Musculoskeletal Imaging Flashcards
What is the hard outer surface of bone that provides skeletal support and is the site of attachment for tendons and ligaments?
Cortical Bone
What is the “spongy”/trabeucular bone found at the ends of long bones, pelvis, ribs, skull, and vertebrae and contains red and yellow bone marrow?
Cancellous Bone
What does the Axial Skeleton consist of?
Bones of the Head and Trunk: Skull Bones Ossicles of Middle Ear Hyoid Bone Rib cage Sternum and Vertebral Column
What are the six regions of the appendicular skeleton?
Pectoral Girdles Arms and Forearms Hands Pelvis Thigh/Legs Feet/Ankles
What type of bone marrow are precursors to RBC’s? Where are they found after age 30?
Red Bone Marrow ; in the axial skeleton
What type of bone marrow contains fat and is found in the appendicular skeleton after 30?
Yellow Marrow
What are fibrous cords of tissue that attach muscles to bone?
Tendons
What are fibrous cords of tissue that attach bone to bone?
Ligaments
What is the best clinical guideline criteria recommended by Professor Smith?
The American College of Radiology Appropriateness Criteria
What is the initial imaging study of choice following skeletal trauma?
XRAY
What are xrays used to evaluate?
Cortical Integrity Articular Surface Congruity Joint Space Osseous lesions Bone Density (not as commonly used)
What questions should you ask when interpreting?
Trauma? Overuse Injury? Acute/Insidious Injury? Mechanism of Injury? General Health of Patient? Injury Pattern? Compare prior studies
What are three types of Mechanism of Injury?
FOOSH
Rotational Injury
Deceleration Injury
What are three types of Injury Patterns?
Traumatic/Atraumatic
High/Low Velocity
Acute/Chronic
The location and appearance of fracture depend on what three factors?
Mechanism of Injury
Age of the Patient
Predisposing Factors
What should you always do before getting an xray?
Examine the patient first
When ordering xrays, how many views should you order?
at least 2 orthogonal views; typically AP/Lateral
What should you do if a patient is symptomatic and high clinical suspicion of fracture but a negative xray?
Treat as fracture and splint
Have patient follow up with ortho in 7-10 days
Repeat xrays may show cortical changes
What is a comminuted fracture?
any fracture with more than 2 fragments
What types of fractures are the least common?
Spiral fractures
What is a butterfly Fracture?
subtype of comminuted fracture with wedge shaped fragment along the shaft of bone
When interpreting an xray what should you make sure is correct?
patients Name, gender, DOB Correct patient Correct date Correct region of Body part Correct side
What do you look for when interpreting an xray?
Open vs. Closed Anatomic Location Morphology of Fracture Line Displacement Distraction Angulation Rotation
What do most fractures appear as on xray?
radiolucent lines
Where is the most common site for Mach Bands?
ankle radiographs where tibia overlaps the fibia
What types of fractures appear as sclerotic fracture lines?
compression fractures
Where are sclerotic fracture lines most common?
vertebral bodies
Distal radius
Where is cortical buckling often seen?
distal radius
What are the three aspects of displacement?
Translation
Angulation
Rotation
What does translation (displacement) describe?
direction of translation of the distal fracture component compared to proximal
The amount of translation in %
What does the AP view show in regards to displacement?
medial to lateral displacement
What does the lateral view show in regards to displacement?
anterior to posterior displacement
What does angulation describe?
direction of angulation of distal facture component as compared to proximal
Amount of angulation in degrees
How is rotation seen easiest?
when looking at orientation of joints above and below fracture
What commonly causes distraction?
transverse fractures the results from tension force
What is distraction?
when a fracture is separated by a gap with no overlap
What is tension force and examples?
pulls or stretches two objects apart
medial malleolar and pattela fracture
What is alignment?
proximal femur fractures that are subtle and appear as misalignment of trabeculae across the femoral neck
What type of injury is most missed by inexperienced readers?
Anterior dislocation of 5th metacarpal base
What is impaction?
bones are wedged into each other
stable fracture
What is an avulsion fracture?
caused by abnormal tensile stress on ligaments of tendons and occurs at hands, feet, and pelvis
What is associated with dorsal distal phalanx avulsion?
extensor tendon
What is associated with base of fifth metatarsal avulsion?
peroneous brevis
What is associated with ischial tuberosity avulsion?
hamstring tendon
What helps in identifying an underlying fracture?
soft tissue swelling especially trauma to metacarpals and phalanges
What are joint effusions?
blood or inflammatory fluid or both near the joint which may be due to intra-articular injury to either the soft tissues or adjacent bone
Joint effusion in acute setting in patient with no underlying arthritis is presumptive sign of what?
hemarthrosis
What tendons should you check on a lateral ankle and lateral knee view?
quad and patella tendons
Achilles tendon
What may be present near ruptured tendons?
large effusions
What is beignet apposition?
comminuted fracture of the clavicle in which the distal end comes underneath the proximal end
What is normal to see in a shoulder xray?
the humerus head overlapping the glenoid
What two xray views help us to view how the shoulder is dislocated?
scapular Y and axial
What does the scapular Y view show if shoulder is dislocated?
the humeral head will be somewhere in the chest
What does an axial view show?
whether the shoulder is dislocated anteriorly or posteriorly
What is a proximal humerus fracture and how is it treated?
unstable fracture of the neck of the humerus
Treat with open reduction and internal fixation
What would be visible if the shoulder is dislocated anteriorly?
the corocoid process will protrude
Where do you see the Sail Sign and what does it suggest?
Sail Sign is seen on lateral view of elbow as fluid near joint
Suggests a radial head fracture
What is a common elbow fracture and its treatment?
Fracture of the lateral condyle of the humerus
treated by open reduction internal fixation
What does a Nightstick Fracture occur from?
Direct force on forearm; its a defensive injury
What is a Buckle Fracture known as (often seen on PANCE)?
Torus Fracture
What is a Colles Fracture?
fracture of the distal radial metaphysis with dorsal angulation and impaction
Common
Extra-articular
What is a Colles fracture caused by?
FOOSH
What type of fracture accounts for 10% of all fractures and 40% of hand fractures?
metacarpal fractures
What fractures make up 25% of all metacarpal fractures and 10% of hand fractures?
Fractures of 5th metacarpal which is usually the results of direct trauma
What is the treatment for 5th metacarpal fractures?
Nothing, they are stable and function will remain the same without treatment
What does SCFE stand for?
Slipped Capital Femoral Epiphysis
What causes a transverse distal femoral shaft fracture?
a high velocity injury like a motor vehicle crash or direct force
What is a transverse fracture?
fracture that is perpendicular to long axis of bone; stable fracture
What commonly causes a transverse fracture?
direct force or tension force
Where is a transverse fracture most common?
Forearm/leg
What is an oblique fracture?
inherently unstable fracture
What commonly causes an oblique fracture?
indirect forces
compression and angulation forces combine to cause shear force
How is an oblique fracture repaired?
In the OR
What type of fracture is least common?
Spiral Fracture
What creates a spiral fracture?
twisting movement through the long bone axis creating a rotation/shear forces
What type of fracture is a spiral fracture?
unstable and repaired in OR
What is a comminuted fracture?
fracture that has > 2 fragments
What type of fracture is a comminuted?
unstable that needs to be repaired in the OR
What side is a butterfly fragment produced on?
the concave, compression side
What causes a butterfly fragment?
indirect force producing a bending of bone with resultant tension vector on convex side and compression vector on concave side
What is a greenstick fracture?
incomplete fracture of long bone produced on convex cortex, while concave cortex becomes bent; without a visible grack
What side is a greenstick fracture on?
convex side
Where does a greenstick fracture usually occur?
in the forearm of young children
What causes a greenstick fracture?
bending force applied perpendicular to shaft
What is a Buckle/Torus Fracture?
type of incomplete fracture that occurs at metaphyseal diaphyseal junction
What causes a Buckle Fracture?
FOOSH
Is a buckle fracture stable or unstable
VERY STABLE and well heal more quickly than greenstick fracture
What is an avulsion fracture caused by?
abnormal tensile stress on ligaments/tendons
What is the most important Fracture Classification System that we need to know?
Salter-Harris System
What are Salter-Harris Fractures?
epiphyseal plate fractures in children typically 10-15 yrs old
Why are Salter-Harris fractures so important?
they can result in premature closure of growth plate and they represent 35% of all skeletal injuries in children
What is Salter Harris Type 1 fracture?
Fracture plane passes all the way through the growth plate, not involving bone
Cannot occur if growth plate is fused
What is the percentage of Type 1 SHF?
5-7%
What is the most common Salter Harris Fracture?
Type 2; 75%
What is a Salter Harris Type 2 Fracture?
Fracture passes across most of the growth plate and up through the metaphysis
Which Salter-Harris fractures have a good prognosis?
Type 1 and 2
What is a Type 3 Salter Harris Fracture?
fracture plane passes some distance along the growth plate and down through the epiphysis
What is the percentage of Type 3 SHF?
7-10%
What is a Salter Harris Type 4 fracture?
fracture is continuous through the metaphysis, physis, and epiphysis
What is the percentage of Type 4 SHF?
10%
What type of SHF has a poor prognosis because the proliferative and reserve zones are interrupted?
Type 4
What type of SHF has the worst prognosis?
Type 5
What is a type 5 SHF?
crushing type injury does not displace the growth plate but damages it by direct compression
What is the percentage of Type 5 SHF?
< 1%
What will you see in a SHF type 5?
several fractures within calcaneus
What helps to confirm a Type 5 SHF?
complete obliteration or diminished physeal distance of the affected extremity
What is the mnemonic for Salter Harris Fractures?
S = space A = above plate L = lower T = through R = really bad
