Introduction to musculoskeletal radiology (banks) Flashcards
Several diagnostic modalities can be used to evaluate musculoskeletal disorders:
X- Rays, CT and DXA* use ionizing radiation*.
Ultrasound uses high frequency ultrasound waves.
Nuclear Medicine uses gamma rays from isotopes.
MRI uses high magnetic field strength.
- DXA (Dual energy X-ray Absorptiometry) uses a small dose of ionizing radiation to measure bone loss.
- Ionizing radiation and gamma rays - form of high energy capable of removing electrons from an atom or molecule of
General Trauma Workup
Start with X-rays, 3 views of the area of concern should be obtained: anterior, lateral and oblique.
To improve sensitivity for subtle/occult fractures, consider contralateral radiographs or more advanced imaging such as a CT or MRI.
identify and mechanism
Clavicle fracture
Mechanism of fracture: direct blow to the clavicle
Fracture is most common in the middle portion of the clavicle (65-80%)
Identify ligaments
Identify and mechanism
Mechanism of AC joint injury:
Fall onto the shoulder
Falling on the outstretched hand (FOOSH)
Classification of AC joint injury:
Types 1-3: Treatment is medical
Types 4-6: Rare/Treatment is surgical
Normal Shoulder
The humeral head sits in the middle of the scapula, over the glenoid process.
If the humeral head is under the coracoid process, this is an anterior shoulder dislocation
If the humeral head is under the acromial process this is a posterior shoulder dislocation.
Anterior shoulder dislocation
Posterior shoulder dislocation
Light bulb sign: internally rotates with posterior dislocation
Trough sign: fx of medial anterior head of humerus, see 2 parallel cortical lines medially indicates a compression fx
Calcification in the supraspinatus tendon
Degenerative joint disease (DJD)
shoulder impingement with disruption of suprasinatus tendon
Humeral shaft fracture
Medial displacement of proximal fragment by the pulling force of the pectoralis major and teres major muscles.
Elbow fractures
Most common area in adults is a fracture in radial head/neck
Second most common is in the olecranon process
Mechanism: F O O S H, or direct fall on flexed elbow
Can be associated with dislocation
Elbow pain; FOOSH
anterior displacement of the anterior fat and and visualization of the posterior fat pad indicates elbow joint effusion. In a setting of trauma, the cause would be fracture
Fat pad “sail sign”
Olecranon process fracture
elbow posterior fracture dislocation
X- Ray of the Hand and Wrist
The most commonly injured body part is the hand
The hand has 27 bones and 29 major joints
In most cases, X-Rays are sufficient
8% of hand fractures are multiple, so look for additional fractures
Distal Radius fracture
1/6th of all fractures in the emergency department are distal radial fractures
Mechanism: F O O S H
Scaphoid fracture Most commonly fractured carpal bone, anatomic “snuff box” Location: Waist: 65% Proximal: 25% Distal third: 10% Incidence of avascular necrosis (AVN): 13 – 40% (post traumatic) Almost all in proximal pole to due to limited blood supply
scaphoid fractures
Boxer fracture
a distal metacarpal fracture that usually invokes the fish metacarpal
Proximal femoral fractures
- femoral neck
- intertrochanteric
- subtrochanteric
Femoral neck fracture
Complication: A V N is more common with intracapsular fractures than with extracapsular fractures
occult fracture
X- ray insensitive for hip fracture
Especially in elderly with osteoporosis
Fracture incomplete or nondisplaced
10% of femoral fractures are occult on X-ray, CT is 85% sensitive, and MRI is almost 100% sensitive
occult fracture in the hip
proximal femoral intertrochanteric fractures
supracondylar fracture
Intercondylar fracture of the knee
knee dislocation
tibial plateau fracture
MCL calcification (pellegrini-sieda) calcification is secondary to old trauma to MCL and/or medical femoral condyle
(anterior cruciate ligament) ACL tear causes displacement of the tibia anteriorly (anterior drawer sign)
ACL tear, MRI of the knee;
posterior cruciate ligament PCL tear causes displacement of the tibia posteriorly (posterior drawer sign)
calcaneal spur
fhl: flexor hallucis longus
a: Achilles tendon
Black arrows: Plantar aponeurosis, rises from the calcaneus. Plantar fasciitis- inflammation of the plantar aponeurosis (fascia).
sesamoid/bone
flexor hallucis longus tendon inserts on the plantar aspect of the base of the distal phalanx of the great toe, after traveling between the two sesamoids
achilles tendon tear
achilles tendon tear
compare different radiographic modalities
