Musculoskeletal Imaging Flashcards
What is the purpose of cortical bone?
What is the purpose of cancellous bone?
Cortical: “hard” outer surface provides skeletal support and is site of attachment for tendons and ligaments
Cancellous: “spongy”/trabecular bone, found at ends of long bones pelvis ribs, skull and vertebrae (contains red/yellow bone marrow)
Axial skeleton consists of what two things?
What are the six parts of those two things?
-Consists of bones of head and trunk Six parts: -skull bones -ossicles of middle ear -hyoid bone -rib cage -sternum and vertebral column
Appendicular skeleton is divided into six major regions what are they?
-Pectoral girdles → clavicles and scapulae -Arms and forearms -Hands -Pelvis -Thighs/legs -Feet/ankles
Red marrow:
- ) What does it produce?
- ) At age 30 it is best seen?
1.) produces precursors of RBC’s
2.) Axial skeleton
-Consists of bones of head and trunk
Six parts:
-skull bones
-ossicles of middle ear
-hyoid bone
-rib cage
-sternum and vertebral column
Yellow Marrow:
- ) What does it contain?
- ) At age 30 it is best seen?
1.) Contains fat
2.) best seen in appendicular skeleton
-Pectoral girdles
→ clavicles and scapulae
-Arms and forearms
-Hands
-Pelvis
-Thighs/legs
-Feet/ankles
What is the epiphyseal line ?
Where growth in a long bone takes place
The metaphysis is the ?
The diaphysis is the?
The epiphysis is the?
1.) M= End of bones
→ The metaphysis is the narrow portion of a long bone between the epiphysis and the diaphysis. It contains the growth plate, the part of the bone that grows during childhood, and as it grows it ossifies near the diaphysis and the epiphyses.
- ) D=mid shaft of bone
- ) E=articular cartilage at the end of all long bones
Why do breaks usually occur at the ends of bones and not in the middle
because the cortical bone is the thickest mid-shaft b/c it supports most of our weight
Tendons attach?
Ligaments attach?
muscle to bone
L: bone to bone
Where do you go to look up the clinical guidelines to help you determine what right choice the best choice of “image testing” for your patient?
The American college of radiology (ACR) appropiateness criteria
X-rays are the initial imaging study of choice following skeletal trauma. They are used to evaluate?
- Cortical integrity
- Articular surface congruity
- Joint space lesion
- Osseous Lesion
CT Scan:
1.) CT scan is better than X-ray in?
2.) It is the imaging study of choice for?
- )
- Visualizing articular fracture extension**
- Assessing for presence of articular step-off/gap
- Evaluating aortic injuries in chest trauma - )
- Imaging study of choice in abdominal trauma
MRI:
- ) MRI’s are the cornerstone of ?
- ) MRI’s are very helpful in evaluating ?
- ) MRI are better than x-ray and CT in ?
- ) MRI’s are the modality of choice for?
1.) Cornerstone of neuroimaging
2.) very helpful in soft tissue evaluation such as
→Tendons
→Muscles
→Ligaments
3.) MRI are better than x-ray and CT in identifying occult fractures
- )MRI’s are the modality of choice for
- Disc herniation
- to assess “internal derangement” of joints
ex: ACL tear
- ) Ultra sound is commonly used in what type of setting?
2. ) In this “setting” it is used to asses?
1.) trauma setting
2.) Soft tissue injury
→ Achilles’ tendon rupture
→ quad tendon rupture
What is the most important musculoskeletal evaluation that you can preform?
Taking a patients medical history is the most important in musculoskeletal evaluation
The location and appearance of fracture depend on various factors, they are?
-Mechanism of injury
→ indirect force or direct force
-Age of patient
→ elderly or child
-Predisposing Factors
→ Osteoporosis
→ Osseous lesion
→ Trauma
- ) In 5% of fractures, fracture line is only visualized on
- ) In another 5 %, fracture line is only visualized on an?
- ) one of two orthogonal projections (Ex: AP vs. PA)
2. ) oblique (non-AP or lateral) projection
- ) If a patient has Ankle pain, do not order?
2. ) Instead you should order?
- ) tib-fib view
2. ) Order a 3-view Ankle series
A patient is symptomatic and highly suspect that there is a fracture even though their X-ray is negative. What should you do as a provider ?
- Treat as fracture and splint
- have patient follow up with ortho in 7-10 days
- repeat x-rays may show cortical changes
What are the steps for interpreting an X-ray? (3 steps)
1.) Make sure you have the correct patients name, gender, and DOB
- ) Make sure you have the correct region of the body
(ex: if you want an ankle x-ray don’t order tip-fib view)
3.) Is the X-ray taken of the correct affected side of the body? (Left vs. right)
- ) Most fractures lines appear ?
2. ) What does the Lucent line look like in non-displayed fractures ? So this means you will need?
- ) most fractures lines appear as a radiolucent line
- ) In non displaced fractures, Lucent lines are thin and maybe difficult to appreciate so you need two orthogonal views
- ) What are Mach bands?
2. ) What is the most common site to find them?
1.) appear at sites of cortex that overlap between two bones, or skin fold overlap of the cortex
- ) What are Mach bands?
2. ) What is the most common site to find them?
- ) appear at sites of cortex that overlap between two bones, or skin fold overlap of the cortex
- ) ankle radiographs→ were tibia overlaps fibula
Compression fractures may appear as ?
sclerotic fracture lines
Most common locations for sclerotic fracture lines are?
- ) vertebral bodies
2. ) distal radius
Cortical Buckling
- ) Cortical Buckling is seen in the absence of?
- ) Cortical buckling is most often seen at the ?
- ) Cortical buckling fractures look like?
- ) It is important to inspect all other projections because cortical buckling fractures can only be seen?
- ) • Cortical Buckling is seen in the absence of fracture line
- ) Often seen in the distal radius metaphysis (often seen in children)
- ) look like jagged edge or ramp
- ) May only be seen on one view, important to carefully inspect all projections
- ) Intra-articular extension fractures can be seen..?
2. ) These types of fractures can be
- ) Fractures can seen extending into the joint space (Lucent line goes right into joint space)
- ) ↑ risk of post-traumatic arthritis
1.) What are the three types of displacements?
2.) How would you describe displacement?
2 criteria steps
1.)
• Displacement
• Angulation
• Rotation
- )
a. direction of translation of DISTAL fracture component compared to PROXIMAL
b. the amount of translation (as percentage of bone width-in quartiles (25%, 50% etc.)
How would you describe angulation?
2.) What is important when assessing angulation?
1.) Describe direction of angulation of distal fracture component compared to proximal
→ ex: distal fragment is angulated to proximal fragment (lateral angulation)
2.) Important to use two orthogonal views to describe
- ) Rotation is describe as ?
- ) Why is a rotated fracture important to fix?
- ) how many views is it important to get?
- ) Turning of the distal fracture fragment in relation to proximal portion
* ** important to get two views
2.) Rotation very important to correct as anatomic alignment of bone critical to normal function
- ) Rotation is describe as ?
- ) Why is a rotated fracture important to fix?
- ) how many views is it important to get?
- ) Turning of the distal fracture fragment in relation to proximal portion
* ** important to get two views
2.) Rotation very important to correct as anatomic alignment of bone critical to normal function
Distraction fracture is described as ?
It is commonly seen with?
ex:
- fracture separated by a gap with no overlap
- common with transverse fracture that result from tension force
Ex: medial malleolar and patella fracture
→ quad muscle can spasm and pull patella up
How does tension force cause a distraction fracture?
because it pulls or stretches two objects apart
CMC joint alignment is an important check area when assessing?
hand wrist x-rays
- ) Impaction fracture can be describe as?
2. ) Is an impaction fracture Stable or Unstable ?
Impaction:
• When bones are wedged into each other (shortening with no loss of bone alignment)
• Stable fracture
Avulsion fractures occur when?
Fragment of bone is pulled off via ligament or tendon tensile strength
Where can avulsion fractures occur?
- hands: dorsal distal phalanx with extensor tendon avulsion
- Feet: base of fifth metatarsal with peroneus brevis avulsion
- Pelvis: ischial tuberosity with hamstring tendon avulsion
Soft tissue swelling is helpful in ?
identify an underlying fracture
Especially helpful when assessing trauma to the metacarpals or phalanges
- ) Joint effusion in acute setting in patient with no underlying arthritis is presumptive sign of
- ) In chronic setting of joint effusion you can think?
hemarthrosis (blood in joint space)
2.) inflammation
What is the Sail sign?
What does it indicated in adults? children?
The anterior fat pad is usually concealed within the coronoid fossa or seen paralleling the anterior humeral line. When there is a joint effusion, the anterior fat pad (which is intra-articular, but extrasynovial) becomes elevated due to the effusion pushing it out.
Elevation of the anterior fat pad usually heralds the presence of an intra-articular fracture. In adults, this is usually a radial head fracture whereas in children, the commonest cause of a raised elbow fat pad is a supracondylar fracture.
Interpreting the X-ray in Summation?
What are in order the seven ways of describing a fracture?
- Open vs Closed
- Anatomic location
- Which bone?
- Left/Right
- Midshaft; proximal metaphyseal- diaphyseal junction
• Morphology of fracture line
- transverse; oblique
- Intra-articular?
• Displacement
- Described in percentage %
• Angulation
- dorsal; (non palm side of hand)
- volar (palmar)
-varus;
-valgus
(The opposite of varus is called valgus. … The terms varus and valgus always refer to the direction that the distal segment of the joint points. For example, in a valgus deformity of the knee, the distal part of the leg below the knee is deviated outward, in relation to the femur, resulting in a knock-kneed appearance.)
- Rotation
- Distraction
Transverse Fracture:
1.) Presenation?
- ) Commonly caused by?
- ) Commonly occurs in?
1.) perpendicular to long axis of bone
2.) commonly caused by direct force (most common in forearm/leg)
→ can be displaced
Oblique fracture:
1.) Presentation?
- ) Commonly caused by ?
- ) Oblique fractures are prone to ?
- ) Treatment?
- ) Fracture that occurs at an angle
- ) Commonly caused by indirect force
- ) Prone to angulation in plane of fracture
- ) generally repaired in OR
Spiral fracture:
1.) presentation?
- ) occur due to ?
- ) Treatment?
- ) Are they common or uncommon?
- ) complete fracture of long bones as a result of rotational force
- ) created as a result of rotational force( twisting movement through long bone axis)
- ) repaired in OR
- ) uncommon
Comminuted Fracture:
1.) Described as ?
- ) Treatment?
- ) Severity made be graded as ?
1.) • Contains >2 fracture fragments
2.) • Inherently unstable fracture
→ Generally repaired in OR
3.) Severity made be graded as:
• Minimal: small fx fragments next to larger fx line
• Moderate to severe: several large fragments
Butterfly Fragment:
1.) Presentation?
2.) Occurs due to ?
1.) Butterfly fragment produced along concave, compression side.
- ) Indirect Force produces bending of bone resulting in
- tension vector on convex side
- compression vector on concave side
Green Stick fracture:
1.) Presentation?
- ) Usually occurs in ?
- ) This fracture occurs because
- )
- Incomplete fracture of long bone produced on convex cortex side
- Concave cortex becomes bent BUT WITHOUT VISBLE CRACK - ) Forearm of young child
- ) occurs because of a bending force applied perpendicular to shaft
Torus (buckle) fracture
- ) It is a type of ?
- ) Typically occurs in what part of the body?
- ) Is it stable or unstable?
- ) occur most often in what age group?
1.) type of incomplete fracture
2.) Typically occurs at
metaphyseal-diaphsyeal junction after FOOSH
3.) Very stable fracture
→ Tend to heal more quickly than greenstick fractures
likes
4.) kids
AC Joint X-ray views?
AP with and without weights
Chest X-ray views?
PA
Lateral (full inspiration)
Clavicle X-ray views?
AP
Axial (20 deg cephalad)
Humerus X-ray views?
AP
Lateral
SC Joint X-ray views?
AP
Obliques (bilateral)
Shoulder X-ray views?
AP
Grashey
Y-scapular view (good view for finding dislocations)
Where are fractures usually found in the clavicle ?
Where do you start your observation when assessing a clavicular fracture?
- ) Mid shaft- b/c its most narrow for clavicle
2. ) start at sternoclavicular joint
Olecranon fracture:
1.) Are common in what age groups?
2.) direct blow vs. Indirect blow
1.) high energy in young
low energy in elderly
- )
- direct blow: → comminuted fracture of olecranon
- indirect blow: → transverse or oblique fracture
Proximal displacement of olecranon is due to ?
treatment?
- ) triceps tendon pulling fracture upwards
2. ) treated by open reduction internal fixation
- ) Both bone forearm fractures occur more commonly in men or women?
- ) Can occur because pt was ?
Men
2.) protecting their head
Ratio of open to closed fractures is higher than for any other bone except
tibia
Nightstick fracture:
1.) occur where in the bone?
results in direct force to the ulna
Colles fracture
- ) presentation?
- ) result of ?
1.) extra-articular fracture of distal radial metaphysis with dorsal angulation and impaction
Smith fracture
- ) presentation?
- ) result of ?
- ) why is this fracture important?
1.) Fracture of distal radius with associated volar angulation of distal fracture fragment
→ Extra-articular transverse fractures
→ AKA reverse Colles fracture
2.) Mechanism
• Fall onto a flexed wrist
• Direct blow to the back of the wrist
3.) worse than colles fracture check for pulse
Elbow x-ray views?
AP,
lateral
external oblique
Fingers x-ray views?
AP
Lateral of affected finger
Oblique of hand
Hand x-ray views?
AP
Lateral
Oblique
Thumb x-ray views?
AP
Lateral
Oblique
Wrist x-ray views?
AP
Lateral Oblique
Fractures of 5th metacarpal make up what % of all fractures?
Fractures of metacarpal in general make up what % of hand fractures
- 25%
- 40%
X-ray views for Hip?
AP
Pelvis
Frog Lateral
Ankle X-ray views?
AP
Mortise
Lateral
Femur X-ray views?
AP
Lateral
Foot X-ray views?
AP
Oblique
Lateral
Knee X-ray views?
AP
Lateral
Tunnel
Merchant
Tib-fib X-ray views?
AP
Lateral
Heel X-ray views?
Axial
Lateral calcaneus
For a femoral neck fracture what is the treatment?
hemiarthroplasty (replacing the head)
Slipped Capital Femoral Epiphysis (SCFE)
What is a SCFE?
Head of femur has slipped off neck of femur
What is a fatal fracture that can occur in the leg that you can’t miss?
Transverse distal femoral shaft fracture
When view is used to see if there is arthritis of the knee?
Rosenberg view (45 deg flexion, posterioanterior, WB view of knee
Exam of ankle fracture should start at?
knee
Maisonneuve Fracture is ?
Combo of spiral fracture in proximal fibula with ankle injury of one or more:
• widening of ankle joint due to distal tibiofibular syndesmosis
• deltoid ligament disruption
• fracture of the medial malleolus
If there is a calcaneus fracture seen you then need to evaluate for and order what?
evaluate spine for compression fracture and order lumbar-spine films