imaging of upper limb Flashcards
To remember before all else
- always identify
- type of imaging modality
- plane (coronal, sagittal, axial OR longitudinal/transverse)
- sequences and windows where relevant (e.g. fluid-weighted fat saturated MRI, include windows here!)
- region imaged
- inform superiors of
- open vs closed fracture
- neurovascular status: is there a pulse? is there paraesthesia or numbness?
- if it looks like a fracture and feels like a fracture but you can’t see a fracture, treat it as a fracture and follow-up after 1 wk with same or different modality of imaging
- e.g. resorption at fracture ends can make it more ] visible on follow-up XR
- take an image from a minimum of two planes (e.g. AP and lateral, and maybe oblique)
What are the relevant imaging modalities for the upper limb
- XR -
- US
- MRI -availability low in ED, second line
Consider CT for arthritis.
Nuclear medicine to rule out cancer.
How to report iamges for upper limb per modality
There are several features that should always be mentioned when reporting images of the spine:
- XR: projection (frontal: AP/PA, lateral, oblique]); plane; region imaged; patient details: rotation, quality, exposure, non-organic objects; identify normal and abnormal structure
- US: x; plane; region imaged; patient details: quality and exposure, inorganic objects; normal and abnormal structures
- MRI: imaging modality (—-); plane; region imaged; contrast vs no contrast; patient details: quality and exposure, inorganic objects; normal and abnormal structures
What are teh requirements of Xray iamging?
- X-Radiography of the upper limb is not just about the bones; soft tissue planes and gas presence are also crucial.
- For elbow effusion indicating an underlying fracture, a minimum of two views at right angles (AP and Lateral) is essential.
- The importance of AP (Anterior-Posterior) and PA (Posterior-Anterior) views in diagnosing fractures.
What is the appearance of structures on XR?
- air is black (radiolucent), as are cysts ^[OA]
- fat is dark grey
- soft tissue is grey
- bone is off white, as are osteophytes, sclerosis
- metal is white (radioopaque), as are effusions
What structures must you be able to identify on XR?
Frontal Shoulder
- clavicle
- conoid tubercle
- lateral and medial ends
- scapula
- superior angle
- inferior angle
- spine
- acromion
- coracoid
- glenoid fossa
- lateral and medial borders
- humerus
- head
- neck
- shaft
- surgical neck
- intertubercular sulcus
- greater and lesser tuberosity
- ribs
- AC joint
- GH joint
![[Pasted image 20240209150519.png]]
Lateral shoulder:
- clavicle
- lateral end
- conoid tubercle
- scapula: looks like a Y
- inferior angle
- spine
- acronmion
- coracoid
- humerus
- head
- necks
- shaft
- greater nad lesser tub
- ribs
- AC joint
- GH joint
- ![[Pasted image 20240209150530.png]]
Elbow frontal: - humerus
- shaft
- medial and lateral epicondyles
- medial and lateral supracondylar ridges
- capitulum
- trochlea
- olecranon fossa
- radius
- head
- neck
- shaft
- radial tuberosity
- ulna
- shaft
- olecranon
- coronoid
- ![[Pasted image 20240209150614.png]]
Elbow lateral - anterior fat pad
- humerus
- shaft
- superimposed supracondylar ridge
- capitulum
- trochlea
- radous
- head
- neck
- shaft
- radial tub
- ulna
- olecranon
- coronoid
- shaft
- ![[Pasted image 20240209150623.png]]
Hand frontal: - radius
- styloid
- shaft
- ulna
- styloid
- shaft
- carpals
- metacarpals; phalanges and sesamoids where visible
- ![[Pasted image 20240209150632.png]]
- ![[Pasted image 20240209150639.png]]
- ![[Pasted image 20240209150647.png]]
- ## ![[Pasted image 20240209150655.png]]
Describe teh usage of ultrasound
US is used to better visualise the soft tissue structures surrounding the joints of the upper limb.
- Ultrasound allows for dynamic assessment of structures in the upper limb. This affords ultrasound a unique place in radiology over static imaging (i.e. x-ray, CT, MRI).
- Some examples of dynamic imaging include assessment of the ulnar nerve during elbow extension and flexion (looking for nerve subluxation), focal tenderness (a sign of inflammation over a bursa/tendon/ligament), reproduction of neurology (e.g. median nerve symptoms during compression of the nerve in the carpal tunnel space), or observing normal glide/movement of a tendon during flexion and extension (e.g. trigger finger).
- Scan planes are best thought of as transverse/axial, sagittal or longitudinal to the structure of interest (typically this will be labelled for you).
- Remember that the shape of the top of the image is usually indicative of the probe used (e.g. linear, curvilinear), with the most superficial structure at the top of the image.
- Upper limb ultrasound for soft tissue injuries and scaphoid fractures.
Describe the appearance of structures on ultrasound
Recall that structures may be hyperechoic (light grey) or hypoechoic (dark grey or black).
- bone - hypoechoic with defined margins
- fat - hyperechoic
- muscles- hypoechoic with “hyper-echoic speckles” : starry night appearance
- tendons - hyperechoic and fibrillar : hypoechoic when torn
- fluid - anechoic/hypoechoic
- skin- hyperechoic, faded grey
What structures must be identified on XR?
GC and AC joints:
- cortical bone: greater and lesser tuberosities, humeral head
- long head of biceps tendin
- rotator cuff tendon
- skin
- subcutaneous fat
- deltoid muscle
- SASD bursa: deep to deltoid, superficial to cuff tendons
![[Pasted image 20240218173321.png]]
![[Pasted image 20240218173350.png]]
Elbow:
- CEO
- lateral epicondule
- radial head
- dermis
- triceps tendon
- olecranon
- trochlea
List and describe uses of MRI
- MRI is the most sensitive test for undisplaced fractures.
Note also that scan planes are typically not going to be orthogonal to the whole body, but rather, the axial/transverse, sagittal, and coronal planes will be centred on a structure of interest (e.g. bone, joint, tendon, ligament).
Describe appearance of structures on MRI
Fluid weighted, non-fat saturated:
- fluid appears white
- fat appears light grey
- muscles are grey
- bones are white
Fat saturated:
- fat appears dark
- fluid still appears white
- muscles are grey
- bones are black
List structures to identify on MRI
Elbow (depends on projection):
- CEO
- triceps tendon
- olecranon
- olecranon fossa
- coracoid process
- trochlea
- capitulum
- CFO
GH:
- head
- acromion
- coracoid
- rotator cuff muscles
- glenoid process
- biceps brachii tendon
Frontal hand:
- carpals
- metacarpals
Axial wrist:
- extensor compartments
- listers tubercle
- carpal tunnel components including median nerve
