Rad Tech Ch.13

Identify three bony prominences of the scapula

Acromion Coracoid process Superior angle Inferior angle

Is the ulna medial or lateral to the radius?

medial to the radius

The most common type of chronic degenerative joint disease that causes hypertrophy of the bone is

osteoarthritis

The PA projection of the wrist in ulnar deception is an advantageous addition to the routine wrist series in cases of suspected

scaphoid fracture

The bony landmark for wrist positioning that is a prominence on the lateral aspect of the wrist is the

styloid process of the radius

A PA projection of the shoulder region in which the central ray is directed 30 degrees caudal is taken to demonstrate

the clavicle

When performing an AP projection of the shoulder, what is the orientation of the coronal plane of the humeral epicondyles to achieve internal rotation of the humerus?

Humerus and arm rotated internally until back of hand is against thigh. Arm is adjusted to place coronal plane of humeral epicondyles perpendicular to IR.

To demonstrate a suspected fracture or dislocation in the shoulder region, the radiographic examination should consist of two projections: an AP taken with the coronal plane of the body parallel to the IR and an

PA oblique projection (scapular Y)

What are the amount and direction of central ray angulation for an AP axial projection of the clavicle?

15 to 30 degrees cephalad

What is the minimum source-image receptor distance (SID) used for nearly all radiographic images of the upper limb?

40 inches

What projections will be performed for an examination of the clavicle?

A routine clavicle study consists of PA and PA axial projections to place the clavicle as close to the IR as possible. If the patient is recumbent, a supine position may be more comfortable and AP and AP axial projections would be performed

Describe the difference between a routine shoulder examination and an examination for an acute injury

A routine shoulder examination consists of two AP projections, one with the humerus in internal rotation and one with external rotation. Examination for acute injury includes an AP projection with no rotation of the humerus and a PA oblique (scapular Y) or transthoracic lateral projection. The trauma positions are designed to show the humerus in two projections at right angles to each other without rotating the injured arm, which could cause both extreme pain and further injury

What is the amount of lateral rotation needed to achieve a PA oblique projection of the hand?

Coronal plane of hand forms 45-degree angle with IR

Describe the positioning details for the PA projection of the wrist

Anterior surface of wrist is in contact with IR. Fingers are flexed to form a loose fist, placing wrist in close contact with IR and opening intercarpal joints

Describe the positioning details for the AP projection of the forearm

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. 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

Describe the positioning details for the AP projection of the elbow

Arm is fully extended with hand supinated and posterior surface in contact with IR. Coronal plane of humeral epicondyles parallel to IR

When performing an AP projection of the shoulder, what is the orientation of the coronal plane of the humeral epicondyles to achieve external rotation of the humerus?

Arm slightly abducted with palm of hand supinated. Arm adjusted to place coronal plane of humeral epicondyles parallel to IR.

Describe the positioning details for the AP projection of the humerus.

Arm slightly abducted with palm of hand supinated. Coronal plane of humeral epicondyles parallel to IR.

List three general types of non traumatic pathology that may affect the bones of the upper limb

Bursitis Tendonitis Osteoarthritis

Name the articular processes of the distal humerus

Capitulum (lateral humerus) Trochlea (medial humerus)

What is the degree of flexion needed for the lateral projection of the elbow

Elbow is flexed 90 degrees

List two ways in which an examination of the thumb differs from an examination of a finger

For the thumb, the AP projection is preferred to the PA projection. The thumb is oblique when the hand is pronated, but the fingers are in the PA position. Examination of the thumb must include the entire first metacarpal, but examinations of the fingers need only include a portion of their respective metacarpals.

Describe the positioning details for the PA oblique projection of the fourth (ring) finger

From the PA, hand is rotated lateral to place anteromedial (palmar/ulnar) surface in contact with IR. Coronal plane of fingers at 45-degree angle to IR. Fingers are supported by stair-step sponge.

Describe the positioning details for the PA projection of the hand

Hand open, fingers extended, with palmar surface in contact with IR, fingers moderately separated

Describe the positing details for the lateral projection of the wrist

Medial surface of wrist is in contact with IR. Coronal plane of wrist is perpendicular to IR

List and describe four commonly seen fractures of the upper limb

Mentioned in the text were boxer's fracture (fifth metacarpal), occult fracture of the scaphoid, Colles fracture (distal radius), Monteggia fracture (ulnar fracture with radial head displacement), radial head fracture, and clavicle fracture.

Demonstrate and describe possible arm positions for a lateral projection of the scapula, and identify the anatomy visualized on each

Positioning the arm behind the back gives a superior view of the acromion and coracoid processes but sometimes results in superimposition of the humerus over the body of the scapula. Positioning the arm overhead provides an unobstructed view of the body, but the humeral head superimposes the superior structures of the scapula. Positioning the arm across the chest also compromises visualization of the superior structures but is often the only position attainable by the patient with a scapular injury

When performing a lateral projection of the right scapula, the position of the torso in relation to the IR is

RAO

Name a carpal bone that articulates with the first metacarpal

The carpal bone that articulates with the first metacarpal is the trapezium.

Describe the differences in positioning for a PA wrist projection and PA hand projection

The fingers are extended for a PA projection of the hand, but they are flexed into a loose fist for a PA projection of the wrist. The hand projection is centered at the third MP joint, whereas the wrist is centered midway between the styloid processes (midcarpus)

Name the middle of the third digit

The middle bone of the third digit is the middle phalanx of the third digit.

Why is it necessary to attach weights to the patients wrist when performing radiography of the acromioclavicular joints?

The purpose of attaching weights to the patient's wrists is to determine ligament integrity (a separation of the AC joint) by demonstrating change in relative positions of the acromion and clavicle when under stress.

Why is the PA projection not the routine projection for the thumb?

The resulting image will have less detail than the AP projection image because the increased object-image receptor distance (OID) results in greater magnification distortion (geometric unsharpness).

Name two special projections used specifically to demonstrate the scaphoid

Ulnar deviation Stecher method

Bilateral projections of the shoulders, with and without weights, are used to demonstrate

acromioclavicular separation

The fat pad sign may be the only radiographic indication of

an elbow fracture

When the limited operator positions the hand for a PA oblique projection using the "modified teacup" position, the anatomic aspect of the head in contact with the IR is

anteromedial

The projections that constitute a routine examination of the forearm are

anteroposterior (AP) and lateral

The head of the radius articulates with the rounded process of the distal humerus that is called the

capitulum

The long, narrow bone located anterior to the upper portion of the rib cage and commonly known as the collarbone is the

clavicle

When performing a lateral projection of the elbow, it is important to

flex the elbow 90 degrees place the central ray perpendicular to the region of the lateral epicondyle place the coronal plane of the humeral epicondyles perpendicular to the IR

The small, long bones of the digits are called

phalanges

AP projections centered inferior and medial to the coracoid process, with the humerus in both internal and external rotation, constitute a routine examination of the

shoulder girdle

The use of a stair-step sponge for a posteroanterior (PA) oblique projection of the hand, when the fingers are of interest, provides better

visualization of the interphalangeal joints