Chapter 5



Chapter 5

Shoulder Girdle

Darv Nomann R.T. (R)

Lesson 1

Anatomy and Procedures of the Shoulder Girdle

Shoulder Girdle

Consists of

Clavicle

Scapula

Articulates with

Head of humerus (shoulder joint)

Manubrium of sternum (SC joint)

Each other (AC joint)

Functions to connect the upper limb to the trunk of the body

Articulation of the upper limb with the girdle

Humerus is not considered to be part of the shoulder girdle

Because the upper portion articulates with the shoulder girdle, proximal humeral anatomy is considered in evaluation of radiographs of the shoulder joint

Shoulder joint

Diarthrodial classification by function

Synovial classification by anatomy (structure)

Ball and socket type, capable of all motions

Clavicle

Classified as a long bone

Lies just above the first rib

Acromial extremity (lateral end) articulates with acromion on scapula (AC joint)

Sternal extremity (medial end) articulates with manubrium of sternum (SC joint)

Double curve to body

Curve more pronounced in males than in females

Scapula

Classified as a flat bone

Forms the posterior portion of the shoulder girdle

Triangular in shape

General Procedural Guidelines

Shoulder, Proximal Humerus, AC joints, Clavicle, and Scapula

Patient preparation

General patient position

IR size

SID

ID markers

Radiation protection

Patient instructions

Patient Preparation

Patient preparation for shoulder girdle procedure requires removal of radiopaque artifacts from the anatomy of interest

Examples: jewelry, artifacts on clothing (e.g., bra hooks, buttons)

Secure all patient possessions in designated manner and location

General Patient Position

Shoulder procedures can be performed in erect or recumbent positions

Consider patient comfort first

IR Size

Textbook gives most common IR sizes used for shoulder girdle procedures

Collimated field generally open to size of IR

SID

SID is standardized as a part of procedural protocol

When SID is not specified under a projection, Merrill’s Atlas recommends 48˝ (122 cm)

ID Markers

Consider the use of lead to absorb scatter and how it affects side marker placement

Radiation Protection

Shield pediatric patients and patients of reproductive age

Refer to guidelines on p. 175, Volume 1

Other radiation protection measures

Close collimation

Optimum technique factors

Patient Instructions

Explain and demonstrate positions and breathing instructions

Respirations suspended for most exposures

Transthoracic lateral projection may use breathing technique

Low mA with long exposure time

Radiographic Procedures

Essential Projections: Shoulder

AP projections

Internal rotation

External rotation

Neutral position

Transthoracic lateral (Lawrence)

Inferosuperior axial (Lawrence)

PA oblique (scapular Y)

AP oblique (Grashey)

AP Projection in Internal Rotation

Patient position

Rotate patient slightly toward affected shoulder

Place body of scapula parallel with plane of IR

Important for patients with extreme kyphosis (humpback curvature of the spine)

Part position

Flex elbow slightly

Rotate arm internally and rest back of hand on hip

Place humeral epicondyles perpendicular to IR

Central ray (CR)

Perpendicular

Enters patient 1˝ inferior to coracoid process

AP Projection in External Rotation

Patient position

Rotate patient slightly toward affected shoulder

Place body of scapula parallel with plane of IR

Important for patients with extreme kyphosis (humpback curvature of the spine

Part position

Flex elbow slightly

Rotate arm externally and supinate hand

Place humeral epicondyles parallel to IR

CR

Perpendicular

Enters patient 1˝ inferior to coracoid process

AP Projection in Neutral Position

For trauma cases

Leave arm in neutral position

If possible, have patient rest the palm of the hand against the thigh

Places epicondyles at 45-degree angle to IR

CR directed the same as for other positions

Transthoracic Lateral (Lawrence)

Note: Projection used for trauma patients who cannot abduct arm

Patient position

Supine or upright lateral

Affected limb closer to IR

Unaffected limb elevated over head

Transthoracic Lateral (Lawrence)

Part position

Do not move injured limb

Insure elevated shoulder is higher than injured shoulder

Center surgical neck of humerus to IR

Transthoracic Lateral (Lawrence)

CR

Perpendicular

Enters midcoronal plane at surgical neck

If shoulders are in same plane, CR angled 10 to 15 degrees cephalad

Inferosuperior Axial Projection (Lawrence Method)

Patient position

Supine

Head and shoulder elevated on 3˝ radiolucent support

Turn head away from CR

Inferosuperior Axial Projection (Lawrence Method)

Part position

Abduct arm to right angle

If possible, place arm in external rotation

Place IR crosswise on table (in a holder) centered to shoulder joint

Inferosuperior Axial Projection (Lawrence Method)

CR

Horizontal

Medial angulation of 15 to 30 degrees

Enters axilla; passes through AC joint

Angle depends on abduction of humerus

More abduction = greater angle

PA Oblique (Scapular Y)

So named because when properly positioned, the acromion and coracoid process form a Y-shape

Position is particularly useful to diagnose shoulder dislocations

In the normal shoulder, the humeral head is directly superimposed over the junction of the Y (acromion and coracoid)

Patient position

Upright, 45 to 60 degrees anterior oblique position

Affected shoulder closer to IR

Part position

Arm position is not critical

Maintain patient comfort

CR

Perpendicular to scapulohumeral joint

AP Oblique (Grashey)

Patient position

35 to 45 degrees posterior oblique position

Affected shoulder closer to IR

More rotation may be necessary if patient is recumbent

Rotation should place scapula parallel to IR

Head of humerus will be in contact with IR

Part position

Abduct arm and slightly internally rotate

Place palm of hand on abdomen

CR

Perpendicular to glenoid cavity

Enters 2˝ (5 cm) medial and inferior to superolateral border of shoulder

Radiologic Procedures

Essential Projections: AC Joints

AP projection (Pearson method)

Patient position

Upright required because supine position will reduce dislocation, if present

Part position

Arms hanging by side, unsupported

Shoulders in same horizontal plane

Separate exposures made

One without patient’s arms weighted

One with weights affixed to patient’s arms

CR

Perpendicular to midline of body at level of AC joints if bilateral image

Perpendicular to AC joints if separate images required

Radiologic Procedures

Essential Projections: Clavicle

AP

PA

AP axial

PA axial

Note: PA projections preferred due to reduced OID and improved image quality. AP projections used on recumbent patients.

AP Clavicle

Patient position

Upright or supine

Part position

Clavicle centered to IR

Arms at sides

Shoulders in same horizontal plane

CR

Perpendicular to midshaft of clavicle

PA Clavicle

Patient position

Standing or seated upright facing vertical Bucky

Center clavicle to the midline of the Bucky

Part position

Arms relaxed by patient’s side

Shoulders placed in same transverse plane

CR

Perpendicular

Exits midshaft of the clavicle

AP Axial Clavicle

Patient position

Upright, lordotic position, if possible

If lordotic position not possible, supine with shoulders in same plane

Part position

Center clavicle to center of IR

CR

Lordotic position – 0 to 15 degrees cephalic

Supine position – 15 to 30 degrees cephalic

Amount of angle varies with patient thickness

Thinner patients = more angle

Enters midshaft of clavicle

PA Axial

Position patient as for PA projection

CR

15 to 30 degrees caudal to the supraclavicular fossa and the midshaft of the clavicle

Radiologic Procedures

Essential Projections: Scapula

AP

Lateral

AP Scapula

Patient position

Consider patient comfort first

Center affected scapula to grid

Part position

Abduct arm to right angle

Flex elbow

CR

Perpendicular to point 2˝ (5 cm) inferior to coracoid process

Lateral Scapula

Patient position

45 to 60 degrees anterior oblique position

Posterior oblique positions can be used, but scapula will be magnified

Affected scapula in contact and centered to grid

Part position – to demonstrate acromion and coracoid

Flex elbow and place back of hand on posterior thorax

Adjust to ensure humerus does not overlap scapula

OR

Bring arm across anterior thorax and grasp opposite shoulder

Part position – to demonstrate body

Extend arm upward and rest forearm on head

OR

Bring arm across anterior chest and grasp opposite shoulder

CR

Perpendicular to mid medial border of scapula

Lesson 2

Image Critique for Essential Projections of the Shoulder Girdle

Shoulder Projections

AP Projection in External Rotation

Greater tubercle in profile on lateral side of humerus

Humeral head in profile

Scapulohumeral joint seen with slight overlap of humeral head on glenoid cavity

Collimated field should include superior scapula, lateral half of clavicle, and proximal humerus

Outline of lesser tubercle seen between humeral head and greater tubercle

Soft tissue and bony trabeculae clearly demonstrated

AP Projection/Neutral Position

Humeral head should be seen in partial profile

Greater tubercle will partially superimpose the humeral head

Some overlap of the humeral head and glenoid should be seen

Collimation should include superior scapula, lateral half of clavicle, and proximal humerus

Soft tissue and bony details should be visualized

AP Projection in Internal Rotation

Collimated field includes superior scapula, lateral half of clavicle, and proximal humerus

Lesser tubercle seen in profile and pointing medially

Outline of greater tubercle superimposing humeral head

Humeral head overlaps glenoid fossa more than in external rotation and neutral positions

Soft tissue around shoulder and bony trabeculation clearly demonstrated

Transthoracic Lateral (Lawrence)

Proximal humerus demonstrated

Scapula, clavicle, and humerus seen through lung field

Scapula superimposed on T-spine

Unaffected clavicle and humerus above shoulder of interest

Inferosuperior Axial Projection(Lawrence)

Scapulohumeral joint with slight overlap

Coracoid process pointing anteriorly

Lesser tubercle in profile and pointing anteriorly

AC joint, acromion, and acromial end of clavicle projected through humeral head

Soft tissue and bony detail demonstrated

PA Oblique (Scapular Y)

Scapular body should not overlap thorax

Acromion seen laterally and free of superimposition

Coracoid process superimposed on or slightly below clavicle

Scapula in lateral profile

Humeral head will be seen

Superimposed on Y in normal shoulder

Below the coracoid process when shoulder joint is anteriorly dislocated

Below the acromion when shoulder joint is posteriorly dislocated

AP Oblique (Grashey)

Open joint space between humeral head and glenoid

Glenoid cavity in profile

Soft tissue at scapulohumeral joint

Trabecular detail on glenoid and humeral head

Image Critique Criteria

AC Joints

AP (Pearson)

AC joints seen with soft tissue and without excessive density

Both AC joints, with and without weights, included on one or two radiographs

Patient’s body not rotated or leaning

Side markers and weight or nonweight markers

Separation, if present, seen on image with weights

Image Critique Criteria

Clavicle Projections

AP/PA Clavicle

Entire clavicle centered in collimated field

Uniform density

Lateral half of clavicle above scapula and medial half superimposing thorax

AP/PA Axial Clavicle

Most of clavicle projected above ribs and scapula

Medial end overlaps first or second rib

Clavicle horizontal

Entire clavicle, AC joints, and SC joints demonstrated

AP Scapula

Lateral part of scapula free of superimposition of ribs

Scapular horizontal and not obliqued

Scapular detail seen through lung and ribs

Acromion process to inferior angle demonstrated

Lateral Scapula

Lateral and medial borders superimposed

No superimposition of scapular body on ribs

Humerus does not superimposed area of interest

Acromion to inferior angle demonstrated

Lateral thickness of scapula with proper density

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