FISK MODIFICATION
Pathology Demonstrated:
- Pathologies of the intertubercular groove, such as bony projections of the humeral tubercles, are demonstrated.
Technical Factors:
- IR size - 18 x 24 cm (8 x 10 inches), crosswise
- Detail screen cassette, non grid
- 60 +- 5 kV range
- mAs
Erect : 4
Supine: 3
Shielding:
- Place lead shields over pelvic area.
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| Erect superoinferior tangential projection: Fisk Modification |
Patient Position and Central Ray:
Erect (Fisk modification)
- Patient standing, leaning over end of the table with elbow flexed and posterior surface of forearm resting on table, hand supinated holding cassette, head turned away from affected side (lead shield placed between back of IR and forearm reduces backscatter to IR)
- Patient learning forward slightly to place humerus 10 to 15 degrees from vertical.
- CR perpendicular to IR, directed to groove area at mid-anterior margin of humeral head (groove can be located by careful palpation)
Supine:
 |
| Supine inferosuperior tangential projection |
- Patient supine, arm at side, hand supinated
- Veritcal cassette placed on table against top of shoulder and against neck (head turned away from affected side)
- CR 10 to 15 degrees posterior from horizontal, directed to groove at mid-anterior margin of humeral head
- Minimum SID of 40 inches (100 cm)
Collimation:
- Collimate closely on four sides to area of anterior humeral head.
Respiration:
- Suspend respiration during exposure.
Radiographic Criteria:
 |
| Fisk Modification: Erect tangential |
Structure Shown:
- The anterior margin of the humeral head is seen in profile.
- The humeral tubercles and the intertubercular groove are seen in profile.
Position:
- A correct CR angle of 10 to 15 degrees to the long axis of the humeral will demonstrate the intertubercular groove and the tubercles in profile without superimposition of the acromion process.
Collimation and CR:
 |
| Supine Tangential View |
- Collimation should be visible on four sides to area of affected shoulder.
- CR and center of the collimation field should be at the intertubercular groove.
Exposure Criteria:
- Optimal density and contrast with no motion will visualize sharp borders and sharp bony trabecular markings and will demonstrate the complete intertubercular groove seen through soft tissue without excessive density or burnout.
