RadReview3

Which of the following can be used to demonstrate the intercondyloid fossa? Prone, knee flexed 40 degrees, CR directed caudad 40 degrees to the popliteal fossa. Supine, IR under flexed knee, CR directed cephalad to knee, perpendicular to tibia.

Statement number 1 describes the PA axial projection (*Camp-Coventry method*) for demonstration of the *intercondyloid fossa*. Statement number 2 describes the AP axial projection (*Béclère method*) for demonstration of the *intercondyloid fossa*. The positions are actually the reverse of each other.

What projection was used to obtain the image seen in Figure 2-41? AP, external rotation

An *AP, external rotation, projection of the shoulder* is pictured. The hand is supinated, and the arm is in the anatomical position. Therefore, the greater tubercle (number 3) is well visualized. The greater portion of the clavicle is seen, the acromioclavicular joint (number 1), the acromion process (number 2), the coracoid process (number 4), and the glenohumeral joint (number 5). The coronoid process is located on the ulna.

Which of the following projections will best demonstrate acromioclavicular separation? AP erect, both shoulders

*Acromioclavicular (AC) joints* usually are examined when separation or dislocation is suspected. They must be examined in the erect position because in the recumbent position a separation appears to reduce itself. Both AC joints are examined simultaneously for comparison because separations may be minimal.

Impingement on the wrist's median nerve causing pain and disability of the affected hand and wrist is known as: Carpal tunnel syndrome

*Carpal tunnel syndrome* involves pain and numbness to some parts of the median nerve distribution (i.e., palmar surface of the thumb, index finger, and radial half of the fourth finger and palm). Carpal tunnel syndrome occurs frequently in those who continually use vibrating tools or machinery. *Carpopedal spasm* is spasm of the hands and feet, commonly encountered during hyperventilation. *Carpal boss* is a bony growth on the dorsal surface of the third metacarpophalangeal joint.

What is the most superior structure of the scapula? Acromion process

It is easy to determine the highest point of the scapula when it is viewed laterally. The coracoid process projects anteriorly and is quite superior. However, the acromion process, which is an anterior extension of the scapular spine, projects considerably more superior than the coracoid.

The primary center of ossification in long bones is the: Diaphysis.

Long bones are composed of a shaft, or *diaphysis*, and two extremities. The diaphysis is referred to as the primary ossification center. In the growing bone, the cartilaginous epiphyseal plate (located at the extremities of long bones) is gradually replaced by bone. For this reason, the *epiphyses* are referred to as the secondary ossification centers. The ossified growth area of long bones is the *metaphysis*. *Apophysis* refers to vertebral joints formed by articulation of superjacent articular facets.

Which of the following projections of the elbow should demonstrate the coronoid process free of superimposition and the olecranon process within the olecranon fossa? Medial oblique

On the *AP projection of the elbow*, the radial head and ulna are normally somewhat superimposed. The *lateral oblique* demonstrates the radial head free of ulnar superimposition. The *lateral projection* demonstrates the olecranon process in profile. The *medial oblique* demonstrates considerable overlap of the proximal radius and ulna, but should clearly demonstrate the coronoid process free of superimposition and the olecranon process within the olecranon fossa.

Silver reclamation may be accomplished in which of the following ways? Metallic replacement cartridge Electrolytic plating unit Removal from used film

Unexposed, undeveloped silver is removed from film emulsion in the fixer solution. It is recovered (reclaimed) from the solution and sold. The silver may be reclaimed electrolytically or with a metallic replacement cartridge. Silver may also be reclaimed from processed radiographs or unexposed film.

Which of the following are components of a trimalleolar fracture? Fractured lateral malleolus Fractured medial malleolus Fractured posterior tibia

A *trimalleolar fracture* involves three separate fractures. The lateral malleolus is fractured in the "typical" fashion, but the medial malleolus is fractured on both its medial and posterior aspects. The trimalleolar fracture frequently is associated with subluxation of the articular surfaces.

Adult orthoroentgenography, or radiographic measurement of long bones of an upper or lower extremity, requires which of the following accessories? Bell-Thompson scale Bucky tray

Adult *orthoroentgenography* is the radiographic measurement of long-bone length. It can be required on adults or children having extremity length (especially leg) discrepancies. This can be performed most easily with the use of the metallic Bell-Thompson scale secured to the x-ray tabletop adjacent to the limb being examined (or between both limbs for simultaneous bilateral examination). A 14 × 17 inch cassette is in the Bucky tray (to permit movement of the cassette between exposures), and three well-collimated exposures are made—at the hip joint, the knee joint, and the ankle joint.

Which of the following pathologic conditions are considered additive conditions with respect to selection of exposure factors? Osteoma Bronchiectasis Pneumonia

All these conditions are considered technically additive because they all involve an increase in tissue density. *Osteoma, or exostosis*, is a (usually benign) bony tumor that can develop on bone. *Bronchiectasis* is a chronic dilatation of the bronchi with accumulation of fluid. *Pneumonia* is inflammation of the lung(s) with accumulation of fluid. Additional bony tissues and the pathologic presence of fluid are additive pathologic conditions and require an increase in exposure factors. Destructive conditions such as osteoporosis require a decrease in exposure factors.

Which of the following is (are) true regarding radiographic examination of the acromioclavicular joints? The procedure is performed in the erect position. Use of weights can improve demonstration of the joints.

Evaluation of the *acromioclavicular joints requires bilateral AP or PA erect projections with and without the use of weights*. Weights are used to emphasize the minute changes within a joint caused by separation or dislocation. Weights should be anchored from the patient's wrists rather than held in the patient's hands because this encourages tightening of the shoulder muscles and obliteration of any small separation.

In the lateral projection of the ankle, the: Talotibial joint is visualized. Tibia and fibula are superimposed.

In a *lateral projection of the ankle*, the tibia and fibula are superimposed, and the foot is somewhat dorsiflexed to better demonstrate the talotibial joint. The talofibular joint is not visualized because of superimposition with other bony structures. It may be well visualized in the medial oblique projection of the ankle.

Which of the following positions will separate the radial head, neck, and tuberosity from superimposition on the ulna? Lateral oblique

In the *AP projection of the elbow*, the proximal radius and ulna are partially superimposed. In the *lateral projection*, the radial head is partially superimposed on the coronoid process, facing anteriorly. In the *medial oblique* projection, there is even greater superimposition. The *lateral oblique* projection completely separates the proximal radius and ulna, projecting the radial head, neck, and tuberosity free of superimposition with the proximal ulna.

To better visualize the knee-joint space in the radiograph in Figure 2-31, the radiographer should: Angle the CR 5 to 7 degrees cephalad.

In the *lateral projection of the knee*, the joint space is obscured by the magnified medial femoral condyle unless the CR is angled 5 to 7 degrees cephalad. The degree of flexion of the knee is important when evaluating the knee for possible transverse patellar fracture. In such a case, the knee should not be flexed more than 10 degrees. The knee normally should be flexed 20 to 30 degrees in the lateral position.

Which of the following positions would best demonstrate the proximal tibiofibular articulation? 45-degree internal rotation

In the AP projection, the proximal fibula is at least partially superimposed on the lateral tibial condyle. Medial rotation of 45 degrees will "open" the *proximal tibiofibular articulation*. Lateral rotation will obscure the articulation even more.

Which of the following projections of the elbow should demonstrate the radial head free of ulnar superimposition? Lateral oblique

On the *AP projection of the elbow*, the radial head and ulna normally are somewhat superimposed. The *lateral oblique projection* demonstrates the radial head free of ulnar superimposition. The *lateral projection* demonstrates the olecranon process in profile. The *medial oblique projection* demonstrates considerable overlap of the proximal radius and ulna but should clearly demonstrate the coronoid process free of superimposition and the olecranon process within the olecranon fossa.

The AP oblique projection (medial rotation) of the elbow demonstrates which of the following? Olecranon process within the olecranon fossa. Coronoid process free of superimposition.

The *AP oblique projection (medial rotation) of the elbow* superimposes the radial head and neck on the proximal ulna. It demonstrates the olecranon process within the olecranon fossa, and it projects the coronoid process free of superimposition. The radial head is projected free of superimposition in the *AP oblique projection (lateral rotation)* of the elbow.

Which of the following positions would be the best choice for a right shoulder examination to rule out fracture? AP and scapular Y

The *AP shoulder projection* will give a general survey and show mediolateral and inferosuperior joint relationships. The *scapular Y* position (LAO or RAO) is employed to demonstrate anterior (subcoracoid) or posterior (subacromial) humeral dislocation. The humerus normally is superimposed on the scapula in this position; any deviation from this may indicate dislocation. Rotational views must be avoided in cases of suspected fracture. The AP and scapular Y combination is the closest to two views at right angles to each other.

Which of the following articulations participate(s) in formation of the ankle mortise? Talotibial Talofibular

The *ankle mortise*, or ankle joint, is formed by the articulation of the tibia, fibula, and talus. Two articulations form the ankle mortise: the talotibial and talofibular articulations. The calcaneus is not associated with formation of the ankle mortise.

Ulnar deviation will best demonstrate which carpal(s)? Lateral carpals Scaphoid

The *carpal scaphoid* is somewhat curved and consequently foreshortened radiographically in the PA position. To better separate it from the adjacent carpals, the *ulnar deviation* maneuver is employed frequently. In addition to correcting foreshortening of the scaphoid, ulnar deviation opens the interspaces between adjacent lateral carpals. Radial deviation is used to better demonstrate medial carpals.

Which position of the shoulder demonstrates the lesser tubercle in profile medially? Internal rotation

The *external rotation* position is the true AP position and places the greater tubercle in profile laterally and places the lesser tubercle anteriorly. The *internal rotation* position demonstrates the lesser tubercle in profile medially and places the humerus in a true lateral position; the greater tubercle is seen superimposed on the humeral head. The epicondyles should be superimposed and perpendicular to the IR. The *neutral position* places the epicondyles about 45 degrees to the IR and places the greater tubercle anteriorly but still lateral to the lesser tubercle.

Which of the following is (are) located on the proximal aspect of the humerus? Intertubercular groove

The *intertubercular (bicipital) groove* is located on the proximal humerus, distal to the head, between the greater and lesser tubercles. The distal humerus articulates with the radius and ulna to form the elbow joint. The lateral aspect of the distal humerus presents a raised, smooth, rounded surface, the *capitulum*, which articulates with the superior surface of the radial head. The *trochlea* is on the medial aspect of the distal humerus and articulates with the *semilunar notch* of the ulna. Just proximal to the capitulum and the trochlea are the lateral and medial epicondyles; the medial is more prominent and palpable. The *coronoid fossa* is found on the anterior distal humerus and functions to accommodate the coronoid process with the elbow in flexion.

Which of the following projections or positions will best demonstrate subacromial or subcoracoid dislocation? PA oblique scapular Y

The *scapular Y* refers to the characteristic Y formed by the humerus, acromion, and coracoid processes. The patient is placed in a PA oblique position—an RAO or LAO position depending on which is the affected side. The midcoronal plane is adjusted approximately 60 degrees to the IR, and the affected arm remains relaxed at the patient's side. The scapular Y position is employed to demonstrate anterior (subcoracoid) or posterior (subacromial) humeral dislocation. The humerus normally is superimposed on the scapula in this position; any deviation from this may indicate dislocation.

Which of the following projections of the ankle would best demonstrate the mortise? Medial oblique 15 to 20 degrees.

The 15-degree medial oblique projection is used to demonstrate the *ankle mortise (joint)*. Although the joint is well demonstrated in the 15-degree medial oblique projection, there is some superimposition of the distal tibia and fibula, and greater obliquity is required to separate the bones. To best demonstrate the *distal tibiofibular articulation*, a 45-degree medial oblique projection of the ankle is required.

In which of the following projections is the talofibular joint best demonstrated? Medial oblique

The AP projection demonstrates superimposition of the distal fibula on the talus; the joint space is not well seen. The *15- to 20-degree medial oblique ankle* position shows the entire mortise joint; the talofibular joint is well visualized, as well as the talotibial joint. There is considerable superimposition of the talus and fibula in the lateral and lateral oblique projections.

All the following can be associated with the elbow joint: The capitulum. The trochlea. The epicondyles.

The distal humerus articulates with the radius and ulna to form the elbow joint. The lateral aspect of the distal humerus presents a raised, smooth, rounded surface, the *capitulum*, that articulates with the superior surface of the radial head. The *trochlea* is on the medial aspect of the distal humerus and articulates with the *semilunar/trochlear notch* of the ulna. Just proximal to the capitulum and trochlea are the lateral and medial epicondyles; the medial is more prominent and palpable. *Lateral epicondylitis ("tennis elbow")* is a painful condition caused by prolonged rotary motion of the forearm. The *tubercles* are prominences located at the proximal humerus and are anatomically remote from the elbow joint.

All the following can be associated with the distal ulna: Head. Radioulnar joint. Styloid process.

The distal ulna presents a head and styloid process and articulates with the distal radius to form the distal radioulnar joint. The ulna is slender distally but enlarges proximally and becomes the larger of the two bones of the forearm. At its proximal end, the ulna presents the *olecranon process* (posteriorly) and *coronoid process* (anteriorly) that are joined by a large articular cavity, the *semilunar, or trochlear notch*. The coronoid process fits into the humeral coronoid fossa during flexion, and the olecranon process fits into the humeral olecranon fossa during extension. Just distal and lateral to the semilunar/trochlear notch is the *radial notch*, which provides articulation for the radial head to form the proximal radioulnar articulation. The ulna is the principal bone of the elbow joint, and the radius is the principal bone of the wrist joint.

Which of the following projections/positions would best demonstrate structure number 6 seen in Figure 7-7? Lateral projection

The figure shows a *posterior view of the elbow*. The distal posterior humerus (number 1) is seen, as well as the proximal posterior radius (number 4) and ulna (number 3). Additional structures identified are the medial epicondyle (number 2), the olecranon fossa (number 5), olecranon process (number 6), lateral epicondyle (number 7), and radial head (number 8) The olecranon process (number 6) can best be demonstrated in the *lateral projection*; it can also be demonstrated in the acute flexion position. The *AP internal oblique* will demonstrate the coronoid process; the *AP external oblique* will demonstrate the radial head free of superimposition.

To evaluate the interphalangeal joints in the oblique and lateral positions, the fingers: Must be supported parallel to the IR.

The fingers must be supported parallel to the IR (e.g., on a finger sponge) in order that the joint spaces parallel the x-ray beam. When the fingers are flexed or resting on the cassette, the relationship between the joint spaces and the IR changes, and the joints appear "closed."

Which of the following articulate(s) with the bases of the metatarsals? The cuboid The cuneiforms

The foot is composed of the 7 tarsal bones, 5 metatarsals, and 14 phalanges. The metatarsals and phalanges are miniature long bones; each has a shaft, base (proximal), and head (distal). The *bases* of the first to third metatarsals articulate with the three cuneiforms. The *bases* of the fourth and fifth metatarsals articulate with the cuboid. The *heads* of the metatarsals articulate with the bases of the first row of phalanges.

In which of the following projections was the image in Figure 2-7 made? Medial oblique

The image illustrates a *medial oblique (internal rotation) projection of the elbow* with epicondyles 45 degrees to the IR. An oblique view of the proximal radius and ulna and the distal humerus is obtained. This projection is particularly useful to demonstrate the coronoid process in profile, the trochlea, and the medial epicondyle. The *external oblique (lateral rotation)* projection demonstrates the radial head free of superimposition as well as the radial neck and the humeral capitulum. The *acute flexion projection (Jones Method)* of the elbow is a two-projection method demonstrating the elbow anatomy when the part cannot be extended for an AP projection.

Which of the following is (are) distal to the tibial plateau? Tibial condyles Tibial tuberosity

The knee joint is formed by the femur, tibia, and patella. The most superior aspect of the tibia is the tibial plateau—formed by the tibial condyles just distal to it. The proximal tibia also presents the tibial tuberosity on its anterior surface, just distal to the condyles. Proximal to the tibial plateau, and articulating with it, are the femoral condyles—the deep notch separating them is the intercondyloid fossa. The term *proximal* refers to a part located closer to the point of attachment; the term *distal* refers to a part located farther away from the point of attachment.

The term varus refers to: Turned inward.

The term *varus* refers to bent or turned inward. In *genu varus*, the tibia or femur turns inward causing bowlegged deformity; in *talipes varus*, the foot turns inward (clubfoot deformity). The term *valgus* refers to a part turned/deformed outward—as in hallux valgus and talipes valgus. *Hallux valgus* is angulation of the great toe away from the midline; *talipes valgus* is a foot deformity with the heel turned outward—a component of clubfoot.

All elbow fat pads are best demonstrated in which position? Lateral

There are three important fat pads associated with the elbow. The anterior fat pad is located just anterior to the distal humerus. The posterior fat pad is located within the olecranon fossa at the distal posterior humerus. The supinator fat pad/stripe is located at the proximal radius just anterior to the head, neck, and tuberosity. The posterior fat pad is not visible radiographically in the normal elbow. All three fat pads can be demonstrated only in the *lateral projection of the elbow*.

Which of the following is (are) valid evaluation criteria for a lateral projection of the forearm? The radius and the ulna should be superimposed distally. The coronoid process and the radial head should be partially superimposed. The humeral epicondyles should be superimposed.

To accurately position a *lateral forearm*, the elbow must form a 90-degree angle with the humeral epicondyles superimposed. The radius and ulna are superimposed distally. Proximally, the coronoid process and radial head are partially superimposed. Failure of the elbow to form a 90-degree angle or the hand to be lateral results in a less than satisfactory lateral projection of the forearm.

In a lateral projection of the normal knee, the: Fibular head should be somewhat superimposed on the proximal tibia. Patellofemoral joint should be visualized. Femoral condyles should be superimposed.

To better visualize the joint space in the *lateral projection of the knee*, 20 to 30 degrees of flexion is recommended. The femoral condyles are superimposed so as to demonstrate the patellofemoral joint and the articulation between the femur and the tibia. The head of the fibula will be slightly superimposed on the proximal tibia. The correct degree of forward or backward body rotation is responsible for visualization of the patellofemoral joint. Cephalad tube angulation of 5 to 7 degrees is responsible for demonstrating the articulation between the femur and the tibia (by removing the magnified medial femoral condyle from superimposition on the joint space).

The scapula shown in Figure 2-29 demonstrates: Its posterior aspect.

Visualization of the scapular spine (number 13) indicates that this is a view of the *posterior aspect of the scapula*. The scapula's anterior, or costal, surface is that which is adjacent to the ribs. The scapula has no sternal articulation.

Which of the following projections require(s) that the humeral epicondyles be perpendicular to the IR? Lateral forearm Internal rotation shoulder

When the *arm is placed in the AP position*, the epicondyles are parallel to the plane of the IR, and the shoulder is placed in external rotation. In this position, an AP projection of the humerus, elbow, and forearm can be obtained; it places the greater tubercle of the humerus in profile. For the *lateral projection of the humerus* and the internal rotation projection of the shoulder, the arm is internally rotated, elbow somewhat flexed, with the back of the hand against the thigh, and the epicondyles are superimposed and perpendicular to the IR. The lateral projections of the humerus, elbow, and forearm all require that the epicondyles be perpendicular to the plane of the cassette.

Which of the following projections require(s) that the shoulder be placed in external rotation? AP humerus

When the *arm is placed in the AP position*, the epicondyles are parallel to the plane of the cassette, and the shoulder is placed in external rotation. In this position, an AP projection of the humerus, elbow, and forearm can be obtained. For the *lateral projection* of the humerus, elbow, or forearm, the epicondyles must be perpendicular to the plane of the cassette.

How can OID be reduced for a PA projection of the wrist? Flex the metacarpophalangeal joints.

When the hand is pronated and the fingers are extended for a *PA projection of the wrist*, the wrist arches, and an OID is introduced between the wrist and the cassette. To reduce this OID, the metacarpophalangeal joints should be flexed slightly. This maneuver will bring the anterior surface of the wrist into contact with the cassette.

Which of the following statements is (are) true regarding the images shown in Figure 2-33? Image B is positioned in internal rotation. The greater tubercle is better demonstrated in image A.

When the shoulder is placed in *internal rotation*, a greater portion of the glenoid fossa is superimposed by the humeral head, and the lesser tubercle is visualized, as in image B. The *external rotation* position (image A) removes the humeral head from a large portion of the glenoid fossa and better demonstrates the greater tubercle.

Which of the following articulations may be described as diarthrotic? Knee Temporomandibular joint (TMJ)

*Diarthrotic, or synovial, joints*, such as the knee and the TMJ, are freely movable. Most diarthrotic joints are associated with a joint capsule containing synovial fluid. Diarthrotic joints are the most numerous in the body and are subdivided according to type of movement. *Amphiarthrotic joints* are partially movable joints whose articular surfaces are connected by cartilage, such as intervertebral joints. *Synarthrotic joints*, such as the cranial sutures, are immovable.

During endoscopic retrograde cholangiopancreatography (ERCP) examination, contrast medium is injected into the: Common bile duct

*Endoscopic retrograde cholangiopancreatography (ERCP)* is performed to diagnose disease of the biliary and/or pancreatic organs. Fluoroscopic control is used to introduce the fiber-optic endoscope through the mouth and into the duodenum. The hepatopancreatic ampulla (of Vater) then is located and cannulated, and contrast medium is injected into the common bile duct.

Graves disease is associated with: Thyroid overactivity

*Graves disease* is the most frequently occurring form of hyperthyroidism. Graves disease is an autoimmune disorder whose symptoms include enlargement of the thyroid gland and exophthalmos (protrusion of the eyes resulting from fluid buildup behind them). Hypothyroidism can result in cretinism in the child and myxedema in the adult. Adrenal overactivity produces *Cushing syndrome*; underactivity causes *Addison disease*.

Isotopes are atoms that have the same: Atomic number but a different mass number.

*Isotopes* are atoms of the same element (the same atomic number or number of protons) but a different mass number. They differ, therefore, in their number of neutrons. Atoms having the same mass number but different atomic number are *isobars*. Atoms having the same neutron number but different atomic number are *isotones*. Atoms with the same atomic number and mass number are *isomers.*

How is the thickness of the tomographic section related to the tomographic angle? The greater the tomographic angle, the thinner the section.

*Tomography* is a procedure that uses reciprocal motion between the x-ray tube and the film to image structures at a particular level in the body, while blurring everything above and below that level. The thickness of the level visualized can be varied by changing the tube angle (amplitude). In general, the greater the tube angle, the thinner the section imaged. Thinner sections may be used for imaging small or intricate structures.

What is the best position/projection to demonstrate the longitudinal arch of the foot? Lateromedial weight-bearing lateral

*Weight-bearing lateral projections of the foot* are requested often to evaluate the longitudinal arch structure of the foot. The patient stands on a small platform. The x-ray cassette is placed between the feet, in a slot provided on the platform, with the top of the cassette against the medial aspect of the foot. The CR is directed to enter the lateral aspect of the foot perpendicular to the base of the fifth metatarsal and to exit the medial side of the foot.

Which of the following is (are) associated with a Colles' fracture? Chip fracture of the ulnar styloid. Posterior or backward displacement.

A *Colles fracture* usually is caused by a fall onto an outstretched (extended) hand to "brake" a fall. The wrist then suffers an impacted transverse fracture of the distal inch of the radius with an accompanying chip fracture of the ulnar styloid process. Because of the hand position at the time of the fall, the fracture usually is displaced backward approximately 30 degrees.

A compression fracture of the posterolateral humeral head and associated with an anterior dislocation of the glenohumeral joint is called a(an): Hill-Sachs defect.

A *Hill-Sachs defect* is a compression fracture of the posterolateral humeral head, usually associated with anterior dislocation of the shoulder joint. It can involve the cartilage of the humeral head, causing instability and predisposing the shoulder to subsequent dislocations. A *Bankart lesion* is a fracture of the anteroinferior portion of the rim of the glenoid fossa. A *rotator cuff tear* involves injury to one or more of the muscles participating in formation of that muscular structure. The supraspinatus, infraspinatus, subscapularis, and teres minor are the major muscles of the rotator cuff. *Adhesive capsulitis*, or "*frozen shoulder*," causes very diminished shoulder movement as a result of chronic joint inflammation.

Which of the following equipment is necessary for ERCP? A fluoroscopic unit with imaging device and tilt-table capabilities. A fiberoptic endoscope. Polyethylene catheters.

A fluoroscopic unit with spot device and tilt table should be used for *endoscopic retrograde pancreatography*. The Trendelenburg position is sometimes necessary to fill the interhepatic ducts, and a semierect position may be necessary to fill the lower end of the common bile duct. Also necessary are a fiberoptic endoscope for locating the hepatopancreatic ampulla and polyethylene catheters for the introduction of contrast medium.

AP stress studies of the ankle may be performed: Following inversion or eversion injuries. To demonstrate a ligament tear.

After forceful eversion or inversion injuries, *AP stress studies of the ankle* are valuable to confirm the presence of a ligament tear. Keeping the ankle in an AP position, the physician guides the ankle into inversion and eversion maneuvers. Characteristic changes in the relationship of the talus, tibia, and fibula will indicate ligament injury. *Inversion stress* demonstrates the lateral ligament, whereas *eversion stress* demonstrates the medial ligament. A fractured ankle would not be manipulated in this manner.

To demonstrate the entire circumference of the radial head, the required exposure(s) must include: Epicondyles perpendicular to the IP

Although routine elbow projections may be essentially negative, conditions may exist (such as an elevated fat pad) that seem to indicate the presence of a small fracture of the radial head. To demonstrate the entire circumference of the radial head, four exposures are made with the elbow flexed 90 degrees and with the humeral epicondyles superimposed and perpendicular to the IP—one with the hand supinated as much as possible, one with the hand lateral, one with the hand pronated, and one with the hand in internal rotation, thumb down. Each maneuver changes the position of the radial head, and a different surface is presented for inspection.

Which of the following may be used as landmark(s) for an AP projection of the hip? 2 in. medial to the ASIS Prominence of the greater trochanter

For an *AP projection of the hip*, two bony landmarks are used. The CR is directed perpendicular to a point located 2 in. medial to the ASIS at the level of the greater trochanter. A point midway between the iliac crest and the pubic symphysis is too superior and medial to coincide with the hip articulation.

The AP projection of the sacrum requires the central ray to be directed: 15° cephalad to a point approximately 2 inches superior to the pubis.

For the *AP projection of the sacrum*, the patient is AP supine with the MSP perpendicular to the x-ray tabletop. The central ray is directed 15° cephalad to a point 2 inches superior to the pubis (approximately midway between the ASIS and the pubic symphysis). In this projection, the central ray angulation parallels the sacral curve and provides less distorted visualization of the sacrum and its foramina.

In the lateral projection of the knee, the central ray is angled 5° cephalad to prevent superimposition of which of the following structures on the joint space? Medial femoral condyle

For the *lateral projection of the knee*, the patient is turned onto the affected side. This places the lateral femoral condyle closest to the IR and the medial femoral condyle remote from the IR. Consequently, there is significant magnification of the medial femoral condyle and, unless the central ray is angled slightly cephalad, subsequent obliteration of the joint space.

Practice(s) that enable the radiographer to reduce the exposure time required for a particular image include: Use of a higher milliamperage Use of a higher kilovoltage Use of a faster film-screen combination

If it is desired to reduce the exposure time for a particular radiograph, as it might be when radiographing patients who are unable to cooperate fully, the milliamperage must be increased sufficiently to maintain the original milliampere-seconds value and thus radiographic density. A higher kilovoltage could be useful because it would allow further reduction of the milliampere-seconds (exposure time) according to the 15% rule. Use of a higher-speed film-screen combination also helps to reduce milliampere-seconds (exposure time) through more efficient conversion of photon energy to fluorescent light energy.

Which of the following terms is correctly used to describe x-ray beam quality? HVL

Kilovoltage (kV) and the HVL effect a change in both the quantity and the quality of the primary beam. The principal qualitative factor of the primary beam is kilovoltage, but an increase in kilovoltage will also increase the number of photons produced at the target. *HVL*, defined as the amount of material necessary to decrease the intensity of the beam to one-half, therefore changes both beam quality and beam quantity. Milliamperage is directly proportional to x-ray intensity (i.e., quantity/dose rate) but is unrelated to the quality of the beam.

An AP radiograph of the femur was made using 300 mA, 0.03 second, 76 kV, 40-in. SID, 1.2-mm focal spot, and a 400-speed film-screen system. With all other factors remaining constant, which of the following exposure times would be required to maintain radiographic density using 87 kV, a 200-speed film-screen system, and the addition of a 12:1 grid? 0.15 second

If the imaging system speed is cut in half (from 400-200 speed), the result will be half the original density on the radiograph. Therefore, to maintain the original density, the milliampere-seconds value must be doubled from the original 9-18 mAs. A 15% increase in kilovoltage was made, increasing the kilovoltage to 87 kV. Because the kilovoltage change effectively doubles the radiographic density, the milliampere-seconds value now must be cut in half (from 18-9 mAs) to compensate. Grids are used to absorb scattered radiation from the remnant beam before it can contribute to the latent image. Because the grid removes scattered (and some primary/useful photons as well) radiation from the beam, an increase in exposure factors is required. The amount of increase depends on the grid ratio: The higher the grid ratio, the higher is the correction factor. The correction factor for a 12:1 grid is 5; therefore, the milliampere-seconds value (9) is multiplied by 5 to arrive at the new required milliampere-seconds value (45). Using the milliampere-seconds equation mA × s = mAs, it is determined that 0.15 second will be required at 300 mA: 300x = 45 x = 0.15 s

To demonstrate a profile view of the glenoid fossa, the patient is AP recumbent and obliqued 45 degrees: Toward the affected side.

In an AP projection of the shoulder, there is superimposition of the humeral head and glenoid fossa. With the patient *obliqued 45 degrees toward the affected shoulder*, the glenohumeral joint is open, and the glenoid fossa is seen in profile. The patient's arm is abducted somewhat and placed in internal rotation.

Greater latitude is available to the radiographer when using: High-kilovoltage factors. A slow film-screen combination.

In the *low-kilovoltage ranges*, a difference of just a few kilovolts makes a very noticeable radiographic difference; that is, there is *little latitude*. *High-kilovoltage techniques* offer a much *greater margin for error*, as do slower film-screen combinations. Grid ratio is unrelated to exposure latitude, but higher-ratio grids offer less tube-centering latitude (i.e., leeway, margin for error) than low-ratio grids.

Which of the following will best demonstrate the lumbosacral junction in the AP position? CR cephalad 30-35 degrees

In the AP projection of the lumbar spine, the disk spaces of L1 to L4 are perpendicular to the IR and well visualized, but the L5 to S1 disk space is angled 30 to 35 degrees cephalad to the perpendicular. If the CR is directed *30 to 35 degrees cephalad midway between the ASIS and the publis symphysis*, the *L5 to S1 interspace* will be well demonstrated.

Both radiographic images seen in the figure below were made of the same subject using identical exposure factors. Which of the following statements correctly describes these images? Image B demonstrates more optical density because a shorter SID was used.

In the figure shown, image B is darker and therefore has more optical (radiographic) density. Radiographic density is significantly affected by mAs, SID, and exposure rate. In this case, there is a difference in SID between the two images. As SID decreases, exposure rate increases and radiographic density increases. Image B is darker (has more optical density) than image A because image B was exposed at a shorter SID (and therefore a higher exposure rate).

The AP axial projection of the pulmonary apices requires the CR to be directed: 15 degrees cephalad

It is occasionally necessary to view the *lung apices* free of superimposition with the clavicles. This objective can be achieved in an *AP axial projection*. The patient is positioned AP erect with the CR directed 15 degrees cephalad, entering the manubrium. An AP axial projection can also be obtained with the patient in the lordotic position. If sufficient lordosis can be assumed, the CR is directed perpendicular to the IR.

With the patient and the x-ray tube positioned as illustrated in Figure 2-2, which of the following will be visualized? Patellofemoral articulation Tangential patella

Note the relationship between the thigh, lower leg, patella, and CR. The CR is directed parallel to the plane of the patella, thereby providing a *tangential projection of the patella* (i.e., patella in profile) and an unobstructed view of the patellofemoral articulation (Figure 2-42). A *tunnel view* is required to demonstrate the intercondyloid fossa and the articulating surfaces of the tibia and femur.

Skeletal conditions characterized by faulty bone calcification include: Osteomalacia. Rickets.

Rickets and osteomalacia are skeletal disorders characterized by abnormal calcification processes. In *osteomalacia*, bones become soft and are easily misshapen. *Rickets* affects the growing bones of children and is also characterized by soft, misshapened bones—as a result of calcium salts not being deposited in bone matrix. *Osteoarthritis* is a degeneration of articular cartilage; when these surfaces then attempt to articulate and move, bone friction and pain occur.

Examples of synovial pivot articulations include the: Atlantoaxial joint Radioulnar joint

Synovial pivot joints are *diarthrotic*, that is, freely movable. *Pivot joints* permit rotation motion. Examples include the proximal radioulnar joint that permits supination and pronation of the hand. The atlantoaxial joint is the articulation between C1 and C2 and permits rotation of the head. The temporomandibular joint is diarthrotic, having both hinge and planar movements.

With the patient seated at the end of the x-ray table, elbow flexed 80 degrees, and the CR directed 45 degrees laterally from the shoulder to the elbow joint, which of the following structures will be demonstrated best? Coronoid process

The *axial trauma lateral elbow (Coyle) position* is described. If routine elbow projections in extension are not possible because of limited part movement, these positions can be used to demonstrate the coronoid process and/or radial head. With the *elbow flexed 90 degrees* and the CR directed to the elbow joint at an angle of *45 degrees medially* (i.e., toward the shoulder), the joint space between the radial head and capitulum should be revealed. With the *elbow flexed 80 degrees* and the CR directed to the elbow joint at an angle of *45 degrees laterally* (i.e., from the shoulder toward the elbow), the elongated coronoid process will be visualized.

To obtain an exact axial projection of the clavicle, place the patient: In a lordotic position and direct the central ray at right angles to the coronal plane of the clavicle.

The *exact axial projection of the clavicle* is performed by placing the patient in a lordotic position, leaning against the vertical grid device. This places the clavicle at right angles, or nearly so, to the plane of the IR. The central ray is directed to enter the inferior border of the clavicle, at right angles to its coronal plane. Other axial projections may include a prone position with a 25° to 30° caudal angle. However, none of these produce an exact axial projection of the clavicle.

Which of the following projections of the ankle would best demonstrate the distal tibiofibular joint? Medial oblique 45°

To best demonstrate the distal tibiofibular articulation, a *45° medial oblique projection of the ankle* is required. The 15° medial oblique is used to demonstrate the *ankle mortise* (joint). Although the joint is well demonstrated in the 15° medial oblique, there is some superimposition of the distal tibia and fibula, and greater obliquity is required to separate the bones.

Which of the following criteria is (are) required for visualization of the greater tubercle in profile? 1. Epicondyles parallel to the IR 2. Arm in external rotation 3. Humerus in AP position

The *greater and lesser tubercles* are prominences on the proximal humerus separated by the *intertubercular (bicipital) groove*. The *AP projection of the humerus/shoulder* places the epicondyles parallel to the IR and the shoulder in external rotation, and demonstrates the greater tubercle in profile. The *lateral projection of the humerus* places the shoulder in extreme internal rotation with the epicondyles perpendicular to the IR and demonstrates the lesser tubercle in profile.

All of the following statements regarding the inferosuperior axial (nontrauma, Lawrence method) projection of the shoulder are true: The coracoid process and lesser tubercle are seen in profile. The arm is abducted about 90° from the body. The CR is directed medially 25° to 30° through the axilla.

The *inferosuperior axial (nontrauma, Lawrence method) projection of the shoulder* demonstrates the glenohumeral joint and adjacent structures. The patient is supine with arm abducted 90°, and in external rotation. The (horizontal) CR is directed *medially 25° to 30° through the axilla*. The coracoid process and lesser tubercle are seen in profile.

Which of the following shoulder projections can be used to evaluate the lesser tubercle in profile? Internal rotation position.

The *internal rotation* position places the humeral epicondyles perpendicular to the IR, the humerus in a true lateral position, and the lesser tubercle in profile. The *external rotation* position places the humeral epicondyles parallel to the IR, the humerus in a true AP position, and the greater tubercle in profile. The *neutral position* is used often for the evaluation of calcium deposits in the shoulder joint.

In which projection of the foot are the interspaces between the first and second cuneiforms best demonstrated? Lateral oblique foot

The *lateral oblique foot* demonstrates the interspaces between the first and second metatarsals and between the first and second cuneiforms. To best demonstrate most of the tarsals and intertarsal spaces (including the cuboid, sinus tarsi, and tuberosity of the fifth metatarsal), a *medial oblique* projection is required (plantar surface and IR form a 30-degree angle). A *weight-bearing lateral* projection of the feet is used to demonstrate the longitudinal arches.

In the 45-degree medial oblique projection of the ankle, the: Tibiofibular joint is visualized Plantar surface should be vertical

The *medial oblique projection of the ankle* can be performed either as a 15- to 20-degree oblique or as a 45-degree oblique. The 15- to 20-degree oblique projection demonstrates the *ankle mortise*, that is, the articulations between the talus, tibia, and fibula. The 45-degree oblique opens the *distal tibiofibular joint*. In all three cases, although the MSP can change the plantar surface must be vertical.

In the 15° medial oblique projection of the ankle, the: Talotibial joint is visualized. Malleoli demonstrated in profile.

The *medial oblique projection of the ankle* can be performed either as a 15° to 20° oblique or as a 45° oblique. The 15° to 20° oblique demonstrates the *ankle mortise*, that is, the articulations between the talus, tibia, and fibula. The 45° oblique opens the *distal tibiofibular joint*. In all three cases, it is often recommended that the plantar surface be vertical.

Which of the following is an important consideration to avoid excessive metacarpal joint overlap in the oblique projection of the hand? Oblique the hand no more than 45 degrees.

The *oblique projection of the hand* should demonstrate minimal overlap of the third, fourth, and fifth metacarpals. Excessive overlap of these metacarpals is caused by obliquing the hand more than 45 degrees. The use of a 45-degree foam wedge ensures that the fingers will be extended and parallel to the IR, thus permitting visualization of the interphalangeal joints and avoiding foreshortening of the phalanges. Clenching of the fist and ulnar flexion are maneuvers used to better demonstrate the carpal scaphoid.

Which of the following bones participate(s) in the formation of the obturator foramen? Ischium Pubis

The *obturator foramen* is a large oval foramen below each acetabulum and is formed by the ischium and pubis. The *acetabulum* is the bony socket that receives the head of the femur to form the hip joint. The upper two-fifths of the acetabulum is formed by the ilium, the lower anterior one-fifth is formed by the pubis, and the lower posterior two-fifths is formed by the ischium. Thus, the acetabulum is formed by all three of the bones that form the pelvis—the ilium, the ischium, and the pubis.

What projection of the os calsis is obtained with the leg extended, the plantar surface of the foot vertical and perpendicular to the IR, and the CR directed 40 degrees cephalad? Axial plantodorsal projection

The *plantodorsal projection of the os calsis/calcaneus* is described. It is performed supine and requires cephalad angulation. The CR enters the plantar surface and exits the dorsal surface. The axial dorsoplantar projection requires that the CR enter the dorsal surface of the foot and exit the plantar surface.

Muscles that contribute to the formation of the rotator cuff include the: 1. Subscapularis. 2. Infraspinatus. 3. Teres minor.

The *rotator cuff* is a musculotendinous structure that includes the supraspinatus, infraspinatus subscapularis, and teres minor muscles. The muscles function to stabilize the humeral head in all arm motions and, together with the deltoid, function to abduct and rotate the arm. Weakness of the rotator cuff can lead to impingement syndrome and/or tendonitis. A tear of the cuff can result in subluxation; calcification can lead to shoulder immobilization.

The carpal scaphoid can be demonstrated in which of the following projection(s) of the wrist? PA oblique

The *scaphoid* can be difficult to image because its curved shape lends itself to foreshortening and self-superimposition. The lateral carpals, especially the scaphoid, are well demonstrated in the PA oblique projection. The ulnar flexion maneuver helps to overcome the scaphoid's self-superimposition. The scaphoid may also be demonstrated with less foreshortening with the wrist PA and elevated 20 degrees. The CR is directed perpendicular to the carpal scaphoid. The medial carpals, especially the pisiform, are well demonstrated in the AP oblique projection with the radial flexion maneuver.

Which of the following may be used to evaluate the glenohumeral joint? (All:) 1. Scapular Y projection 2. Inferosuperior axial 3. Transthoracic lateral

The *scapular Y projection* is an oblique projection of the shoulder and is used to demonstrate anterior or posterior shoulder dislocation. The *inferosuperior axial projection* may be used to evaluate the glenohumeral joint when the patient is able to abduct the arm. The *transthoracic lateral projection* is used to evaluate the glenohumeral joint and upper humerus when the patient is unable to abduct the arm.

Which of the following may be used to evaluate the glenohumeral joint? Scapular Y projection Inferosuperior axial Transthoracic lateral

The *scapular Y projection* is an oblique projection of the shoulder that is used to demonstrate anterior or posterior shoulder dislocation. The *inferosuperior axial projection* may be used to evaluate the glenohumeral joint when the patient is able to abduct the arm. The *transthoracic lateral projection* is used to evaluate the glenohumeral joint and upper humerus when the patient is unable to abduct the arm.

Which of the following statements regarding the scapular Y projection of the shoulder is (are) true? The scapular borders should be superimposed on the humeral shaft. An oblique projection of the shoulder is obtained.

The *scapular Y* projection requires that the coronal plane be about 60 degrees to the IR (MSP is about 30 degrees), thus resulting in an oblique projection of the shoulder. The vertebral and axillary borders of the scapula are superimposed on the humeral shaft, and the resulting relationship between the glenoid fossa and humeral head will demonstrate anterior or posterior dislocation. Lateral or medial dislocation is evaluated on the *AP projection*.

Tangential axial projections of the patella can be obtained in which of the following positions? Supine flexion 45° (Merchant) Prone flexion 90° (Settegast) Prone flexion 55° (Hughston)

The *tangential axial projections of the patella* are also often referred to as *"sunrise" or "skyline" views*. The *supine flexion 45° (Merchant) position* requires a special apparatus, and the patellae can be examined bilaterally. This position also requires patient comfort without muscle tension—muscle tension can cause a subluxed patella to be pulled into the intercondyler sulcus, giving the appearance of a normal patella. The two prone positions differ according to the degree of flexion employed. The *90° flexion (Settegast) position* must not be employed with suspected patellar fracture.

In which of the following tangential axial projections of the patella is complete relaxation of the quadriceps femoris required for an accurate diagnosis? Supine flexion 45 degrees (Merchant)

The *tangential axial projections of the patella* are also often referred to as *sunrise or skyline views*. The *supine flexion 45-degree (Merchant) position* requires a special apparatus, and the patellae can be examined bilaterally. This position also requires patient comfort without muscle tension—muscle tension can cause a subluxed patella to be pulled into the intercondyler sulcus, giving the appearance of a normal patella. The two prone positions differ according to the degree of flexion employed. The* 90-degree flexion (Settegast) position* must not be employed with suspected patellar fracture.

In which of the following positions can the sesamoid bones of the foot be demonstrated to be free of superimposition with the metatarsals or phalanges? Tangential metatarsals/toes

The *tangential projection* projects the *sesamoid bones* separate from adjacent structures. The patient is best examined in the prone position because this places the parts of interest closest to the IR. The affected foot is dorsiflexed so as to place its plantar surface 15 to 20 degrees with the vertical. The CR is directed perpendicular to the posterior surface of the foot (near the metatarsophalangeal joints). The *dorsoplantar and oblique projections of the foot* will demonstrate the sesamoid bones superimposed on adjacent bony structures.

Which of the following positions can be used to demonstrate the axillary ribs of the right thorax? LAO RPO

The axillary portion of the ribs is best demonstrated in a 45-degree oblique position. The axillary ribs are demonstrated in the AP oblique projection with the affected side adjacent to the IR and in the PA oblique projection with the affected side away from the IR. Therefore, the right axillary ribs would be demonstrated in the RPO (AP oblique with affected side adjacent to the IR) and LAO (PA oblique with affected side away from the IR) positions.

The first carpometacarpal joint is formed by the articulation of the base of the first metacarpal and the: Trapezium.

The bases of the proximal row of phalanges articulate with the heads of the metacarpals to form the *(condyloid) metacarpophalangeal joints*, which permit flexion and extension, abduction and adduction, and circumduction. The bases of the metacarpals articulate with each other and the distal row of carpals at the *carpometacarpal joints*. The first carpometacarpal joint (thumb) is a *saddle joint*, permitting flexion and extension, abduction and adduction, and circumduction; it is formed by the articulation of the base of the first metacarpal and the trapezium.

Which of the following articulates with the base of the fifth metatarsal? Cuboid

The bones of the foot include the seven tarsal bones, five metatarsal bones, and 14 phalanges. The *calcaneus (os calsis)* serves as the attachment for the Achilles tendon and articulates anteriorly with the cuboid bone. Articulating anteriorly with the navicular are the three cuneiform bones: medial/first, intermediate/second, and lateral/third. The navicular articulates laterally with the cuboid. The bases of the fourth and fifth metatarsals articulate with the cuboid. The fifth (most lateral) metatarsal projects laterally and presents a large tuberosity at its base making it very susceptible to fracture.

Which of the following is (are) well demonstrated in the oblique position of the cervical vertebrae? Intervertebral foramina

The cervical intervertebral foramina form a 45-degree angle with the MSP and, therefore, are well visualized in a 45-degree oblique position. Apophyseal joints are formed by articulating surfaces of the inferior articular facet of one vertebra with the superior articular facet of the vertebra below; they are well demonstrated in the lateral position of the cervical spine. The intervertebral disk spaces are best demonstrated in the lateral position.

Which of the following articulations participate in the formation of the elbow joint? Between the humeral trochlea and the semilunar/trochlear notch. Between the capitulum and the radial head. The proximal radioulnar joint.

The distal humerus articulates with the radius and ulna to form a part of the elbow joint. The lateral aspect of the distal humerus presents a raised, smooth, rounded surface, the *capitulum*, that articulates with the superior surface of the radial head. The *trochlea* is on the medial aspect of the distal humerus and articulates with the *semilunar notch* of the ulna. All three articulations are enclosed in a common capsule to form the elbow joint proper.

All the following are posterior structures: The linea aspera. The popliteal surface. The intercondyloid fossa.

The femur is the longest and strongest bone in the body. The femoral shaft is bowed slightly anteriorly. The proximal end of the femur consists of a head, which is received by the acetabulum of the pelvis. The femoral head has a small notch, the *fovea capitis femoris*, for ligament attachment. The femoral neck, which joins the head and shaft, angles upward approximately 120 degrees and forward (in anteversion) approximately 15 degrees. The greater (lateral) and lesser (medial) trochanters are large processes on the posterior proximal femur. The greater trochanter is a prominent positioning landmark that lies in the same transverse plane as the public symphysis and coccyx. The intertrochanteric crest runs obliquely between the trochanters; the intertrochanteric line runs anteriorly parallel to the crest. The femoral shaft presents a long, narrow ridge posteriorly called the *linea aspera*. Its distal anterior portion presents the patellar surface—a triangular depression over which the patella glides during flexion. The distal posterior surface presents the popliteal surface—a depression that houses the popliteal artery. The medial and lateral femoral condyles are very prominent posterior structures, and between them is the deep *intercondyloid fossa*. Just above the condyles are the medial and lateral femoral epicondyles.

The fifth metacarpal is located on which aspect of the hand? Medial

The fifth metacarpal is located on the medial aspect of the hand. Remember to always view a part in its anatomic position. With the arm in the anatomic position, the fifth metacarpal and the ulna lie medially.

What could be done to improve the mediolateral projection of the knee seen in Figure 2-3? Rotate the pelvis slightly backward/posteriorly.

The figure illustrates a *mediolateral projection of the knee*. The femoral condyles are not superimposed posteriorly, indicating incorrect degree of forward (anterior)/backward (posterior) rotation. Because the magnified medial femoral condyle is obscuring the femoropatellar articulation, the radiographer should rotate the pelvis backward, i.e. posteriorly, a bit. This will superimpose the femoral condyles, place the patella perpendicular to the tabletop, and open the femoropatellar joint space.

What should be done to better demonstrate the coracoid process shown in Figure 2-22? Angle the CR about 30 degrees cephalad.

The figure shows an *AP projection of the shoulder*. A plane passing through the epicondyles is parallel to the IR (and perpendicular to the CR). To project the *coracoid process* with less self-superimposition, the CR must be angled *cephalad 15 degrees*. The amount of cephalad angulation depends on the degree of thoracic kyphosis; the greater the degree of kyphosis, the greater is the degree of cephalad angulation required. A *30-degree angle* is used for the average patient.

With which of the following does the trapezium articulate? First metacarpal

The first metacarpal, on the lateral side of the hand, articulates with the most lateral carpal of the distal carpal row, the greater multangular/trapezium. This articulation forms a rather unique and very versatile *saddle joint* named for the shape of its articulating surfaces.

The greater tubercle should be visualized in profile in which of the following? AP shoulder, external rotation.

The greater and lesser tubercles are prominences on the proximal humerus, separated by the bicipital groove. The *AP projection of the humerus* in external rotation demonstrates the greater tubercle in profile. With the arm placed in *internal rotation*, the humerus is placed in a true lateral position and the lesser tubercle is demonstrated.

The lesser tubercle of the humerus will be visualized in profile in the: AP shoulder internal rotation radiograph.

The greater and lesser tubercles are prominences on the proximal humerus, separated by the bicipital groove. The AP projection of the humerus in *external rotation* demonstrates the greater tubercle in profile. With the arm placed in *internal rotation*, the humerus is placed in a true lateral position, and the lesser tubercle is demonstrated.

The relationship between the intensity of light striking a film and the intensity of light transmitted through the film is an expression of which of the following? Radiographic density

The greater the quantity of black metallic silver deposited on a film, the greater is the *radiographic density*. The greater the degree of radiographic density (degree of blackening), the less is the quantity of illuminator light transmitted through the film. Therefore, the relationship between the amount of illuminator light striking the film and the amount of light transmitted through the film is an expression of radiographic density. It is expressed by the formula:

Which of the following bones participate(s) in the formation of the knee joint? Femur Tibia

The knee (tibiofemoral joint) is the largest joint of the body, formed by the articulation of the femur and tibia. However, it actually consists of three articulations—the patellofemoral joint, the lateral tibiofemoral joint (lateral femoral condyle with tibial plateau), and the medial tibiofemoral joint (medial femoral condyle with tibial plateau). Although the knee is classified as a synovial (diarthrotic) hinge-type joint, the patellofemoral joint actually is a gliding joint, and the medial and lateral tibiofemoral joints are hinge type.

For an AP projection of the knee on a patient whose measurement from ASIS to tabletop is 21 cm, which CR direction will best demonstrate the knee joint? 0 degrees (perpendicular)

The knee is formed by the proximal tibia, the patella, and the distal femur, which articulate to form the femorotibial and femoropatellar joints. Body habitus will change the relationship of the knee-joint space with the tabletop/IR considerably. *AP Knee:* The CR should be directed to ½ inch below patellar apex (knee joint). The direction of CR depends on distance between the ASIS and tabletop/IR. When this *distance is up to 19 cm (thin pelvis)*, the CR should be directed *3 to 5 degrees caudad*; When the *distance is between 19 to 24 cm*, the CR is directed *vertically/perpendicular (0 degrees)*; When the *distance is greater than 24 cm (thick pelvis)*, the CR is directed *3 to 5 degrees cephalad*.

The femoral neck can be located: Perpendicular to a line drawn from the ASIS to the pubic symphysis.

The landmarks that can be used in radiography of the bony pelvis are the iliac crest, the ASIS, the pubic symphysis, the greater trochanter, the ishchial tuberosity, and the tip of the coccyx. With the patient in the anatomic position, the *femoral neck is located 2½ in. distal on a line drawn perpendicular to the midpoint of a line drawn between the ASIS and the pubic symphysis*. It is recommended to rotate the legs inward about *15 degrees*, whenever possible, to place the femoral neck parallel to the IR.

The AP axial projection, or "frog leg" position, of the femoral neck places the patient in a supine position with the affected thigh: Abducted 40 degrees from the vertical

The patient is supine with the leg abducted (drawn away from the midline) approximately 40 degrees. This 40-degree abduction from the vertical places the long axis of the femoral neck parallel to the IR. Adduction is drawing the extremity closer to the midline of the body.

Inspiration and expiration projections of the chest are performed to demonstrate: Partial or complete collapse of pulmonary lobe(s) Air in the pleural cavity Foreign body

The phase of respiration is exceedingly important in thoracic radiography because lung expansion and the position of the diaphragm strongly influence the appearance of the finished radiograph. Inspiration and expiration radiographs of the chest are taken to demonstrate air in the pleural cavity (*pneumothorax*), to demonstrate *atelectasis* (partial or complete collapse of one or more pulmonary lobes) or the degree of diaphragm excursion, or to detect the presence of a foreign body. The expiration image will require a somewhat greater exposure (6-8 kV more) to compensate for the diminished quantity of air in the lungs.

Which of the following statements regarding the radiograph in Figure A is (are) true? The tibial eminences are well visualized. The femorotibial articulation is well demonstrated.

The pictured radiograph is an *AP projection of the knee* with the knee extended. The tibial intercondylar eminences are well demonstrated on the tibial plateau, and the femorotibial joint is well visualized. The intercondyloid fossa is not demonstrated here. A *"tunnel" view* of the knee is required to demonstrate the intercondyloid fossa.

L-Spine

The posterior oblique positions (LPO and RPO) demonstrate the apophyseal joints closer to the IR, while the anterior oblique positions (LAO and RAO) demonstrate the apophyseal joints further from the IR (Fig. B). The AP projection demonstrates the lumbar bodies and disk spaces and the transverse and spinous processes. The lateral position provides the best demonstration of the lumbar bodies, intervertebral disk spaces, spinous processes, pedicles, and intervertebral foramina.

The right posterior oblique position (Judet method) of the right acetabulum will demonstrate the: Anterior rim of the right acetabulum. Right iliac wing.

The posterior oblique projection of the acetabulum (*Judet method*) requires a 45-degree obliquity of the entire MSP. In the RPO position, the *down side* (the right side in this case) will demonstrate the anterior rim of the right acetabulum, the right posterior ilioischial column, and the right iliac wing. When centered to the *up side* (left in this case), the structures demonstrated are the posterior rim of the left acetabulum, left anterior iliopubic column, and the left obturator foramen.

The right posterior oblique (RPO) position of the left acetabulum will demonstrate the: Posterior rim of the left acetabulum. Left anterior iliopubic column.

The posterior oblique projection of the acetabulum (*Judet method*) requires a 45-degree obliquity of the entire midsagittal plane (MSP). In the RPO position, the *down side* (the right side in this case) will demonstrate the anterior rim of the right acetabulum, the right posterior ilioischial column, and the right iliac wing. When centered to the *up side* (the left side in this case), the structures demonstrated are the posterior rim of the left acetabulum, the left anterior iliopubic column, and the left obturator foramen. The right iliac wing will be demonstrated in this position.

An AP oblique (lateral rotation) of the elbow demonstrates which of the following? Radial head free of superimposition Capitulum of the humerus

The radial head and neck are projected free of superimposition in the *AP oblique projection (lateral rotation) of the elbow*. The humeral capitulum is also well demonstrated in this external oblique position. The *AP oblique projection (medial rotation) of the elbow* superimposes the radial head and neck on the proximal ulna. It demonstrates the olecranon process within the olecranon fossa, and it projects the coronoid process free of superimposition.

The radiograph shown in Figure 7-12 can be produced with the: Long axis of the plantar surface perpendicular to the IR. CR 40 degrees cephalad to the base of the third metatarsal.

The radiograph illustrates a *plantodorsal projection of the calcaneus*. The patient usually is positioned with the leg extended and the long axis of the plantar surface perpendicular to the tabletop/IR. The CR is directed 40 degrees cephalad to the base of the third metatarsal. Structures that should be visualized include the sustentaculum tali, trochlear process, and calcaneal tuberosity.

In which projection of the foot are the sinus tarsi, cuboid, and tuberosity of the fifth metatarsal best demonstrated? Medial oblique foot

To best demonstrate most of the tarsals and intertarsal spaces (including the cuboid, sinus tarsi, and tuberosity of the fifth metatarsal), a *medial oblique of the foot* is required (plantar surface and IR form a 30° angle). The *lateral oblique* demonstrates the interspaces between the first and second metatarsals and between the first and second cuneiforms. *Weight-bearing lateral feet* are used to demonstrate the longitudinal arches.

Which of the following statements is (are) true with respect to the radiograph shown in Figure 2-26? This projection is performed to evaluate the scapula.

The radiograph in Figure 2-26 illustrates a *lateral projection of the scapula*. The axillary and vertebral borders are superimposed. The acromion and coracoid process are visualized; the coracoid process is partially superimposed on the axillary portion of the third rib. A *scapular Y projection* is often performed to demonstrate shoulder dislocation, but the affected arm is left to rest at the patient's side; the arm in this radiograph is abducted somewhat to better view the body of the scapula.

Below-diaphragm ribs are better demonstrated when: The patient is in the recumbent position.

The ribs below the diaphragm are best demonstrated with the diaphragm elevated. This is accomplished by placing the patient in a recumbent position and by taking the exposure at the end of exhalation. Conversely, the ribs above the diaphragm are best demonstrated with the diaphragm depressed. Placing the patient in the erect position and taking the exposure at the end of deep inspiration accomplishes this.

The functions of which body system include mineral homeostasis, protection, and triglyceride storage? Skeletal

The skeleton's design functions to protect vital internal organs such as the heart and lungs. Bone stores important minerals (e.g., calcium and phosphorus) and releases them into the blood as needed. Yellow bone marrow is composed mainly of fat cells and stores triglycerides for use as an energy reserve. The *endocrine system* is associated with hormone production; The integumentary system includes the skin that is important in protection and excretion; The muscular system is responsible for movement and heat production.

Which of the following is (are) demonstrated in the lateral projection of the thoracic spine? Intervertebral spaces Intervertebral foramina

The thoracic intervertebral (disk) spaces are demonstrated in the AP and lateral projections, although they are probably best demonstrated in the lateral projection. The thoracic apophyseal joints are 70 degrees to the MSP and are demonstrated in a steep (70-degree) oblique position. The thoracic intervertebral foramina, formed by the vertebral notches of the pedicles, are 90 degrees to the MSP. They are, therefore, well demonstrated in the lateral position.

Which of the following is (are) demonstrated in the AP projection of the thoracic spine? Intervertebral spaces

The thoracic intervertebral (disk) spaces are demonstrated in the AP and lateral projections, although they are probably best demonstrated in the lateral. The thoracic apophyseal joints are 70° to the MSP and are demonstrated in a steep (70°) oblique position. The thoracic intervertebral foramina, formed by the vertebral notches of the pedicles, are 90° to the MSP. They are therefore well demonstrated in the lateral position.

The innominate bone is located in the Pelvis.

The two *innominate bones* (os coxae) make up the pelvis. Each innominate bone is made three bones: ilium, ischium, and pubis. These three bones contribute to form the formation of the *acetabulum*. When the interior of the acetabulum is viewed, the ilium comprises its upper two-thirds, the ischium comprises its lower posterior two-thirds, and the pubis comprises the lower anterior one-third of the acetabulum.

Demonstration of the posterior fat pad on the lateral projection of the adult elbow can be caused by: Trauma or other pathology. Less than 90-degree flexion.

There are three important fat pads associated with the elbow, best demonstrated in the true *lateral projection of the elbow*. They cannot be demonstrated in the AP projection because of their superimposition on bony structures. The anterior fat pad is located just anterior to the distal humerus. The posterior fat pad is located within the olecranon fossa at the distal posterior humerus. The supinator fat pad/stripe is located at the proximal radius just anterior to the head, neck, and tuberosity. The posterior fat pad is not visible radiographically in the normal elbow. The posterior fat pad is visible in cases or trauma or other pathology and when the elbow is insufficiently flexed.

Valid evaluation criteria for a lateral projection of the forearm requires that: The radius and ulna be superimposed distally. The radial tuberosity should face anteriorly.

To accurately position a *lateral forearm*, the elbow must form a 90-degree angle with the humeral epicondyles perpendicular to the IR and superimposed. The radius and ulna are superimposed distally. Proximally, the coronoid process and radial head are superimposed, and the radial head faces anteriorly. Failure of the elbow to form a 90-degree angle or the hand to be lateral results in a less than satisfactory lateral projection of the forearm.

Which of the following is (are) valid criteria for a lateral projection of the forearm? The coronoid process and radial head should be superimposed. The radial tuberosity should face anteriorly.

To accurately position a *lateral forearm*, the elbow must form a 90° angle with the humeral epicondyles superimposed. The radius and ulna are superimposed only distally. Proximally, the coronoid process and radial head are superimposed, and the radial head faces anteriorly. Failure of the elbow to form a 90° angle or the hand to be lateral results in a less than satisfactory lateral projection of the forearm.

With the patient positioned as shown in Figure 6-13, how should the CR be directed to best demonstrate the intercondyloid fossa? 40 degrees caudad to the popliteal depression.

To demonstrate the *intercondyloid fossa*, the CR must be directed perpendicular to the long axis of the tibia (Figure 6-25). Because the knee is flexed so that the tibia forms a 40-degree angle with the IR, the CR must be directed *40 degrees caudad* to place the CR perpendicular to the long axis of the tibia. Directing the CR to the popliteal depression aligns the CR parallel with the knee joint space.

An axiolateral inferosuperior projection of the femoral neck is particularly useful: When the "cross-table" axiolateral is contraindicated. For patients with bilateral hip fractures. For patients with limited movement of the unaffected leg.

Typically, traumatic injury to the *hip* requires a cross-table (axiolateral) lateral projection. Occasionally, this projection may be contraindicated, for example, a patient with suspected bilateral hip fractures, or one who is unable to move the unaffected hip out of the way as required by the axiolateral. In these instances, the *axiolateral inferosuperior trauma projection (Clements-Nakayama method)* can be employed. The patient is recumbent with lateral surface of affected side close to table/stretcher edge. The CR is directed almost horizontally to the affected femoral neck (inferosuperior), with a *15° posterior angulation*. Correct placement and angulation of the grid cassette is essential to avoid grid cutoff.

The relationship between the ends of fractured long bones is referred to as: Apposition

Various terms are used to describe the position of fractured ends of long bones. The term *apposition* is used to describe the alignment, or misalignment, between the ends of fractured long bones. The term *angulation* describes the direction of misalignment. The term *luxation* refers to a dislocation. A *sprain* refers to a wrenched articulation with ligament injury.

When examining a patient whose elbow is in partial flexion: The AP projection requires two separate positions and exposures.

When a patient's *elbow needs to be examined in partial flexion*, the lateral projection offers little difficulty, but the AP projection requires special attention. If the AP projection is made with a perpendicular CR and the olecranon process resting on the table-top, the articulating surfaces are obscured. With the *elbow in partial flexion, two exposures are necessary to achieve an AP projection* of the elbow joint articular surfaces. *One is made with the forearm parallel to the IR (humerus elevated)*, which demonstrates the proximal forearm. The other is made with the *humerus parallel to the IR (forearm elevated)*, which demonstrates the distal humerus. In both cases, the CR is perpendicular if the degree of flexion is not too great or angled slightly into the joint space with greater degrees of flexion.

When examining a patient whose elbow is in partial flexion, how should an AP projection be obtained? With humerus parallel to IR, CR perpendicular. With forearm parallel to IR, CR perpendicular.

When a patient's *elbow needs to be examined in partial flexion*, the lateral projection offers little difficulty, but the AP projection requires special attention. If the AP radiograph is made with a perpendicular CR and the olecranon process resting on the tabletop, the articulating surfaces are obscured. With the elbow in partial flexion, two exposures are necessary. *One is made with the forearm parallel to the IR* (humerus elevated), which demonstrates the proximal forearm. The other is made with the *humerus parallel to the IR* (forearm elevated), which demonstrates the distal humerus. In both cases, the CR is perpendicular if the degree of flexion is not too great or is angled slightly into the joint space with greater degrees of flexion.

In the lateral projection of the foot, the: Plantar surface should be perpendicular to the IR. Metatarsals are superimposed.

When the *foot is positioned for a lateral projection*, the plantar surface should be perpendicular to the IR so as to superimpose the metatarsals. This may be accomplished with the patient lying on either the affected or the unaffected side (usually the affected), that is, mediolateral or lateromedial. The talofibular articulation is best demonstrated in the medial oblique projection of the ankle.

Which of the following projection(s) require(s) that the shoulder be placed in internal rotation? Lateral humerus

When the arm is placed in the AP position, the epicondyles are parallel to the plane of the cassette and the shoulder is placed in external rotation. In this position, an AP projection of the humerus, elbow, and forearm can be obtained; it places the greater tubercle of the humerus in profile. For the lateral projection of the humerus, the arm is internally rotated, elbow somewhat flexed, with the back of the hand against the thigh and the epicondyles superimposed and perpendicular to the IR. The lateral projections of the humerus, elbow, and forearm all require that the epicondyles be perpendicular to the plane of the cassette.

To obtain an AP projection of the right ilium, the patient's: Left side is elevated 40°.

When the pelvis is observed in the anatomic position, the ilia are seen to oblique forward, giving the pelvis a "basin-like" appearance. To view the *right iliac bone*, the radiographer must place it parallel to the IR by *elevating the left side about 40°* (RPO). The *left iliac bone* is radiographed in the *40° LPO oblique position*.

A flat and upright abdomen is requested on an acutely ill patient, to demonstrate the presence of air-fluid levels. Because of the patient's condition, the x-ray table can be tilted upright only 70° (rather than the desired 90°). How should the central ray be directed? Parallel to the floor.

Whenever a part is being radiographed for demonstration of air-fluid levels, the central ray must be directed *parallel to the floor*. In this example, the patient was unable to tolerate the 90° tilt of the x-ray table. If the radiographer were to compensate for this by directing the central ray perpendicular to the IR (angling 20° caudad), it is very possible that any air-fluid level would be blurred and indistinct, and would go unrecognized. Remember that air or fluid always levels out parallel to the floor. Thus, if the air-fluid level needs to be demonstrated, the central ray must also be parallel to the floor.

If 32 mAs and 50-speed screens were used to produce a particular radiographic density, what new mAs value would be required to produce the same density if the screen speed were changed to 400? 4 mAs

With all other factors remaining the same, as intensifying-screen speed increases, radiographic density increases. Radiographic density is directly proportional to intensifying-screen speed; that is, if screen speed doubles, density doubles. The formula to determine how milliampere-seconds should be corrected with screen-speed changes is: mAs1/mAs2 = SS2/SS1

For the AP projection of the scapula, the: Patient's arm is abducted at right angles to the body. Patient's elbow is flexed. Exposure is made during quiet breathing.

With the patient in the *AP scapula* position, the scapula and upper thorax are normally superimposed. With the arm abducted, the elbow flexed, and the hand usually supinated, much of the scapula is drawn away from the ribs. The patient should not be rotated toward the affected side because this causes superimposition of ribs on the scapula. The exposure is made during quiet breathing to obliterate pulmonary vascular markings.