TIPS FORINTERPRETING X-RAYS IN TRAUMAKENG SHENG CHEW, MD, MMED (Emerg Med) Senior Lecturer/Emergency Medicine Physician,School Of Medical Sciences, Universiti Sains Malaysia
CERVICAL SPINE• In patients with major trauma – 5% have an unstable cervical spine – 2/3rd of this 5 percent present without initial neurologic deficit. • Chiles III BW, Cooper PR. Acute Spinal Injury. New England Journal of Medicine 1996; 334 (8):514-20.• Site of Injuries: Cervical spine (60%), Thoracolumbar junction (20%), Thoracic (15%), Lumbosacral Spine (5%) • Savitsky E, Votey S. Emergency Department Approach To Acute Thoracolumbar Spine Injury. The Journal of Emergency Medicine 1997; 15 (1):49-60.
CERVICAL SPINE• Ensure visualization of ALL cervical vertebrae as well as the atlanto-occipital and C7-T1 articulations• Cervical region – most commonly injured part due to – its flexibility (most mobile) and – its exposure • Savitsky E, Votey S. Emergency Department Approach To Acute Thoracolumbar Spine Injury. The Journal of Emergency Medicine 1997; 15 (1):49-60.
INTERPRETING CERVICAL X-RAY• Look at: Mnemonic:• A = Alignment „ABCs‟• B = Bones• C = Cartilaginous and• S = soft-tissues• A = smooth, unbroken alignment of three lines
CASE STUDY A 41-year-old man was brought to the ED following a motor vehicle collision in which he was an unrestrained driver whose vehicle hit a roadway median divider. The automobile driver‘s air bag deployed.
HANGMAN FRACTURE The usual site of fracture is because it is the weakest part of the C2 neural arch.
THE „TRUE‟ HANGMAN FRACTURE VSASPHYXIATION DUE TO HANGING
HANGMAN FRACTUREThe typical mechanism of injury causing hangman‘s fractures.Hyperextension and axial compression occur when the head impactson the windshield. This fractures the posterior skeletal elements ofthe cervical spine.
PSEUDOSUBLUXATION • Malalignment of the posterior vertebral bodies is more significant than that anteriorly • Two most common causes of C2-C3 malalignment are pseudosubluxation and hangmans fracture.
PSEUDOSUBLUXATION • To distinguish these * two, draw a Swischuk * line from the base of spinous process of C1 * to the base of the spinous process of C3. • The base of C2 should normally not be more than 2 mm from the Swischuk line
BONES• Vertebral bodies below C2 have a uniform, square (cuboidal) shape.• An increase in density may indicate a compression fracture.
CARTILAGINOUS STRUCTURES• The intervertebral spaces should be uniform.• Widening of these or the interspinous distance may indicate an unstable dislocation.• An increase in interspinous distance of 50% suggests ligamentous disruption.
SOFT TISSUES• Prevertebral soft tissue• C1 – C4: 50% of the AP width of a vertebral body• C5 – C7: the AP width of one vertebral body ‗2 – 6‘ Rule C2 = 6 mm C6 = up to 2 cm
PRE-DENTAL SPACE • Predental Space < 3 PRE-DENTAL SPACE mm in adult • < 5 mm in children • Widening of predental space – suspect Jefferson‘s fracture of C1
JEFFERSON FRACTURE A 37-year-old man lost his balance while standing on a subway platform and fell five feet, head first onto the tracks. He had consumed an alcoholic beverage prior to his fall. Fortunately, train was not entering the station at the time. He was extricated from the tracks, immobilized, and brought to the ED.
OPEN MOUTH VIEW• The distance between the odontoid and the lateral masses of C1 should be equal.• Inequality may be due to head rotation. It A + B >7 mm, this suggests a disruption of the transverse ligament
PREDENTAL SPACE ABNORMALITIES Predental space Significance distance3 – 6 mm Partial disruption of the transverse ligament6–10 mm Disruption of the transverse ligament, but intact alar and Accessory ligaments> 10 mm Complete ligamentous instability
CHECKLIST FOR A CXR• Name, ID particulars, etc• Check for the ‗L‘ or ‗R‘ marker.• To prevent missing dextrocardia• Quality of the film• Is the film well-centered?• Is the patient‘s position rotated?• Is the exposure and X-ray penetration adequate?
IS IT AP or PA VIEW?CRITERIA PA VIEW AP VIEWSpinous process Prominent Straightlamina inverted ‗V‘ shapeScapula Out of the chest Inside wallClavicle direction Medial end is Straight lowerHeart size Not enlarged Appears enlarged
CHECKLIST• Penetration – the spine should be ‗just seen‘ through the mediastinum• Well-centeredness – the medial ends of the clavicicle should be equa-distant from midline• Exposure - scapular end should be outside of the lung fields• In full inspiration, 6th anterior or 10th posterior rib should touch the hemidiaphgram
DISTORTIONS ON A PORTABLE AP X-RAY• Rotated positioning of the patient—apparent shift of trachea and mediastinum• Poor inspiration—crowded lung markings at the bases• Suboptimal exposure—over or under-penetrated• Cardiac enlargement• Widened and indistinct mediastinum• Superimposed extrathoracic objects—spine immobilization boards, tubes, monitoring wires, and clips
PARA-TRACHEALSTRIPE• The right paratracheal stripe is a thin layer of connective tissue that lies along the right tracheal wall adjacent to the right lung.• It is normally no more than 5 mm thick.• Widening >1 cm is a sign of pulmonary venous hypertension (e.g., CCF)
HEMIDIAPHRAGM• The highest point of the right diaphragm is usually 1–1.5 cm higher than that of the left. Each costophrenic angle should be sharply outlined.
ASSESSING FOR FLATTENING OFHEMIDIAPHRAGM• The highest point of a hemidiaphragm should be at least 1.5 cm above a line drawn from the cardiophrenic to the costophrenic angle.
Remember: Tension pneumothorax is a clinical diagnosis, NOT a radiological diagnosis
Deep sulcus sign: abnormal deepening and lucency of the left lateral costophrenic angleWhen the patient is supine, a pneumothorax collects anteriorly andmay be impossible to detect. A large pneumothorax may widen thecostophrenic sulcus—the ―deep sulcus‖ sign
QUANTITATIVE MEASUREMENT OFPNEUMOTHORAX SIZE Rhea (1981): Ptx % = 5 + 9* AID (after Choi 1998) Collins (1995): Ptx % = 4 + 14 * AID Light formula: Ptx % = (1 - x3/y3)*100 ACCP (2001): ―small‖ a < 3 cm; ―large‖ a 3 cm BTS (2003): ―small‖ m < 2 cm; ―large‖ m 2 cm where Average interpleural distance (AID) = (a+b+c)/3
QUALITTATIVE CLASSIFICATION• More recent guidelines have proposed using single measurements to determine patient care.• Only two sizes of pneumothorax are distinguished: small and large.• Small pneumothoraces can be managed by observation, as long as the patient is stable, has only mild symptoms, and has no underlying lung disease.• Large pneumothoraces need chest tube or catheter aspiration to reexpand the lung.
DIFFERENCES BETWEEN ACCP VS BTSGUIDELINES• The American College of Chest Physicians (ACCP) proposed using an apex to cupola distance of 3 cm to distinguish small from large pneumothoraces• The British Thoracic Society (BTS) uses an average pneumothorax width of 2 cm to distinguish large from small pneumothoraces, although the exact method of measurement is not specified.
RADIOLOGIC FEATURES DUE TOMEDIASTINAL HEMATOMA• Wide mediastinum• Indistinct or distorted aortic knob or proximal descending aorta• Opacification of the aorticopulmonary window• Wide right paratracheal stripe• Left paraspinal line displaced and extending superior to aortic knob
RADIOLOGIC FEATURES DUE TOMEDIASTINAL HEMATOMA• Left apical pleural cap• Right paraspinal line displaced• Mass effect due to periaortic blood at the aortic arch• Trachea or nasogastric tube displaced to the right• Depressed left mainstem bronchus
2 – 4 mm < 5 mm in adults < 10 mm in adolescents
CHECKLIST FOR PELVIC X-RAY• Look for symmetry of the hemipelvis• Scrutinize the three ‗rings‘ for fractures – Main pelvic inlet – Obturator foramen• Sacroiliac joints – Normal width 2 – 4 mm• Symphysis pubis – < 5 mm in adults – Up to 10 mm in children – Superior surfaces should align or offset < 2 mm
CHECKLIST FOR PELVIC X-RAY• Look for special radiographic landmarks• Iliopubic line• Ilioischial line• ‗U‘ curve and teardrop sign• Shenton line
RADIOGRAPHIC LANDMARKS OF PELVICX-RAYRadiographic “U” is theinferior lip of the anteriorarticular surface ofacetabulum.Radiographic teardropis composed of theilioischial line, theacetabular articularsurface, and theradiographic ―U.‖
THE SHENTON LINE• It is an imaginary line drawn along the inferior border of the superior pubic rami (superior border of obturator foramen) and along the inferiomedial border of the neck of femur. The line should be smooth and continuous
THE WATERS VIEW• Also known as Occipito-mental view (O-M view)• The Waters view is the most important view and by itself is probably a sufficient screening radiograph for patients with facial injuries. Occipito-frontal view To visualize frontal sinuses, superior orbital rim, and ethmoid air cells
WRIST ARCS (PA VIEW) Three arcuate lines can be drawn along the carpal articular surfaces Approximately equal distance (usually 1 to 2 mm) between each of the carpal bones 1. Disruption of these curves or 2. Widening of the carpal spaces implies carpal ligament disruption and carpal instability
THE TERRY THOMAS SIGNScapholunate dissociation
SCAPHOID FRACTURE• Most common carpal fracture (more than 60% of all carpal fractures) – Highest incidence of avascular necrosis of carpal bone – Lunate Fracture (Keinbock‘s disease) – (Note: Most common wrist fracture - Distal radius)• Commonly seen in young adults age 15 to 30 and occurs after a fall on the outstretched hand• Rare in skeletally immatured individuals because of the relative weakness of distal radius compared to scaphoid
COLLES‟ FRACTURE A - showing Posteroanterior view shows fracture and shortening of radius B - Lateral view shows typical dorsal displacement and angulation of radial fracture. (From Propp DA, Chin H: Forearm and wrist radiology
SMITH‟S FRACTURE Open reduction usually necessary. Closed reduction often unsuccessful due to flexor muscle pull.
BARTON FRACTURE Volar Barton‘s FractureBarton‘s fracture is an oblique intraarticularfracture of the rim of the distal radius, withdisplacement of the carpus along with thefracture fragment.
COLLES‟ VS BARTON‟S Colles or Smith – Extra- articular Barton‘s – Intra-articular In Barton‘s Fracture, surgical fixation is usually necessary when over 50% articular surface is involved or fragment not adequatelyBarton’s Fracture reduced Colles’ Fracture
ROLANDO VS BENNETT‟S FRACTURERolando fracture (comminuted;worse prognosis) Bennett fracture
RADIUS AND ULNA SHAFT FRACTURES• Because of protection by surrounding muscles, most radial shaft fractures require significant force and most have concurrent ulna fractures• Also, non-displaced fractures are rare• In ulna shaft fractures, solitary fracture of ulna may occur, often called nightstick fracture since it can be caused when stuck with a blunt object while self-defencing.
MONTEGGIA‟SFRACTUREIs a fracture at the junctionof the proximal and middlethirds of the ulnaassociated with anteriordislocation of the proximalradial head
Involves theGALEAZZIS FRACTURE junction of the middle and distal thirds of the radius, with an associated dislocation or subluxation of the DRUJ. Mnemonics: MU-GR Monteggia = ULNA Galeazzi = RADIUS
ANATOMY OF THE ELBOW Secondary growth centers of the elbow Mnemonic: “CRITOE”
OSSIFICATION CENTERSOssification Center Age appearing radiologicallyC = Capitellum 1 year oldR = Radial Head 3 years oldI = Internal epicondyle 5 – 7 years oldT = Trochlear 9 – 10 years oldO = Olecranon 9 – 10 years oldE = External epicondyle 9 – 10 years old Scaletta & Schaider, 2001
ANTERIOR HUMERAL LINE This line passes through the middle one third of the capitellum in bones that are not injured
RADIOCAPITELLAR LINE If radiocapitellar line does not pass through capitellum, a dislocated radial head is suspected
ANTERIOR AND POSTERIOR FAT PADS Anterior fat pad with sail sign appearance (due to joint effusion) Normally anterior fat pad is seen only as an anterior narrow strip of lucency but the posterior fat pad is not seen as it is hidden in the olecranon fossa. Posterior fat pad
ANTERIOR ANDPOSTERIOR FAT PADSAnterior fat pad displacement in thelateral view suggests effusion, but if theposterior fat pad is visible at all, an elbowfracture is likely.In the absence of trauma, the presenceof a fat pad suggests other causes ofeffusion (e.g., gout, infection, bursitis)Search hard for occult fractures, which are:1. Radial head fracture (in adults)2. Supracondylar fracture (in children)
Discuss the abnormalities seen Lateral view AP View
SUPRACONDYLAR FRACTURES• Most frequent elbow fracture in children, accounting for 50-60% of cases – Most occur in children aged 3-10 years, with a peak incidence in those aged 5-8 years• 10% have radial pulse loss temporarily, most often as a result of swelling and not direct brachial artery injury.• Reducing the fracture, avoiding flexing the elbow more than 90 degrees, and elevating the arm help prevent secondary obstruction to arterial flow.
Relative ligamentouslaxity in childhoodallows the elbow tohyperextend, and withhyperextension, theolecranon transmitsthe load into abending force on thedistal humerus in thesupracondylar region.
10-POINT CHECKLIST IN INTERPRETINGELBOW X-RAY• 1. Examine the anterior fat pad• The presence of an anterior fat pad is normal. It should be small and appear to be flat against the anterior surface of the humerus.• If it is large or it appears to be triangular in shape (sail shape) as if its lower tip is being displaced upwards, this indicates the presence of an elbow joint effusion
10-POINT CHECKLIST IN INTERPRETINGELBOW X-RAY• 2. Look for the presence of a posterior fat pad.• A posterior fat pad is always an abnormal sign and indicates the presence of an elbow joint effusion• 3. Examine the anterior humeral line.• If this line fails to bisect the capitellum, this indicates the presence of a fracture in the supracondylar region displacing the capitellum (usually posteriorly) or a Salter-Harris Type I fracture between the capitellum and the distal humerus.
10-POINT CHECKLIST IN INTERPRETINGELBOW X-RAY• 4. Examine the radial head• The shape of the radial head should show a smooth metaphysis. Any angles in the metaphysis may indicate a radial head fracture.• 5. Examine the radiocapitellar line• The radius should point directly at the capitellum in all views. If the radius does not point directly at the capitellum, this indicates a dislocation of the radial head.
10-POINT CHECKLIST IN INTERPRETINGELBOW X-RAY• 6. Count the number of ossification centers• CRITOE sequence• 7. Check for the Hourglass sign OR Figure-of-8 shape at the distal humerus to indicate that the X- ray is a true lateral view• An oblique view of the elbow may obscure some radiographic findings
10-POINT CHECKLIST IN INTERPRETINGELBOW X-RAY• 8. Look carefully at the distal humerus• Any lucencies indicating a supracondylar fracture• 9. Examine the olecranon and the remainder of the ulna for irregularities in the cortex.• An ossification center over the olecranon may resemble a fracture. The presence or absence of tenderness over the olecranon may help to establish a diagnosis• 10. Correlate X-ray with clinical picture
10 THINGS TO LOOK FOR IN ELBOW X-RAY1. Anterior fat pad2. Posterior fat pad3. Anterior humeral line.4. Radial head contour.5. Radiocapitellar line6. Ossification centers - CRITOE7. Hourglass sign8. Distal humerus9. Ulna/Olecranon10. Clinical correlation
ANKLE MORTISE VIEW Check joint space around talus for symmetry/disruption Search for fractures of distal tibia and fibula The lines formed between the articular surfaces should be parallel throughout the tibiotalar and talofibular components of the joint
MALLEOLAR FRACTURES• The stability of an isolated lateral malleolar fracture depends on the location of the fracture in relation to the level of the tibiotalar joint.• Medial malleolar fractures are commonly associated other fractures/disruption• Therefore, the identification of a medial malleolar fracture demands a careful examination of the entire length of the fibula for tenderness (Maisonneuve fracture)
LISFRANC‟S JOINT Lisfranc‘s Joint - Bases of the first three metatarsals with their respective cuneiforms and the fourth and fifth metatarsals with the cuboid
CALCANEAL INJURIESAn angle of less than 20 degrees suggests acompression fracture of calcaneum Boehler‘s angle of 20 to 40 degrees gives the best balance of sensitivity and specificity for fracture detection