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Chest:

PA:

Evaluating for Rotation:

Evaluate distances between vertebral column and the sternal ends of the clavicles

No Rotation: equidistant

Rotation: sternal end of the clavicle that is the farthest away from the midline of the vertebral column represents the side farthest away from the IR.

Compare the lengths of the posterior ribs:

No Rotation: lengths are equal on both sides

Rotation: side with the greatest posterior rib length indicates the side farthest from the IR.

Distinguishing Scoliosis from Rotation:

Compare the distance from the vertebral column to the lateral lung edges down the length of the lungs.

Rotated: distances are uniform down the length of the lung field, although when both lungs are compared, the distance is shorter on one side.

Scoliosis: the vertebral column to lateral lung edge distances vary down the length of each lung and between each lung. The amount of distance variation increases with the severity of the scoliosis.

Clavicle Positioning:

Correct: accurate clavicle positioning lowers the lateral clavicles, positioning the middle and lateral clavicles away from the apical chest region and providing better visualisating of the apical lung field.

Incorrect: when imaged without depression of the shoulders, the lateral ends of the clavicles are elevated, causing the middle and lateral clavicles to be demonstrated within the apical chest region.

Scapulae Positioning:

Correct: scapulae outside the lung field due to sufficiently rolling the shoulders and elbows anteriorly.

Incorrect: scapulae seen superimposing the superolateral lung field which may prevent detection of abnormalities in the periphery of the lungs.

Midcoronal Plane Tilting: the tilt of the superior midcoronal plane with the IR determines the relationship of the manubrium to the thoracic vertebral level, the amount of apical lung field seen above the clavicles and the degree of lung and heart foreshortening.

No Midcoronal Tilt: the manubrium is positioned at the level of the 4th thoracic vertebra and about 2.5cm of the apices are visible above the clavicles. The lungs and heart are shown without foreshortening.

Anterior Midcoronal Tilt (Kyphotic): lungs and heart are foreshortened, the manubrium is at the level of the 5th thoracic vertebra or lower, and more than 2.5cm of the apices are seen above the clavicles. Often common with patients with large breasts or abdomens.

Posterior Midcoronal Tilt (Lordosis): lungs and heart are foreashortened, manubrium is situated at a level between the first and third thoracic vertebrae and less than 2.5cm of lung is seen above the clavicles.

Inspiration: want to see 8-10 posterior ribs above the diaphragm.

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Lateral:

Evaluating for Rotation:

Evaluate the posterior ribs. The ribs farthest away from the IR will be magnified and seem more posterior than the ribs closest to the IR due to increased OID.

Rotation: if there is more than 1.25cm of space between the posterior ribs.

Also, distinguish left and right lungs by looking at the hemidiaphragms. The L hemidiaphragm will be the closest to the fundus of the stomach and therefore a gastric bubble if present.

If there is lung tissue anterior to the sternum in a L lateral, then the R lung is rotated anteriorly. Lung tissue does not appear anteriorly if the L side is rotated anteriorly.

MSP Positioning and Hemidiaphragm Visualisation: ensure patients MSP is parallel to IR.

Correct: R diaphragm naturally higher in most patients due to placement of liver however they usually appear at the same level due to magnification of the R side in a L lateral.

Incorrect: for a L lateral, if MSP curves in to IR, R diaphragm will appear lower than left, even though it naturally sits higher.

AP Mobile:

Evaluating for Rotation: Due to poor IR balance or poor side to side CR alignment. To prevent, align the IR and the midcoronal plane parallel with the bed. Angle CR until perpendicular with IR. Evaluate distances between the vertebral column and the sternal ends of the clavicles.

No Rotation: equidistant

Rotation: sternal end of the clavicle that is the farthest away from the midline of the vertebral column represents the side closest to the IR.

Also compare the lengths of the posterior ribs as for the PA Erect Chest.

Cephalic-Caudal CR alignment: determines relationship of manubrium to the thoracic vertebra, the amount of apical lung field seen above the clavicles and the contour of the posterior ribs. Position CR perpendicular to sternum. The more angulation is malpositioned, the more distorted the antomy.

Caudal Angle: moves the manubrium inferior to T4, demonstrates more than 2.5cm of apices above the clavicles and changes the posterior rib contour to vertical. Elongates the heart and lung structures.

Cephalic Angle: projects the manubrium superior to T4, demonstrating less than 2.5cm of apices above the clavicles and changes the posterior rib contour to horizontal. Foreshortens the heart and lung structures.

Follow the rest of the PA Chest requirements involving clavicles, scapulae and inspiration (if the patients condition allows).

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Abdomen:

Supine:

Evaluating for Rotation:

Evaluate the distance from the pedicles to the spinous processes on each side, compare the widths of the iliac wings and evaluating the centering of the sacrum within the inlet pelvis.

No Rotation: equidistant

Rotation: the distance from the pedicles to the spinous processes is greater on the side of the vertebrae than on the other, one iliac wing is narrower than the other, or if sacrum is rotated toward on side of the inlet. The side with the smaller distance, the narrower iliac wing and the side toward which the sacrum is rotated is the side of the patient positioned farther from the IR.

Elbow:

AP:

Evaluating for Rotation:

Humeral Epicondyles and Radial Head and Ulna Relationship:

No Rotation: epicondyles are seen in profile and about 0.6cm / 1/8th of the head of radius is seen superimposing the ulna

Rotation: Epicondyles are not visualized in profile, and more or less than one eighth [0.6 cm] of the radial head superimposes the ulna. If the epicondyles are not demonstrated in profile, evaluate the degree of radial head superimposition of the ulna to determine how to reposition for an AP projection.

Over-rotation: If less than one eighth of the radial head is superimposed over the ulna, the elbow has been laterally (externally) rotated.

Insufficient Rotation: If more than one eighth of radial head is superimposed over the ulna, the elbow has been medially (internally) rotated.

Radial Tuberosity:

No Rotation / Accurate AP Positioning: the radial tuberosity is demonstrated in profile medially and the radius and ulna are aligned parallel with each other as long as the wrist is in an AP projection.

Rotation: If the wrist cannot be brought into an AP projection, the AP elbow projection will demonstrate varying radial and ulnar relationships and radial tuberosity visualizations. When the wrist has been internally rotated to a PA projection, the radius crosses over the ulna and the radial tuberosity is rotated posteriorly, out of profile.

Evaluating for Elbow Flexion: Flexion of the elbow joint distorts the elbow structures and draws the olecranon from the olecranon process on an AP projection. How a flexed elbow is positioned with respect to the IR determines which elbow structures are distorted.

The elbow joint space will be demonstrated as an open space only when the forearm is positioned parallel with the IR

Humerus Parallel to IR and forearm elevated: demonstrates an undistorted distal humerus, whereas the proximal forearm is distorted, visualizing a closed elbow joint space and the radial head articulating surface imaged partially on end.

Forearm Parallel to IR and humerus elevated: demonstrates an undistorted proximal forearm and an open elbow joint space, and a foreshortened distal humerus.

Flexed elbow balanced on apex of elbow (both humerus and forearm elevated): both the humerus and the forearm are foreshortened as described. The severity of the distortion increases with increased elbow flexion

External Oblique:

Accurate positioning for an AP lateral oblique elbow projection rotates the radius away from the ulna, demonstrating the ulna without radial superimposition and is accomplished when the humeral epicondyles are placed at a 45-degree oblique with the IR.

Evaluating degree of Obliquity:

Inadequate Obliquity: the radial head and/ or the radial tuberosity still partially superimpose the ulna

Over Obliqued: the coronoid process partially superimposes the radial head, the radial tuberosity and ulna demonstrate no superimposition, and the radial tuberosity is no longer in profile.

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Lateral:

Importance of Elbow Flexion:

Flexion of 90 degrees: When the elbow is flexed 90 degrees, the forearm can be elevated to align the anatomic structures of the distal humerus properly, and displacement of the anterior and posterior fat pads can be used as signs to determine diagnosis.

Incorrect Flexion: fat pads can be displaced by poor positioning instead of joint pathology, interfering with their diagnostic usefulness When the arm is extended, nonpathologic displacement of the anterior fat pad results from intraarticular pressure placed on the joint. Nonpathologic displacement of the posterior fat pad is a result of positioning of the olecranon within the olecranon fossa, which causes proximal and posterior displacement of the pad.

Evaluating True Lateral Position:

Humeral Epicondyles:

Proximal humerus and distal forearm are positioned so the humeral epicondyles are situated directly on top of each other, placing an imaginary line drawn between them perpendicular to the IR.

Correct Humeral Epicondyle Positioning: aligns the trochlear sulcus, capitulum, and medial trochlea into three concentric (having the same center) arcs.

Trochlear sulcus: is the small center arc. It moves very little when a positional change is made and works like a pivoting point between the capitulum and medial aspect of the trochlea.

Medial aspect of the Trochlea: The largest arc. It is demonstrated very close to and slightly superimposed on the curve of the trochlear notch of the ulna.

Capitulum: intermediate-sized arc.

When these three arcs are accurately aligned, the elbow joint is visualised as an open space and the anterior and proximal surfaces of the radial head and coronoid process are aligned.

Proximal Humerus Positioning (depression and elevation):

Determines the alignment of the distal surfaces of the capitul and medial trochlea, and the anterior alignment of the radial head and coranoid process.

Shoulder too High: distal capitulum surface is demonstrated too far distal to the distal surface of the medial trochlea and the radial head is placed too far posteriorly to the coronoid process.

Shoulder too Low: distal capitulum surface is demonstrated too far proximal to the distal medial trochlea surface and the radial head is positioned too far anteriorly to the coronoid process.

Distal Forearm positioning (depression and elevation):

Determines the anterior alignment of the capitulum and medial trochlea and the proximal alignment of the radial head and coronoid process.

Wrist too Low: shows the capitulum too far anteriorly to the medial trochlea and the radial head distally to the coronoid process

Wrist too High: shows the capitulum too far posteriorly to the medial trochlea and the radial head proximally to the coronoid process

Radial Tuberosity Positioning:

Visibility of the radial tuberosity on the lateral projection is determined by the position of the wrist.

Lateral Wrist: the radial tuberosity is not demonstrated on the projection as it is situated on the medial aspect of the radius and is superimposed by the radius.

Wrist Externally Rotated: the radial tuberosity is rotated to the anterior arm surface and is demonstrated in profile anteriorly.

Wrist Internally Rotated: rotates the radial tuberosity to the posterior arm surface and demonstrates it posteriorly

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Shoulder:

Lateral Scapula:

Evaluating Rotation:

Using the borders of the scapulae: Thick lateral border, thin medial/vertebral border.

Under Rotated: vertebral border superimposes the thorax or is demonstrated closer to the thorax than the lateral border.

Perfect: lateral and vertebral borders of the scapulae are superimposed.

Over Rotated: lateral border is superimposed by the thorax or positioned closer to the thorax than the vertebral border.

Evaluating Scapula:

Midcoronal Tilt: causing foreshortening of the scapulae.

Good Positioning: upper thoracic spine is straightened and the midcoronal plane is vertical = scapulae body demonstrated without longitudinal foreshortening. The superior scapular angle and clavicle are shown on the same transverse plane.

Patient tilted towards IR (Kyphosis): the clavicle is demonstrated inferior to the superior scapular angle. Can account for a kyphosis by angling the CR perpendicular to the Scapular.

Patient tilted away from IR: the clavicle is seen superior to the superior scapular angle

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Knee:

AP:

Evaluating for Rotation:

Tibia Fibular Relationship:

No Rotation:

Rotation:

Too Internally Rotated: Tibia will superimpose less than half the fibular head. Intercondylar eminences will not appear equal.

Too Externally Rotated: Tibia will superimpose more than half the fibular head. Intercondylar eminences will not appear equal.

Effect of Knee Flexion:

Full Extension: shows patella and intercondylar fossa as required.

Knee Flexion: patella shifts distally and medially onto the patellar surface of the femur and then laterally into the intercondylar fossa (A C-shaped path open laterally). Therefore the patella is demonstrated at different positions depending on the degree of knee flexion.

Generally, when the knee is flexed 20 degrees, the patella is demonstrated on the patellar surface.

With 30 to 70 degrees of knee flexion, the patella is demonstrated between the patellar surface and the intercondylar fossa.

At 90 degrees to full knee flexion, the patella is demonstrated within the intercondylar fossa.

Lateral:

Evaluating for Rotation:

Using the Femoral Condyles:

No Rotation: medial and lateral femoral condyles are superimposed.

Rotation: femoral condyles are not superimposed.

How to fix: distinguish the lateral and medial condyles by locating the rounded bony tubercle (adductor tubercle) on the medial condyle. The lateral condyle is smooth posteriorly.

Using the Fibular Head:

If fibular head is superimposed more than 1/2, knee was internally rotated (on a mediolateral)

If fibular head is not superimposed enough, or at all, the knee was externally rotated (on a mediolateral)

Adjusting for poor CR angulation:

If an inaccurate CR angulation is used on a lateral knee, the distal articulating margins of the femoral condyles are not aligned, the joint space is narrowed or closed, and the distance from the tibial plateau to the femoral head is more or less than 0.5 inch (1.25 cm).

Cephalic CR angulation required but not needed: demonstrates the distal margin of the medial condyle distal to the distal margin of the lateral condyle and less that 0.5 inch (1.25 cm) of distance is demonstrated between the fibular head and tibial plateau

Cephalic angle used but not required or angle too great:distal margin of the medial condyle is projected proximal to the distal margin of the lateral condyle and more than 0.5 inch (1.25 cm) of distance is demonstrated between the fibular head and the tibial plateau