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SIM KIAN TZEJURU X-RAY

SARAWAK GENERAL HOSPITAL

UPDATE FOR

RADIOGRAPHER

FATPAD

SIGN

Fat Pad Sign and Joint effusion

• Normal lateral view of the elbow flexed in 90° - a fat pad is seen on the anterior aspect of the joint. This is normal fat located in the joint capsule. - on the posterior side no fat pad is seen since the posterior fat is located within the deep intercondylar fossa.

Fat Pad Sign and Joint effusion

Positive fat pad signDistention of the joint will cause the anterior fat pad to become elevated and the posterior fat pad to become visible.An elevated anterior lucency and/or a visible posterior lucency on a true lateral radiograph of an elbow flexed at 90° is described as a positive fat pad sign

FAT PAD SIGN

FAT PAD SIGN

FAT PAD SIGN

TWO (2) LINES

ANTERIOR HUMERAL LINEPROXIMAL RADIAL/RADIOCAPITELLAR LINE

KURSUS POS BASIK TRAUMA RADIOGRAFI KKM20 -24 NOVEMBER 2006

Normal Elbow Anatomy

• Anterior humeral line: a line drawn parallel to the anterior humerus should pass through the middle third of the capitulum.

• Proximal radial/Radiocapitellar line: a line along the longitudinal axis of the radius should pass through the center of the capitelum in all projections.

Lateral view of elbow with anatomical lines

Normal Elbow Anatomy

• Radiocapitellar lineA line drawn through the long axis of the radius should always point toward the centre of the capitellum whatever the positioning of the patient, since the radius articulates with the capitellum (figures A-D, even when not well positioned. Notice supracondylar fracture on B.

• In dislocation of the radius this line will not pass through the centre of the capitellum.

Supracondylar fractures

A: The anterior humeral line passes through the anterior third of the capitellum and in B even more anteriorly. Notice positive posterior fat pad sign in both cases

BACK TO BASIC

ELBOW AP

• Affected arm extended

• Posterior aspect of entire limb in contact with cassette

• Palm of hand facing upwards

• Centering point 2.5 cm distal to midline between epicondyles of humerus

ELBOW AP CRITERIA OF GOOD IMAGE

• Include distal humerus,elbow joint space & proximal rad/ulna

• Radial head, neck & tuberosity slightly superimposed over proximal ulna

• Elbow joint open & in center

• Humeral epicondyles not rotated

ELBOW AP MODIFIED

ELBOW AP MODIFIED

ELBOW AP MODIFIED

Common errors in positioning Shoulder higher than elbow

For a true lateral view the shoulder should be at the level of the elbow. If the shoulder is higher than the elbow the radius and capitellum will project on the ulna. The solution is either to lift the examination table which will lift the elbow or to lower the shoulder by placing the patient on a smaller chair.

ELBOW LATERAL

• Elbow flex 90º • Hand and wrist in

lateral position• Entire arm same

plane• Center at lateral

epicondyle of humerus

ELBOW LATERAL CRITERIA OF QUALITY IMAGE

• Humeral epicondyle superimposed

• Radial head partially superimposed on coronoid process

• Olecranon process in profile

• Humeroulna joint space sharply outline

Common errors in positioning : Wrist lower than elbow

The wrist should be as high or even higher than the elbow depending on the normal valgus position of the elbow. The hand should be with the 'thumb up'.If the wrist is at a low position the humerus will rotate because the radius at the level of the wrist is lower than at the level of the elbow.

Incidence and Location of Elbow Injuries

ADULTS• Radial neck 50% • Olecranon 20%• Supracondylar 10%• Fracture/dislocat 15%

CHILDREN• Supracondylar

60%• Lateral condyle

15%• Medial epicondyle

10%• Radial neck• olecranon

Fractures of The Elbow:Distal Humerus fractures

Supracondylar fractures• Most common fracture to occur around the elbow in children• Transverse or oblique through the distal humerus above the condyles• Usually distal fracture fragment displaces posteriorly

Supracondylar fractures

Supracondylar fractures

A: The anterior humeral line passes through the anterior third of the capitellum and in B even more anteriorly. Notice positive posterior fat pad sign in both cases

Fracture of the Radial head

•Most commonly caused by a fall on an outstretched arm. •Most common elbow fracture in adults. •Radial head fractures can be very subtle and the fracture line may occasionally not be visible on the radiograph. Non-displaced radial head fractures are especially difficult to observe on plain films. •Look carefully for a visible posterior fat pad sign. This indicates an elbow effusion. Fractures of the radial head may only be detectable by this fat pad sign. The anterior fat pad may also be useful, particularly when it has the appearance of a sail, termed the sail sign. •When there is strong clinical suspicion for a radial head fracture but a fracture is not apparent on a standard projection, a radial head view or CT may aid in diagnosis.  In an adult patient with elbow effusion after trauma, radial head fracture should be highly suspected or even assumed.

Lateral view of elbow showing sail sign

FAT PAD SIGN

• sail sign

Left: both anterior and posterior fat pad signs are present. This should increase suspicion of a fracture. However, no fracture is apparent in this radiograph. Right: A different view taken from the same patient. In this view the radial head fracture is apparent.

Fracture of the Radial head

Radial head-capitellum view

• A variant of lateral projection

•Overcome the major limitation of the standard lateral view

•Projecting the radial head ventrad, free of overlap by the coronoid process

•Clearly demonstrate radial head, capitellum, both the humeroradial and humeroulnar articulations

•Subtle fractures of these structures obscurred on other projections

Fracture of the Radial head

AP and Lat views of elbow: markedly communited and displaced fracture of radial head.

Fracture of the Radial head

Dislocation of The Elbow

• Most common dislocation in children• 3rd most common dislocation in adult after shoulder and

interphalangeal joints of fingers respectively• >50% have associated fractures – most common medial

epicondyle and radial head/neck• Classified according to displacement of radius and ulna

relative to the humerus: posterior, postero-lateral, anterior, medial and anteromedial

• Practically in all elbow dislocations, both ulna and radius will be displaced

Dislocations of the Radial head

LEFT: an obvious radial dislocation. No fracture of the ulna (Monteggia) was foundRIGHT: a subtle radial head dislocation. Associated olecranon fracture is seen on carefull inspection

Dislocation of The Elbow

• Posterior and Posterolateral Dislocation

• Most common dislocations of elbow (85-90%)

• Small % of posterior dislocation will develop posttraumatic myositis ossificans at anterior aspect of joints

• Dislocated elbow with avulsion of the medial epicondyle. In this case the epicondyle is not retracted into the joint.

Dislocation of The Elbow

Fracture radial head

DO YOU SEE ANY FRACTURE?

NO FRACTURE ?

Repeat radiograph 2 weeks -Fracture epiphysis of radial head

Elbow dislocation

Fracture lateral condyle of Humerus

Fracture medial epicondyle of Humerus

Fracture radial head

Supracondylar fracture

conclusion

conclusion

ELBOW LATERAL

• Elbow flex 90º • Hand and wrist in

lateral position• Entire arm same

plane• Center at lateral

epicondyle of humerus

ELBOW LATERAL CRITERIA OF QUALITY IMAGE

• Humeral epicondyle superimposed

• Radial head partially superimposed on coronoid process

• Olecranon process in profile

• Humeroulna joint space sharply outline

Normal Elbow Anatomy

• Radiocapitellar lineA line drawn through the long axis of the radius should always point toward the centre of the capitellum whatever the positioning of the patient, since the radius articulates with the capitellum (figures A-D, even when not well positioned. Notice supracondylar fracture on B.

• In dislocation of the radius this line will not pass through the cemtre of the capitellum.

Normal Elbow Anatomy

• Anterior humeral line: a line drawn parallel to the anterior humerus should pass through the middle third of the capitulum.

• Proximal radial/Radiocapitellar line: a line along the longitudinal axis of the radius should pass through the center of the capitelum in all projections.

Lateral view of elbow with anatomical lines

Normal Elbow Anatomy

• Anterior Humeral line.A line drawn on a lateral view along the anterior surface of the humerus should pass through the middle third of the capitellum.

• In cases of a supracondylar fracture the Anterior Humeral line usually passes through the anterior third of the capitellum or in front of the capitellum due to posterior bending of the distal humeral fragment.

Fat Pad Sign and Joint effusion

• Normal lateral view of the elbow flexed in 90° - a fat pad is seen on the anterior aspect of the joint. This is normal fat located in the joint capsule. - on the posterior side no fat pad is seen since the posterior fat is located within the deep intercondylar fossa.

Fat Pad Sign and Joint effusion

Positive fat pad signDistention of the joint will cause the anterior fat pad to become elevated and the posterior fat pad to become visible.An elevated anterior lucency and/or a visible posterior lucency on a true lateral radiograph of an elbow flexed at 90° is described as a positive fat pad sign

FAT PAD SIGN

FAT PAD SIGN

FAT PAD SIGN

FAT PAD SIGN

MRI FAT PAD

THAT ALL FOR TODAY THANK YOU

Diagrams and notes taken from kursus for trauma radiography Nov 2006-sept 2007

BY DR ZALEHA BT ABD MANAF