Upper Limb Trauma X-rays Flashcards
(29 cards)
History features that suggest that an X-ray should be done?
Mechanism of injury:
• High velocity injuries are more likely to cause a fracture than low velocity
• Impaction/rotation/distraction
Site of bone tenderness/presence of deformity
Patient age
Why is one X-ray view rarely enough to find fractures?
Fractures may be invisible
Alignment cannot be fully assessed
Two views are often enough to assess the region
Special circumstances in which more than 2 X-ray views are used?
Cervical spine:
• AP view
• Lateral view
• To view the odontoid peg, the patient must open their mouth
Scaphoid requires 4 views, as it is prone to complications:
• AP
• Lateral
• 2 oblique views
Different types of fracture appearances?
- Lucency crossing bone
- Cortical extension/hypertrophy
- Spiral/transverse fractures - occur when a rotating force is applied to the bone
- Comminuted fracture - bone breaks into more than 2 fragments, usually following high-impact trauma
- Joint involvement
- Angulation - fragments of bone are at angles to each other; usually encountered after a punch injury
- Displacement - 2 ends of the bone fragments are not lined up straight
- Impaction - bone fragments are driven into one another
- Avulsion - separation of a small fragment of bone cortex at the site of attachment of a ligament/tendon
What bony entities on X-ray mimic acute avulsion fractures?
All of these have a COMPLETELY CORTICATED CONTOUR:
• Sesamoid bones (embedded within tendon/muscle)
• Accessory ossification centres
• Old, non-united fractures
Areas to assess bony alignment in the upper limb?
Acromioclavicular joint
Glenohumeral joint
Elbow:
• Radio-capitellar (drawing a line down the middle of the radius should meet the capitulum)
• Humero-capitellar (drawing a line down the middle of the capitulum should bisect the capitulum)
Lateral wrist
Soft tissue abnormalities and normal features seen around the distal humerus on X-ray?
Fat density may be seen anterior to the distal humerus on normal X-rays
If an elbow effusion is present (trauma is a common cause), a displaced fat pad becomes visible posterior to the distal humerus (POSTERIOR FAT PAD SIGN)
Describe a visible posterior fat pad
Always ABNORMAL; it is a sensitive indicator of elbow trauma
Which fractures do child bones suffer and why?
Child bones are soft and so they bend/bow, rather than snapping and splintering; so they sustain:
• Buckle fracture (compression fracture on one side of a bone that causes the bone to bend or buckle toward the damaged side)
• Plastic bowing
• Greenstick fracture (incomplete fracture - one side of the bone is fractured and the other only bent)
Describe avulsion fractures in children
In children, it is common for ligaments/tendons to avulse their soft, bony attachments, e.g: the medial epicondyle of the humerus can be displaced by traction from the attached flexor tendons
Appearance of the physis?
AKA growth plate; seen as a lucency between the epiphysis and metaphysis that may stimulate a fracture
Injury of the physis?
Weakest part of a developing bone and so it is prone to injury, which can be complicated by growth deformity
Physes can look similar to fractures
Grading of growth plate fractures?
Salter-Harris classification is used, with 9 types
Describe non-accidental injury (NAI)
Femoral fractures of different ages indicate more than one injury
If a carer’s history does not fit the injury, suspect NAI
Bony ring fractures?
Rings are inherently strong structures; bones and joints often form rings to help share the transmission of force and increase strength, e.g: spinal canal, pelvis and forearm and lower leg
It is difficult to disrupt (fracture/dislocate) a ring in only one place, esp. where bone displacement is present; in other words, if a bony ring is injured, two or more disruptions WILL be seen
Appearance of foreign material on X-ray?
To be seen on an X-ray, foreign material must be different in density to surrounding tissues
In general, metal and glass can be seen but plastic and wood are often invisible
Pathological fractures?
Suspect when the bone abnormality seems out of proportion to the mechanism of injury, e.g: normal stresses on a weakened skeleton
Causes of a weakened skeleton?
Can be:
• Focal, e.g: a metastatic deposit causing a clavicle fracture
• Diffuse, e.g: due to osteoporosis or other metabolic bone disease
What is a Colles fracture?
Tends to occur in elderly patient with osteoporosis
Fracture of the distal radius in with dorsal (posterior) and radial displacement of the wrist and hand
How many carpal bones do children have?
8, as do adults, but only 4 are ossified and so only 4 can be seen on X-ray
What are scaphoid fractures?
Tend to be seen with young males; pain is felt in the anatomical snuffbox
Commonly occur at the mid-scaphoid
Prone to complications, like AVN
What are surgical neck of the humerus fractures?
Tend to occur in post-menopausal fractures and are often comminuted and can damage axillary nerve
Sclerosis indicates impaction
Upper limb injuries that are easily missed?
Posterior shoulder dislocation - if the humerus dislocates posteriorly, the lack of displacement makes it difficult to appreciate on an AP X-ray
Supracondylar fracture
Scaphoid fracture
Bennett’s fracture
How to see posterior shoulder dislocations?
An oblique view should be obtained, showing that the humeral head lies posterior to the articular surface of the glenoid
