X-rays and the Upper Limbs Flashcards

1
Q

Why is one x-ray view sometimes not enough to visualise a fracture?

A

Fractures may be invisible, alignment cant be fully assessed

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2
Q

What is normally the best number of x-ray views to be taken?

A

Two views

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3
Q

What are some examples of when more than two x-ray views are needed?

A

Cervical spine = AP, lateral and odontoid peg needed

Scaphoid = AP, lateral and two obliques needed

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4
Q

What are some ways fractures can appear on x-rays?

A

Lucency crossing bones, cortical expansion, spiral/transverse, comminution, joint involvement, angulation, displacement, impaction, avulsion

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5
Q

What are some bony entities which superficially resemble acute avulsion fractures?

A

Sesamoid bones, accessory ossification centres and old non-united fractures

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6
Q

How can you tell acute avulsion fractures apart from their mimics?

A

Avulsion fracture fragments are incompletely corticated = all mimics have a completely corticated contour

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7
Q

What are some joints that can be used to assess bony alignment?

A

Acromioclavicular, glenohumeral , elbow (radio-capitellar and humero-capitellar), lateral wrist

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8
Q

Where may fat density be seen on a normal x-ray?

A

Anterior to the distal humerus

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9
Q

What is the posterior fat pad sign?

A

Visible posterior fat pad = indicates elbow trauma which has caused an effusion

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10
Q

How are children’s bones different form adult bones?

A

They are soft so “bend and bow” rather than £snap and splinter” = buckle fracture, plastic bowing
Fractures are often incomplete = greenstick fracture

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11
Q

What is it common for ligaments and tendons in children to do?

A

Avulse their soft bony attachments

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12
Q

How may a physis appear on an x-ray?

A

Lucency between the epiphysis and metaphysis = may look like a fracture

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13
Q

Why is the physis prone to injury?

A

It is the weakest part of developing bone

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14
Q

Where is the epiphysis always seen on normal x-rays?

A

Always centred on the metaphysis

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15
Q

What kind of fractures are Salter-Harris fractures?

A

Growth plate (physis) fractures

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16
Q

What may be an indication of a non-accidental injury (NAI)?

A

An injury that doesn’t fit with the carers description of the history

17
Q

Why do bones and joints form rings?

A

To help share the transmission of force and increase strength (e.g spinal canal, pelvis)

18
Q

Why should you expect at least two disruptions when a bony ring is injured?

A

Its difficult to disrupt a ring in only one place (some disruptions may be fractures and others dislocations)

19
Q

What foreign objects may be seen on an x-ray?

A

Dense objects = metal and glass

Plastic and wood are often invisible

20
Q

When should you suspect a pathological fracture?

A

When the bone abnormality seems out of proportion to the mechanism of injury

21
Q

What are pathological fractures typically a result of?

A

Normal stresses on a weakened skeleton

22
Q

What are some examples of pathological fractures?

A

Colles fracture, radial buckle fracture, scaphoid fracture and surgical neck of humerus fracture

23
Q

What are some features of a Colles fracture?

A

Occur in elderly with osteoporosis, dorsal angulation of the radius, associated with ulnar styloid fracture

24
Q

What are some features of a radial buckle fracture?

A

Occurs in children with soft bones, only half of them are visible

25
What are some features of a scaphoid fracture?
Occurs in relatively young men, pain in anatomical snuffbox, commonly occurs mid-scaphoid
26
What are some features of a surgical neck of humerus fracture?
Occurs in post menopausal females, sclerosis indicates impaction, often comminuted, can damage axillary nerve
27
What are some commonly missed upper limb injuries?
Posterior shoulder dislocation, supracondylar fracture, scaphoid fracture, Bennet's fracture
28
How should a posterior shoulder dislocation be imaged?
Oblique view should always be obtained = shows humeral head lies posterior to the articular surface of the glenoid
29
Why are AP views not suitable for imaging a posterior shoulder dislocation?
Lack of displacement makes it difficult to appreciate
30
What are some features of a supracondylar fracture?
Found be assessing the humero-capitellar alignment Has visible posterior fat pad Can damage brachial artery acutely and will malunite if untreated
31
How should a scaphoid fracture be imaged?
Can be invisible despite multiple views | Repeat the x-ray after 10 days and MRI can be useful in confirming/excluding a fracture
32
What may a scaphoid fracture cause?
Proximal scaphoid blood supply can be disrupted, making it prone to non-union and avascular necrosis = may cause early wrist osteoarthritis
33
What is involved in a Bennett's fracture?
Articular surface of wrist of first metacarpal base
34
What may a Bennett's fracture lead to?
Tendons pulling on the thumb distal to the fracture causes displacement = can lead to deformity, dysfunction and osteoarthritis