DR Topic 3: Elbow & Forearm imaging Flashcards
(47 cards)
Exposure factors and rationale
55kVp
- High contrast image (large attenuation diff between adjacent anatomical structures
- Low beam penetration as small/thin anatomical area
100mA
- Require fine focus for image detail
- Minimal chance of movement artefact thus exposure time no issue
0.04s
- Provides required mAs of 4
Grid
- No, small anatomical area, minimal scatter radiation
Elbow & forearm projections
- AP forearm
- Lateral forearm
- PA forearm (trauma)
- HB PA elbow (as elbow is lateral in trauma PA forearm)
- HB lateral forearm (trauma)
- AP elbow
- Lateral elbow
- AP external oblique elbow
- Lateral head of radius
- Axial elbow
AP forearm imaging technique
- Arm extended, hand lies in supination
- Centre midway between wrist and elbow joints
- Collimate elbow, wrist, shafts of radius and ulna, soft tissue
Lateral forearm imaging technique
- Arm flexed at elbow, medial aspect in contact with IR, shoulder, elbow, wrist lying in same plane
- Centre midway between wrist and elbow joints, on medial aspect of forearm
- Collimate elbow, wrist, shafts of radius and ulna, soft tissue
PA forearm (trauma) imaging technique
- Palmar aspect of forearm from wrist to elbow in contact with IR with 90 degree elbow flexion
- Centre midway between wrist and elbow joints
- Collimate elbow, wrist, shafts of radius and ulna, soft tissue
HB PA elbow (trauma) imaging technique
- Forearm on pad in trauma position, IR held by patient
- Centre midway between humeral epicondyles
- Collimate distal third of humerus, proximal third of radius and ulna, soft tissue
HB lateral forearm (trauma) imaging technique
- Medial border of extended elbow in contact with IR, IR is medial to forearm
- Centre mid forearm region
- Collimate wrist, elbow, radius and ulna shafts, soft tissue
AP elbow imaging technique
- Arm extended at elbow, posterior aspect of elbow in contact with IR, wrist, elbow, shoulder in same plane
- Centre midway between humeral epicondyles
- Collimate proximal radius ulna, elbow joint, distal shaft of humerus, soft tissue
Lateral elbow imaging technique
- Flex arm 90 degrees at elbow, wrist externally rotated, medial aspect of elbow in contact with IR, shoulder elbow wrist joints in same plane
- Centre over lateral humeral epicondyle
- Collimate prox radius ulna, elbow joint, distal shaft of humerus, soft tissue
AP external oblique elbow imaging technique
Only do if patient can extend elbow
- From AP, externally rotate arm 20 degrees, pad to aid immobilisation
- Centre over middle of crease of elbow
- Collimate prox radius ulna, elbow joint, distal shaft of humerus, soft tissue
Lateral head of radius imaging technique
Only do if patient can extend elbow
- From lateral elbow, rotate forearm internally until hand in pronation and in contact with tabletop
- Over lateral humeral epicondyle
- Collimate prox radius ulna, elbow joint, distal shaft of humerus, soft tissue
Axial elbow imaging technique
- Elbow flexed, posterior aspect of humerus in contact with IR
- Centre between condyles of humerus
- Collimate prox radius ulna, elbow joint, distal shaft of humerus, soft tissue
Elbow & Forearm pathologies
- Midshaft radius and ulna fracture
- Greenstick fracture
- Monteggia fracture/dislocation
- Galeazzi fracture/dislocation
- Proximal ulna fracture
- Radial head fracture
- Olecranon fracture
- Supracondylar fracture
- Elbow dislocation
- Bone tumours
Midshaft radius and ulna fracture
Fractures in the middle portion in both the radius and ulna
Projections and rationale for midshaft radius and ulna fracture
PA forearm (trauma)
- Assess malalignment of radius and ulna, fracture lines
HB PA elbow (trauma)
- Visualise elbow in PA view as elbow is lateral in PA forearm
HB lateral elbow (trauma)
- Assess posterior and anterior displacement of radius and ulna
Radiographic appearance of midshaft radius and ulna fracture
Fracture lines in mid region of radius and ulna, displacement, potential fragmentation
Greenstick fracture
Fracture on one side of the bone, causing a bend on the other side of the bone
Projections and rationale for greenstick fracture
PA forearm (trauma)
- Assess malalignment of radius and ulna, fracture lines
HB PA elbow (trauma)
- Visualise elbow in PA view as elbow is lateral in PA forearm
HB lateral elbow (trauma)
- Assess posterior and anterior displacement of radius and ulna
Radiographic appearance of greenstick fracture
Clear fracture on one cortex, angulation of bone shaft and compression of bone
Monteggia fracture/dislocation
Fracture of the ulna (usually proximal third) with dislocation of radial head
Projections and rationale for Monteggia fracture/dislocation
PA forearm (trauma)
- Assess malalignment of radius and ulna, fracture lines
HB PA elbow (trauma)
- Visualise elbow in PA view as elbow is lateral in PA forearm
HB lateral elbow (trauma)
- Assess posterior and anterior displacement of radius and ulna, dislocation of joints
Radiographic appearance of Monteggia fracture/dislocation
Fracture in ulna, dislocation of radial head
Galeazzi fracture/dislocation
Fracture in distal third of radius with dislocation of the distal radioulnar joint (DRUJ)
Projections and rationale for Galeazzi fracture/dislocation
PA forearm (trauma)
- Assess malalignment of radius and ulna, fracture lines
HB PA elbow (trauma)
- Visualise elbow in PA view as elbow is lateral in PA forearm
HB lateral elbow (trauma)
- Assess posterior and anterior displacement of radius and ulna, dislocation of joints
