An introduction to the approach to fracture interpretation on radiographs, aimed at medical students. From the medical student radiology teaching website, svuhradiology.ie.
Cara Menggugurkan Kandungan Dengan Cepat Selesai Dalam 24 Jam Secara Alami Bu...
Fracture interpretation for medical students
1. Approach to Fracture
Interpretation For Medical
Students
Dr Rory O’Donohoe
Honorary Lecturer
Department of Radiology
St. Vincent’s University Hospital
Dublin 4
Ireland
www.svuhradiology.ie
2. How do we visualise fractures?
• When a fracture causes separation
of bone fragments, more x-ray
photons get through the gap and we
see a lucent (dark) line
3. How do we visualise fractures?
• When a fracture causes overlapping
of bone fragments, more x-ray
photons are blocked and we see an
area of increased density (more
white)
4. What radiographic views do we
need?
• To properly examine a bone or a
joint, we need at least two views
• Usually these views are obtained
at right angles to each other (for
example, AP and lateral)
• If the fracture is displaced in the
same direction as the x-ray beam,
it may only visible on an
orthogonal view (hence the need
for more than one view)
Lateral view of elbow, left shows effusion but no
fracture. AP view, right, shows the fracture line.
5. A little on the description of
projections…
• Know what PA and AP mean:
• They refer to the direction of the beam
• In postero-anterior (PA) projections, the beam is fired from
behind the patient and the detector is in front of them (and vice-
versa for AP)
• If in doubt as to whether it’s PA or AP, just call it a frontal
projection- this applies to chest radiographs too
6. Special cases
• Some fractures are often so hard to see that we need
more than two views (a scaphoid series involves four
views) – and even with these we frequently still have
difficulty diagnosing them
• Some fractures are better identified by their effect on
the soft tissues around them, for example fat pad
displacement in elbow fractures, as will be explained
later…..
7. Is it definitely a fracture?
• Some normal appearances can be mistaken for fractures
• Growth plates are a frequent source of confusion - if in doubt,
check the age of the patient
• Accessory ossicles often persist into adulthood and can usually be
identified by their classic locations (entire textbooks are dedicated
to cataloguing accessory ossicles)
• If in doubt as to whether it’s a fracture or not, remember you can
always correlate with clinical examination. Are they tender there?
8. How to describe fractures
• Medicine requires clear and reproducible ways to
describe things - it’s not just for exams!
• You need to have a clear knowledge of the terms used
to describe fractures
9. How to describe fractures
• Start with the easy stuff!
• Describe the study (e.g. “These are AP and lateral
radiographs of the right humerus.”)
• What is the age and sex of the patient?
• Don’t point at the image. If you see the fracture,
describe it…..
10. How to describe fractures
• What bone is broken?
• While this seems obvious, it requires that you remember all of
your anatomy!
• Many medical students are a little rusty on the carpal bones
and tarsal bones
• If you want to quickly revise, check out the anatomy section on
our website at
http://www.svuhradiology.ie/diagnostic-imaging/radiological-anatomy/
11. How to describe fractures
• What part of the bone is broken?
• For long bones we assess whether it’s the proximal epiphysis,
proximal metaphysis, diaphysis, distal metaphysis, distal
metaphysis
• In many of these, certain parts of the bone will have a
specific anatomical name (e.g. tibial plateau, radial head,
femoral neck), so you need to be familiar with these too
• For shorter bones (e.g. a middle phalanx in a finger), we
usually describe the location with the terms proximal, mid and
distal rather than metaphysis etc.
12. How to describe fractures
• Is the fracture comminuted?
• A comminuted fracture comprises more than two fracture
fragments
• This may determine whether the fracture can be treated in
cast or will require surgery
• Occasionally it can be difficult to be certain, in which case the
orthopaedic team may request a CT to further assess the
fracture
13. How to describe fractures
• Describe the fracture line
• Transverse, oblique, spiral – the majority of fractures can be
described with one of these terms
• Occasionally, fractures will be multidirectional, for example ‘t-
shaped’, ‘h-shaped’
15. How to describe fractures
• Is there displacement?
• e.g. “there is lateral displacement of the distal fracture
component”
• Is there angulation?
• e.g. “there is medial angulation of the distal fracture
component”
• As you would expect, the more displaced and/or angulated a
fracture is, the more likely it will require surgical intervention
16. Fracture of the distal radius
with severe dorsal displacement
and dorsal angulation
17. How to describe fractures
• Is the fracture intra-articular?
• Does the fracture line (or one of them if comminuted) involve
an articular surface?
• Intra-articular fractures are associated with a poorer long-term
outcome and can result in secondary osteoarthritis
• If a joint is involved, does the joint demonstrate normal
alignment?
• If not, is it dislocated (articular surfaces no longer in contact)
or subluxed (articular surfaces partly in contact)
• For example, ankle fractures are often associated with
subluxation of the joint
20. How to describe fractures
• Simple vs. compound fractures are more relevant to clinical
examination but should be considered
• Simple fractures involve the bone only whereas compound
fractures break the skin surface and are therefore prone to
infection
• Often we won’t be able to tell this by looking at radiographs,
but occasionally it will be obvious
21. Cases
• Now that you’ve been armed with all this background
information, here are 10 cases for you to review
• Practice describing each fracture as you would in an
exam
22. Case 1
• 30 year old with pain in the right ankle after a fall
25. Case 1
• AP and lateral radiographs of
the right ankle in a skeletally
mature patient
• There is an oblique, non-
displaced fracture of the
distal shaft of the right tibia
26. Case 2
• 27 year old with pain in the right shoulder after a
sports injury
28. Case 2
• AP radiograph of the right
shoulder
• There is a completely
displaced comminuted
fracture of the right clavicle at
the junction of the middle
and lateral thirds
29. Case 2
• The fracture is described as
comminuted as there are
three separate fracture
fragments (arrows)
30. Case 3
• 35 year old with pain in her toe after a night out
33. Case 3
• Frontal and oblique
radiographs of the left foot
• There is a minimally displaced
transverse fracture of the
distal shaft of the left third
proximal phalanx
34. • Note how difficult it is to see
the fracture on the frontal
projection (it’s just about
visible as a transverse dense
line)
• This is why we need two
views when assessing for
fractures
• In this case the projections
are frontal and oblique - the
projections aren’t necessarily
always at right angles to each
other
35. Case 4
• 40 year old with inversion injury of the right ankle
38. Case 4
• AP and lateral radiographs of
the right ankle
• There is a minimally displaced
spiral fracture of the right
distal fibula at the level of the
syndesmosis
39. Case 5
• 15 year old with pain in the left shoulder after a fall
42. Case 5
• Normal radiographs!
• Don’t be fooled by the left proximal
humeral growth plate (arrows)
• There appear to be two lines through
the left proximal humerus as the growth
plate runs obliquely through the plane
of the radiograph
• Note there are also growth plates visible
at the acromion and coracoid processes
• Remember in young patients to consider
if what you’re looking at might be a
growth plate
43. Case 6
• 87 year old with pain in the hip after a fall out of bed
51. Case 7
• Scaphoid fractures can be notoriously
difficult to see. Four views are obtained
when a scaphoid fracture is suspected.
• A comminuted fracture of the waist of
the left scaphoid is visible on this
scaphoid series - this example is easier
to spot than most scaphoid fractures
• If a scaphoid fracture is still suspected
despite not being visible on radiographs,
the wrist should be immobilised and
repeat radiographs performed in 7-10
days at which time the fracture may be
more apparent.
52. Case 8
• 40 year old with pain in the right elbow after a fall
55. Case 8
• Not all fractures are visible on
radiographs, particularly in the
acute setting
• There may however be signs of
the fracture in the surrounding
soft tissues
• The classic example is in the
elbow where an elbow joint
effusion causes elevation of the
anterior and posterior fat pads
56. Case 8
• Remember, fat allows the
transmission of a relatively large
number of x-ray photons and
therefore appears dark
• Note the two triangles of fat anterior
and posterior to the distal humerus
• These are the fat pads that have been
displaced by fluid in the elbow joint
• In practice, this is presumed to be due
to a radial head fracture although the
fracture line is not visible
57. Case 9
• Pain in the right ankle after jumping from a height
60. Case 9
• No fracture!
• There is a boney density adjacent the
lateral cuneiform
• This is an accessory ossicle
• Note how rounded it appears, and it
doesn’t have the sharp edges of the
fractures in the previous cases
• Details of the common locations of
accessory ossicles can be found in
textbooks (and on google)
64. Case 10
• Fracture of the distal radius
• Always remember to look
at the edge of the film!
65. Summary
• It’s important to have a systematic approach to
describing fractures, incorporating all the essential
features such as displacement, comminution and
intra-articular extension
• We hope that this tutorial has made you more
confident in your approach to radiographs of
fractures
