Injury Imaging Flashcards
What are the standard projection for shoulder imaging?
Anterior-posterior (AP) External Rotation
AP Internal Rotation
What are the additional projections for shoulder imaging?
Axillary view
Scapular Y lateral view
What are the projections for AC joint imaging?
AP
Bilateral (with and without weights)
What are the projections for scapular imaging?
AP
Lateral
What does the shoulder AP external rotation imaging demonstrate?
Proximal 1/3 of humerus
Lateral 2/3 of clavicle
AC joint
Upper and lateral portion of the scapula
What are the key observations for AP external rotation shoulder imaging?
Greater tuberosity and lesser tuberosity (superimposed at mid-area of humeral head)
Medial portion of humeral head (partially superimposed in glenoid fossa)
Crest of spine of scapula
Superimposition of scapula behind rib cage
What should the width of the GH joint be?
5mm; note for increase or decrease
Which joint is superior to GH?
AC
What structural abnormalities should be observed for in AP External rotation view?
Increase in superimposition of humeral head; subluxation, dislocation
Decrease in superimposition of hmeral head; DJD
AC joint DJD, subluxation, dislocation
Calcium deposits in muscles, tendons or bursae
What does AP internal rotation demonstrate?
Proximal 1/3 of humerus
Lateral 2/3 of clavicle
AC joint
Upper and lateral portion of scapula
What are the key observations of AP internal rotation?
Greater tuberosity now superimposed over mid-area of humeral head
Lesser tuberosity seen in profile on the medial aspect of the HoH
Medial portion of humeral head partially superimposed in glenoid fossa
Crest of spine of scapula
Superimposition of scapula behind rib cage
Observe for calcium deposits in muscles, tendons, bursae
What structures are ossified at birth?
Only the clavicle, scapular body, humeral shaft and proximal humeral head are ossified
What ossification centres appear between the ages of 3-5 in the shoulder?
Greater and lesser tuberosities
What shape are the growth plates in paediatrics?
Cone shaped with apex pointed superiorly
What occurs at 16 years old in the shoulder?
Greater tuberosity fuses with humeral shaft
When does complete fusion occur?
20-22 years
What is the ossification process of the scapula from birth?
Coracoid process ossification centre appears at 1 year
Other scap structures at puberty
Fusion with rest of scap at 18-25
What does an axillary shoulder view demonstrate?
Inferosuperior axial projection of the GH joint
Exact relationship of humeral head to glenoid fossa
Esp. useful in evluation of GH dislocations
Rims of the glenoid fossa and coracoid process
What does the bilateral with and without weights demonstrate?
Bilateral AC joints for compression
Weights are added for a stress view to visualise instability
Entire length of clavicles
Both SC joints
Both shoulders in AP view
What are key observations in bilateral with and without weight views?
Assess AC joint space and coracoclavicular distance
What is visible with a grade 1 AC sprain?
Mild = minimal widening of AC joint space; coracoclaivular distance still within normal range
What is visible with a grade 2 AC sprain?
Moderate = widening of AC joint space to 1-1.5 cm with a 25-50% increase in coracoclavicular distance still within normal range
What is visible with a grade 3 AC sprain?
Severe = widening of AC joint space > 1.5cm with >50% increase in coracoclavicular distance
What are the main AC joint mechanisms?
Direct blow
Traction on arm
FOOSH
Fall on flexed elbow
What may AC joint injuries be complicated by?
Fracture of clavicle
Acromion
Coracoid
What is the most common cause of proximal humerus fracture?
FOOSH - esp. older women
High energy trauma in younger adults
What is the most common cause of clavicle fracture?
-75% occur in children
FOOSH accounts for majority
Childbirth trauma
Athletes = stress fracture
What are the standard wrist projections?
PA
Lateral
Oblique
What are the optional wrist projections?
Radial and ulnar deviation
What are the standard hand projections?
PA
Lateral
Oblique
What does a PA wrist view demonstrate?
Middle and proximal portions of metacarpals
Carpal bones
Distal radius and ulnar
Related joints
What are key observations in PA wrist?
Three arcuate line drawn outlining distal carpals
Subluxation and dislocation
Scaphoid, lunate, capitate and hamate - relatively free from superimposition
Trapezium, trapezoid, triquetrum and pisiform are superimposed
What are the 3 observations for a PA wrist image?
1 = proximal surfaces of scaphoid, lunate, triquetrum
2 = distal surfaces of scaphoid, lunate, triquetrum
3 = proximal margins of capitate and hamate
What hand and wrist structures are ossified at birth?
Shafts of the MCs and phalanges
What occurs for infants between the ages of 6 months and 6 years for the wrist and hand?
Ossification of most carpals begin
Pisiform ossification complete by age 14-16
At what age are the MCs and phalanges completely fused by?
16-18 years
When do secondary ossification centres appear in the epiphyses of MCs and phalanges?
2 years
What are the structures demonstrated by a lateral wrist image?
Proximal metacarpals
Carpals
Distal radius
Ulna
What are the key observations of a lateral wrist imaging?
Alignment of longitudinal axes of radius, lunate, capitate and third metacarpal “stacked arrangement”
Despite superimposition, displacement of # fragments can be easily detected in a dorsal or palmer direction
When are the radial and ulnar shafts fully fused by?
18-20 years
What does an oblique view of the wrist demonstrate?
Middle and proximal metacarpals
Carpals
Distal radius and ulna
What structures are best shown on an oblique wrist image?
Trapezium
Scaphoid
First CMC joint of the thumb
What are the key observations of the oblique wrist imaging?
1st and 2nd metacarpals viewed with minimal superimposition
Proximal portions of 3rd, 4th and 5th metacarpals
Distal radius and ulna are slightly superimposed
Styloid processes of both are well visualised
Which carpals are well demonstrated in an oblique wrist view?
Hamate - body and hook
Triquetrum - dorsal aspect
Trapezium and its articulation with the trapezoid, scaphoid and 1st metacarpal
What does a radial deviation image demonstrate?
Ulnar side carpals best shown (lunate, triquetrum, hamate, pisiform)
Adjacent opened ulnar intercarpal spaces
What does a ulnar deviation image demonstrate?
Scaphoid and adjacent opened radial intercarpal spaces
Scaphoid normally appears elongated in this view due to rotation of distal pole towards ulna due to intact ligaments
Elongated appearance verifies normal articulation to adjacent carpals
This view may help identify subtle scaphoid #
What does a PA hand view demonstrate?
Hand, wrist and distal forearm
Structures best shown are the phalanges, metacarpals, carpals and joints of the hand
What are the key observations of a PA hand image for the shafts and metacarpals?
Symmetrical appearance of the terminal ends of distal phalanges
What is a normal appearance for ends of distal phalanges?
Tufted appearance
What joint spaces are visible in a PA view?
Interphalangeal and metacarpophalangeal joint spaces
Where are sesamoid bones commonly found in PA hand views?
MCP and IP joints of the thumb and the MCP joint of the 5th finger
What bases overlap on a PA hand view?
Bases of 2nd and 5th MCs
What does a lateral hand view demonstrate?
Hand and wrist
Thumb is seen in true PA projection
+/- sesamoid bones
What are the key observations in a lateral hand view?
Phalanges and emtacarpals are superimposed
Most of the carpals, the distal radius and ulna are also superimposed
Observe for disaplced fracture fragments - can be in a dorsal or palmar direction
Stacked appearance of the radius, lunate and capitate
Longitudinal axes of the radius and lunate should be in alignment - observe for rotation of the lunate which suggests instability
What does an oblique hand view demonstrate?
Phalanges
Metacarpals
Carpals
All joints of the hand
What are the key observations in an oblique hand view?
Phalanges and metacarpals are demonstrated without superimposition
An advantage of the oblique view vs lateral view
Lateral is best for visualising displacement
Interphalangeal and MCP joint spaces are visible
