Clavicle AP Axial is a radiography positioning projection of the Upper Extremity. Erect or supine, CR 15-30 degrees cephalad. Most of the clavicle above the ribs. SID 40". The centering point is located midshaft of the clavicle, with CR angled cephalad to clear the clavicle from ribs. The central ray is angled 15-30 degrees cephalad to project most of the clavicle above the scapula and ribs (thin patients 25-30 degrees, broad-chested patients 15-20). Image-quality criteria include entire clavicle from sternal end to acromion visualized, most of the clavicle projected above the scapula and the 2nd and 3rd ribs. The SID is 40 inches (102 cm).
Anatomy demonstrated
- Clavicle projected above the ribs, with its medial end over the thorax.
- Sternal end of clavicle.
- Midshaft of clavicle.
- Acromial end of clavicle.
- Sternoclavicular joint.
- Acromioclavicular joint.
Patient preparation
- WARNING: suspected fracture or destructive disease: Merrill's uses the supine position to reduce the possibility of fragment displacement or additional injury.
- Verify patient identity using two identifiers.
- Remove necklaces and other radiopaque objects from the region to be radiographed.
- Position patient erect or supine, with the posterior shoulder against the IR or tabletop and no rotation.
- Keep arms at sides in a relaxed position.
- Straighten spine and keep shoulders level.
Position & centering point
Midshaft of the clavicle, with CR angled cephalad to clear the clavicle from ribs.
Central ray
Angled 15-30 degrees cephalad to project most of the clavicle above the scapula and ribs (thin patients 25-30 degrees, broad-chested patients 15-20).
Exposure / technique
- kVp
- N/A
- mAs
- N/A
- SID
- 40" (102 cm)
- Notes
- Erect or supine. CR angled 15-30 degrees cephalad (Merrill's standing lordotic option: 0-15 degrees). Breathing: suspended at the end of inspiration, which helps raise the clavicles. Suspected fracture or destructive disease: Merrill's AP section uses the supine position to reduce the possibility of fragment displacement or additional injury. Bontrager allows erect or supine. Bontrager digital range: 75 to 85 kV. Merrill's chart has no row for the AP axial, so no mAs is given.
Image-quality criteria
- Entire clavicle from sternal end to acromion visualized.
- Most of the clavicle projected above the scapula and the 2nd and 3rd ribs.
- Only the medial clavicle superimposed by the 1st and 2nd ribs.
- Medial and lateral clavicle sharp and well-defined.
- Sternal and acromial ends visible, with the clavicle more horizontal than on the AP.
- Collimation: to the clavicle, including both AC and SC joints (Bontrager); include 1.5 inches above the shoulder and 1 inch beyond its lateral aspect (Merrill's).
Common errors
- 1 Insufficient cephalad angle leaves clavicle superimposed on ribs.
- 2 CR angle not matched to the patient: thin patients need 25-30 degrees, broad-chested patients 15-20.
- 3 Shoulders not in the same horizontal plane.
- 4 CR not directed to the midshaft of the clavicle.
Clinical indications
- Fractures or dislocations of the clavicle.
- Departmental routines commonly include both the AP and AP axial.