Scaphoid, Forearm and Elbow Flashcards
When working with angles what must you check?
The SID
What is the scaphoid?
- the largest carpal in the proximal row
- anterior and lateral tubercles
- palpable near the base of the thumb
- “anatomical snuffbox”
What is the carpal canal?
- bony passageway for the median nerve and flexor tendons to pass through
- goes through the carpals and the flexor retinaculum
- compression of the median nerve causes carpal tunnel syndrome
What is the elbow?
- articulation of the humerus with the radius and ulna
- distal humerus has two condyles (trochlea and capitulum)
- epicondyles are the medial and lateral protuberances above
- distal humerus has 2 fossae (olecranon and coronoid)
- 2 fat pads seen on the lateral projection
Scaphoid - PA Projection
position - hand prone in ulnar deviation
CR - perpendicular to IR
CP - scaphoid
collimation - base of 1st metacarpal to ulnar head
Scaphoid - PA Axial Projection
Position - hand prone in ulnar deviation
CR - 20 degrees proximally
CP - Scaphoid
collimation - base of 1st metacarpal to ulnar head
Scaphoid - Alternate PA Axial Projection
Position - hand prone in ulnar deviation - hand elevated on a 20 degree sponge
CR - perpendicular to IR
CP - Scaphoid
collimation - base of 1st metacarpal to ulnar head
Scaphoid - PA and PA Axial Evaluation Criteria
- distal radius and ulna to proximal half of meta carpals
- scaphoid and adjacent joint spaces open
- axial method should show scaphoid freer from superimposition
- no rotation
- ulnar deviation
- see boney trabeculae and soft tissue
What is the scaphoid series?
Rafert-Long method
4 images
PA and PA axial with angles of 10, 20 and 30
Tangential carpal canal projection
- hyperextend wrist
- slight radial rotation (flattens carpal canal)
CR - 25-30 proximally
CP - Palm of the hand, include all of the canal - styloids to centre of IR
Tangential carpal canal evaluation criteria
- carpals are in an arch
- pisiform separate and in profile
- hook of hamate
- common athletic injuries can be diagnosed with this projection: hook of hamate, pisiform and trapezium
Forearm - AP Projection
3 major joints must be on the same plane (wrist, elbow and shoulder)
- arm supinated, ensure elbow and wrist are true AP - epicondyles equidistant
CR - perpendicular
CP - middle of forearm
collimate 5cm or 2in past each joint
Forearm - AP Evaluation Criteria
- entire forearm and both end joints
- slight superimposition of proximal radius/ulna
- no elongation/foreshadowing of humeral epicondyles
- partially open wrist and elbow joints
- open radioulnar space
Forearm - lateral projection
3 joints on same plane, arm bent 90, wrist and lateral in true lateral best you can
CR - perpendicular
CP - middle of forearm
Collimate 5cm or 2in past each joint
Forearm - lateral evaluation criteria
- entire forearm and both end joints
- superimposition of distal radius/ulna
- superimposition of radial head and coronoid process
- superimposed humeral epicondyles
- radial tuberosity facing anteriorly
What projections do you start hanging in anatomical position?
elbow
Elbow - AP projection
3 joints on same plane
hand supinated, epicondyles equidistant to IR
CR - Perpendicular
CP - middle of elbow
collimate 8cm or 3in on either side of joint
Elbow - AP Evaluation Criteria
- radial head, neck and tuberosity slightly superimposed with proximal ulna
- open humeroradial joint
- no rotation
Elbow - Lateral Projection
3 joints on same plane
elbow flexed 90, thumb up, superimpose epicondyles - may need sponge under wrist
CR - perpendicular to IR
CP - elbow
collimate 8cm or 3in on either side of the joint
Elbow - Lateral Evaluation Criteria
true lateral position
- superimposed humeral epicondyles
- radial tuberosity facing anteriorly
- tip of coronoid process should cover 2/3 of radial head
- olecranon process in profile
If the coronoid process is too high in relation to the radial head, then…..
humerus is too elevated
- shoulder too high
- elbow too low
If coronoid process is between radial head and condyles, then…..
hand is too low
If radial head is between coronoid process and condyles, then…..
hand is too high
When is the posterior elbow fat pad visible in a lateral projection?
usually only if there is an injury or the elbow is too extended, injury can also cause raised anterior fat pad
Elbow - Medial AP Oblique Projection
Arm extended, hand pronated, epicondyles at 45 angle
CR - perpendicular to IR
CP - middle of elbow
collimate to 8cm or 3” on either side of joint
Elbow - Medial AP Oblique Evaluation Criteria
- coronoid process in profile
- trochlea
- elongated medial epicondyle
- ulna superimposed by the radial head and neck
- olecranon within the olecranon fossa
Elbow - Lateral AP Oblique Projection
Arm extended, hand supinated, rotate externally until epicondyles at 45 angle
CR - perpendicular
CP - middle of elbow
collimate to 8cm or 3” on either side of joint
Elbow - Lateral AP Oblique Evaluation Criteria
- radial head, neck and tuberosity free of ulna
- elongated lateral epicondyle
- capitulum
What do you do if the patient is unable to full extend their arm?
no issues with the lateral projection
Requires 2 different AP projections
- humerus parallel o IR
- forearm paralle to IR
Elbow - Partial Flexion Distal Humerus and Proximal Forearm Projection
supinate hand if possible
CR - perpendicular to IR
CP - middle of elbow
Distal humerus: seat patient so entire humerus is on same plane
Proximal forearm: patient may need to stand to get forearm parallel to IR
Elbow - Partial Flexion Distal Humerus and Proximal Forearm Evaluation Criteria
- area of interest should be free of distortion (area parallel to IR)
- are not of interest will be foreshortened
What is acute flexion?
when patient presents elbow fully flexed and unable to straighten it at all
- can do lateral
2 projections to make AP
- Distal humerus parallel to IR
- proximal forearm - distal humerus still parallel to IR - CR at proximal angle
Elbow - Acute Flexion Distal Humerus Projection
humerus parallel to IR
CR - perpendicular to IR
CP - 5cm or 2” superior to olecranon
Elbow - Acute Flexion Distal Humerus Evaluation Criteria
- no rotation
- humerus and forearm superimposed
- olecranon process and distal humerus without distortion
Elbow - Acute Flexion Proximal Forearm Projection
humerus parallel to IR
CR - perpendicular to forearm
CP - 5cm or 2” superior to olecranon
REMEMBER SID
Elbow - Acute Flexion Proximal Forearm Evaluation Criteria
- no rotation
- proximal radius and ulna with minimal distortion
- joint space is more open than on distal humerus image
Elbow - Radial Head Series Projection
4 views
- shows the entire circumference of the radial head free of superimposition
- positioning set up same as for the lateral elbow
1. hand supinated as much as possible
2. hand in lateral position
3. hand pronated
4. hand internally rotated
Elbow - Radial Head Series Evaluation Criteria
- radial head partially superimposed by coronoid, but seen in all 4 images
- elbow flexed 90
- radial tuberosity anterior for first 2, posterior for latter 2
What is the Coyle Method?
Axiolateral elbow
Same position as lateral elbow but hand pronated
CR - 45 towards shoulder
CP - mid elbow
collimate 8cm or 3” on either side of joint
What are the advantages of the Coyle Method?
- radial head, neck and tuberosity mostly free of superimposition
- open joint between radius and capitulum
- elongated epicondyles
