-articular distal radius fracture with dorsal angulation.
    • Commonly associated with ulnar styloid fracture
  • Galeazzi Fracture
    • Distal radius fracture w/ radio-ulnar joint dislocation
  • Greenstick Fracture
    • Fracture does not go all the way through the bone
    • Cortical break on one side, bend/angulation on other side

Pearls

Deep Dive

• EMRad: Radiologic Approach to the Traumatic Wrist (ALiEM)