SUPEROINFERIOR - TRANSAXILLARY ( PA VIEW ) : SHOULDER

MODIFICATION OF HOBBS METHOD
SUPEROINFERIOR PA TRANSAXILLARY PROJECTION


Warning:

• Do not attempt to rotate, force extention, or abduct arm if fracture or dislocation is suspected.

Pathology Demonstrate:

• Fracture and/ or dislocation of the proximal humerus are shown. Bursitis, shoulder impringement, osteoporosis, osteoarthritis, and tensonitis may be demonstrated.

Technical Factor:

• IR size - 18 x 24 cm (8 x 10 inches) lengthwise
• Bucky or stationary grid (CR to centerline of grid)
• 70 +- 5 kV range
• mAs 7

Shielding:

• Place lead shield over pelvis and radiosensitive regions.

Patient Position:

• Tale radiograph with the patient in an erect position or by leaning the patient over the end of the x-ray table. The patient is positioned in a slight 5 to 10 degree anterior oblique.

Part Position:

• The arm is raised superiorly as much as the patient can tolerate.
• The head is turned away from the affected arm.

Central Ray for Hobbs Modification:

• CR is directed perpendicular to the axilla and teh humeral head to pass through the glenohumeral joint.
• Minimum SID is 40 inches (100cm)

Collimation:

• Collimate closely on four sides.

Respiration:

• Suspend respiration during exposure.

RADIOGRAPHIC CRITERIA OF HOBBS MODIFICATION:

Structure Shown:

• Lateral view of proximal humerus in relationship to the glenohumeral articulation is visualized.
• Coracoid process of scapula is seen on end.

Position:

• Arm is seen to be raised superiorly above the body.

Collimation and CR:

• Collimation should be visible on four sides to the affected shoulder.
• CR and center of collimation field should be at the axilla and humeral head.

Superoinferior PA Transaxillary Projection Exposure Criteria:

• Optimal density and contrast with no motion will demonstrate clear, sharp bony trabecular markings.
• The body margins of the acromion and coracoid process will be visible through the humeral head.