Chapter 13 Flashcards
carpal bones
Beginning with the proximal row on the lateral aspect (thumb side), they are named scaphoid, lunate, triquetrum, and pisiform. The scaphoid is the most frequently fractured carpal bone. Continuing back toward the thumb, the distal row consists of the trapezium, trapezoid, capitate, and hamate. The capitate is the largest of the carpal bones.
olecranon process
sometimes called the funny bone or crazy bone.
There are two distal articular surfaces on the humerus:
the rounded capitulum (also called the capitellum), which articulates with the head of the radius, and the trochlea, a spool-shaped process that articulates within the semilunar notch of the ulna.
shoulder girdle
They include the scapula (shoulder blade), the clavicle (collar bone), and the proximal portion of the humerus.
Hand - posteroanterior (PA), PA oblique-lateral rotation, and lateral projections
Body position
Seated at end of table with elbow flexed 90 degrees and arm resting on the table.
Part position
PA
Hand open, fingers extended, with palmar surface in contact with IR, fingers moderately separated (Fig. 13.12).
PA oblique
From the PA, the hand is rotated laterally to place the anteromedial aspect in contact with IR. Coronal plane of hand forms a 45-degree angle with IR. Stair-step sponge is used to support and maintain position of fingers so that IP joints are clearly visualized (Fig. 13.14). Alternatively, without stair-step sponge, “modified teacup” position (named for position of hand when holding a teacup) is used when fingers are not of interest (Fig. 13.16).
Lateral
Medial aspect of hand is in contact with IR with coronal plane of hand perpendicular to IR. Thumb is positioned as for PA projection and is supported on a radiolucent sponge. Wrist will be slightly pronated (Fig. 13.18A). Fingers may be separated (fanned) to prevent superimposition, if desired (see Fig. 13.18B).
Central ray
PA and PA oblique
Perpendicular to third MCP joint.
Lateral
Perpendicular to second MCP joint.
Structures seen
Anatomy of entire hand (including fingertips), carpus, and distal radius and ulna.
PA
No overlap of metacarpals or digits (Fig. 13.13).
PA oblique
No or minimal overlay of metacarpal shafts, with some overlap of metacarpal heads and bases. IP joint spaces open (stair-step sponge, Fig. 13.15) or not well demonstrated (“modified teacup,” Fig. 13.17).
Lateral
Superimposition of second through fifth metacarpals. Superimposition of second through fifth phalanges (extension, Fig. 13.19A) or phalanges individually demonstrated (fanned, Fig. 13.19B). Thumb is seen in PA projection.
Finger - PA, PA oblique-lateral rotation, and lateral projections
Body position
Seated at end of table with elbow flexed and arm resting on table.
Part position
PA
Hand is open with palmar surface in contact with IR. Fingers are moderately separated (Fig. 13.21).
PA oblique
From the PA, hand is rotated lateral to place anteromedial (palmar/ulnar) surface in contact with IR. Coronal plane of fingers is at a 45-degree angle to IR. Fingers are supported by stair-step sponge (Fig. 13.23). (The alternative to the use of a stair-step sponge is the “modified teacup” position, as shown for examination of the hand.)
Lateral
Medial or lateral surface of hand may be in contact with IR, depending on which brings finger of interest nearest to IR. Other fingers are flexed or extended as necessary to leave affected finger free of superimposition. Affected finger is supported parallel to IR (Figs. 13.25, 13.27 to 13.29).
Central ray
Perpendicular to proximal IP joint.
Structures seen
Entire digit and distal portion of metacarpal with IP and MCP joint spaces open and clearly visualized (Figs. 13.22, 13.24, and 13.26). Department protocol may require including an adjacent digit in each image.
Thumb - AP, PA oblique, and lateral projections
Body position
AP
Seated at end of table, leaning forward, arm abducted 90 degrees, with forearm rotated internally into exaggerated degree of pronation.
PA oblique and lateral
Seated at end of table with elbow flexed 90 degrees, arm fully supported, and palm resting on the IR.
Part position
AP
Dorsal surface of thumb is in contact with IR. Coronal plane of thumb is parallel to IR. Plane of palm of hand is perpendicular to IR (Fig. 13.30).
PA oblique
Palmar surface of hand is in contact with IR as for PA projection of hand. Coronal plane of thumb will be 45 degrees to plane of IR (Fig. 13.32).
Lateral
Beginning with hand positioned for PA oblique thumb, patient flexes MCP joints 2 through 5 with the fingers extended, “tenting” hand until thumb is in lateral position (Fig. 13.34).
Central ray
Perpendicular to first MCP joint.
Structures seen
Entire thumb and first metacarpal with all joint spaces open and clearly visualized (Figs. 13.31, 13.33, and 13.35).
Wrist - PA, PA oblique-lateral rotation, and lateral projections
Body position
Seated at end of table with elbow flexed 90 degrees and forearm resting on table.
Part position
PA
Anterior surface of wrist is in contact with IR. Fingers are flexed to form a loose fist, placing wrist in firmer contact with IR and opening intercarpal joints (Fig. 13.38).
PA oblique
Anteromedial surface of wrist is in contact with IR so that coronal plane of wrist forms a 45-degree angle with IR. Position may be supported by wedge sponge, stair-step sponge, or patient’s thumb (Fig. 13.40).
Lateral
Medial surface of wrist is in contact with IR. Coronal plane of wrist is perpendicular to IR (Fig. 13.42).
Central ray
Perpendicular to the midcarpal area.
Structures seen
Distal portion of radius and ulna, carpal bones, and proximal halves of metacarpals (Figs. 13.39, 13.41, and 13.43).
Forearm - AP and lateral projections
Body position
Seated at end of table with axilla (armpit) at table level; this may be achieved by lowering seat or by having patient lean toward table.
Part position
AP
Arm is fully extended with hand supinated and posterior surface in contact with IR. Both wrist and elbow are supinated with coronal plane of arm parallel to IR (Fig. 13.52). This is achieved by adjusting the coronal plane of the humeral epicondyles parallel to the plane of the IR. A small sandbag in palm of hand can aid in maintaining position.
Lateral
Elbow is flexed 90 degrees with medial surface in contact with IR. Wrist is in lateral position (Fig. 13.54).
Central ray
Perpendicular to midpoint of the forearm.
Structures seen
Entire forearm, including both elbow and wrist joints (Figs. 13.53 and 13.55).
Elbow - AP and lateral projections
Body position
Seated at end of table with axilla at level of table, as for AP forearm.
Part position
AP
Arm is fully extended with hand supinated and posterior surface in contact with IR. Coronal plane of humeral epicondyles parallel to IR (Fig. 13.56). If patient is unable to fully extend arm, substitute alternate positions for AP projection with flexed elbow.
Lateral
Elbow is flexed 90 degrees with medial surface in contact with IR. Coronal plane of humeral epicondyles perpendicular to IR. Wrist is in lateral position to degree patient can achieve (Fig. 13.58).
Central ray
Perpendicular to elbow joint. For AP projection, joint is midway between humeral epicondyles. For lateral projection, it is at lateral epicondyle.
Structures seen
Elbow joint with portions of distal humerus and proximal forearm (Figs. 13.57 and 13.59).
Humerus - AP and lateral projections
Body position
Seated or standing with back to upright Bucky or grid cabinet. The body position, whether oblique or facing toward or away from the IR, is not critical as long as the epicondyles are oriented appropriately for the projection.
Part position
Adjust the height of the IR to place its upper margin about 1.5 inches (3.8cm) above the head of the humerus.
AP
Arm slightly abducted with palm of hand supinated. Coronal plane of humeral epicondyles parallel to IR (Fig. 13.68).
Lateral
Elbow flexed approximately 45 degrees and palm of hand against hip so that fingertips point down and elbow is lateral with coronal plane of humeral epicondyles perpendicular to IR (Fig. 13.69).
Central ray
Perpendicular to midhumerus.
Structures seen
Entire humerus, shoulder joint, and elbow joint (Figs. 13.72 and 13.73).
Shoulder - AP projections with both internal and external humerus rotation
Body position
Standing or seated with back to upright Bucky or grid cabinet or supine on table; coronal plane of body parallel to IR.
Part position
External rotation
Arm slightly abducted with palm of hand supinated. Arm adjusted to place coronal plane of humeral epicondyles parallel to IR (Figs. 13.74 and 13.76).
Internal rotation
Humerus and arm rotated internally until back of hand is against thigh. Arm adjusted to place coronal plane of humeral epicondyles perpendicular to IR (Figs. 13.75 and 13.77).
Central ray
Perpendicular to a point 1 inch inferior to coracoid process.
Structures seen
Entire clavicle and scapula and proximal third of humerus. External rotation demonstrates greater tubercle in profile (Fig. 13.78); internal rotation demonstrates lesser tubercle in profile (Fig. 13.79).
Shoulder - AP Oblique Projection (Grashey Method)
Body position
Patient upright or recumbent. Coronal plane of body aligned 35 to 45 degrees with respect to IR (Fig. 13.80).
Part position
Posterolateral aspect of shoulder in contact with upright Bucky or table; scapular body parallel to IR; arm in internal, external, or neutral rotation.
Central ray
Perpendicular through glenohumeral joint, at a point 2 inches (5cm) medial and 2 inches (5cm) inferior to superolateral border of shoulder.
Structures seen
Glenohumeral joint with open joint space and glenoid process in profile; coracoid process will usually obscure superior aspect of joint space (Fig. 13.81).
Shoulder - AP and transthoracic lateral or PA oblique (scapular Y) projections
Body position
Standing or seated at upright Bucky or grid cabinet.
Part position
AP
With back to upright Bucky and without moving arm. Coronal plane of body is parallel to IR (Fig. 13.82).
Transthoracic lateral
Coronal plane of body is perpendicular to IR with affected side against upright Bucky. Unaffected arm is raised above head (Fig. 13.84).
PA oblique (scapular Y)
Anterolateral aspect of shoulder against upright Bucky. Coronal plane of body 45 to 60 degrees to IR. Body rotation adjusted to place scapular body perpendicular to IR (Fig. 13.86).
Central ray
Perpendicular to center of IR, with top of IR 1.5 inches to 2 inches above top of shoulder.
Patient instruction
AP and PA oblique
Stop breathing. Do not move.
Transthoracic lateral
Use “breathing technique.” (Exposure is made during slow, deep breathing. This technique effectively blurs superimposing rib and lung structures, improving visualization of humerus.)
Structures seen
Proximal half of humerus and portions of scapula and clavicle (Figs. 13.83, 13.85, and 13.87).
Clavicle - upright PA and PA axial projections, or recumbent AP and AP axial projections
Body position
Upright
Standing or seated facing Bucky with coronal plane parallel to IR. Head turned away from side of interest. Arm at side (Figs. 13.88 and 13.89).
Recumbent
Supine (Figs. 13.90 and 13.91).
Part position
See body position.
Central ray
PA or AP
Perpendicular to midclavicle.
PA axial
15 to 30 degrees caudad to midclavicle.
AP axial
15 to 30 degrees cephalad to midclavicle.
Structures seen
Entire clavicle and its articulations (Figs. 13.92 and 13.93).
