Ch. 5 Elbow & Distal Humerus

How much rotation of the humeral epicondyles is required for the AP medial oblique projection of the elbow:

45 degrees.

What are the degrees of rotation for oblique projections?

45 degrees. Pg. 164

Positioning for geriatric patients:

Ensure that adequate immobilization is used to prevent movement during the exposure. pg. 134

Humeral epicondyles should be this way to the IR for a lateral projection of the elbow:

Perpendicular.

These are not required unless the anatomy measures greater than 10 cm:

Grids.

General positioning rule for upper limbs:

Always place the long axis of the part being imaged parallel to the long axis of that portion of the IR being exposed; all body parts should be oriented in the same direction. pg. 135

Fat pads of the elbow:

(1) Anterior fat pad (anterior to the distal humerus), (2) Posterior fat pad (deep within the olecranon process), & (3) Supinator fat pad/stripe (anterior to the proximal radius). Pg. 133

What bony landmarks are used for positioning the elbow?

Humeral epicondyles. Pg. 162

What structures actually form the hinge joint?

Humerus, Ulna, & Radius.

A nonvisible posterior fat pad suggests a _________ study:

Negative.

The lateral elbow projection best demonstrates:

The trochlear notch.

Technical factors for AP forearm:

62 kV 6 mAs

Technical factors for all elbow projections (exceptions for Coyle and Jones Method):

64 kV 6 mAs

Technical factors for the Jones Method (AP projections of elbow):

64 kV 6 mAs (increase 4 to 6 kV for proximal forearm).

Technical factors for Lateral-lateromedial forearm:

66 kV 6 mAs

Technical factors for the Coyle Method (Trauma axial laterals):

68 kV 6 mAs (increase factors by 4 to 6 kV from lateral elbow because of angled CR).

Structure that is the most lateral:

Capitulum.

Important guideline followed that allows the computer to provide accurate information regarding the exposure index:

Close collimation.

Best demonstrates radial head for a trauma patient with elbow flexed 90 degrees & CR angled 45 degrees toward shoulder:

Coyle Method.

AP Elbow (elbow fully extended) evaluation criteria/structures shown:

Extend elbow, supinate hand, & align forearm with long axis of portion of IR; center elbow joint to center of IR; have patient lean laterally for true AP projection; CR directed to mid elbow joint (3/4" distal to midpoint between epicondyles), SID 40"; structures shown: distal humerus, elbow joint space, & proximal radius and ulna are visible.

Jones Method (AP projections of elbow in acute flexion):

Fractures and moderate dislocations of the elbow in acute flexion. Total of two projections.

Proper name for the acute flexion elbow projection:

Jones Method.

The lateral elbow projection best demonstrates the _______ _______ in profile:

Olecranon Process.

Structure that is the most proximal & posterior:

Olecranon process.

Place the long axis of the part ______ to the long axis of the image receptor:

Parallel.

Trauma Axial Laterals-Axial Lateromedial (Coyle Method) criteria/structures shown:

Radial head position: elbow flexed 90 degrees if possible, hand pronated, CR at a 45 degree angle toward shoulder, centered to radial head (mid elbow joint); Coronoid process position: elbow flexed only 80 degrees from extended position, hand pronated, CR angled 45 degrees from shoulder, into mid elbow joint; SID 40"; structures shown: radial head or coronoid process.

Positioning for trauma patients:

Trauma patients can be radiographed on the table or taken directly on the stretcher; the patient should be moved to one side on the stretcher to provide space for the cassette. pg. 134

Depressions of proximal ulna:

Trochlear notch: large concave depression that articulates with the distal humerus. Radial notch: the small, shallow depression located on the lateral aspect of the proximal ulna. Pg. 128-129

The depressed center of the trochlear used for evaluating on a lateral elbow:

Trochlear sulcus.

Depression of the distal radius:

Ulnar notch: A small depression on the medial aspect of the distal radius. Pg. 128-129

What is used for evaluating rotation on a lateral elbow?

When the elbow is flexed at 90 degrees, is the appearance of three concentric arcs, (1) the trochlear sulcus, (2) the outer ridges of the capitulum & trochlea, and the (3) trochlear notch of the ulna. Also, the olecranon process is in profile. Pg. 129

Acute Flexion (Jones Method) criteria/structures shown:

Align and center humerus to long axis of IR, forearm acutely flexed and fingertips resting on shoulder, center elbow joint to center of IR, make sure epicondyles are equal distances to IR, CR perpendicular to humerus, midway between epicondyles (distal humerus projection); CR perpendicular to forearm (angling CR as needed), 2" superior to olecranon process (proximal forearm projection), SID 40"; structures shown: proximal humerus & distal forearm.

AP Oblique-Medial (internal) rotation criteria/structures shown:

Align arm & forearm with long axis of IR, center elbow to CR, pronate hand in a natural palm-down position, rotate arm 45 degrees, CR directed to mid elbow joint (3/4" distal to epicondyles), SID 40"; structures shown: oblique projection of the distal humerus, proximal radius, & ulna, radial head, neck, & tuberosity.

AP Oblique-Lateral (external) rotation criteria/structures shown:

Align arm & forearm with long axis of portion of IR, center elbow joint to CR, supinate hand and rotate laterally the entire arm, palpate epicondyles to determine 45 degree rotation of distal humerus, CR directed to mid elbow joint (3/4" distal to midpoint of epicondyles), SID 40"; structures shown: Oblique projection of the distal humerus and proximal radius and ulna is visible, radial head, neck, & tuberosity.

Lateral-Lateromedial criteria/structures shown:

Align long axis of forearm with long axis of cassette, center elbow joint to CR and IR, drop shoulder, rotate hand and wrist into true lateral position, thumb side up, place support under hand and wrist, CR directed to mid elbow joint (1.5" medial), SID 40"; structures shown: lateral projection of the distal humerus and proximal forearm, the olecranon process, fat pads of the elbow joint.

Depressions of the distal humerus:

Anterior depressions: coronoid fossa & radial fossa Posterior depressions: Olecranon fossa Pg. 128-129

Lateral-Lateromedial Forearm:

Elbow flexed 90 degrees, align & center forearm, include both wrist & elbow joints, rotate hand & wrist into true lateral position, ensure distal radius & ulna are superimposed, CR perpendicular to IR, directed to midforearm, ensure 1 to 1.5" distal to wrist & elbow joints, SID 40"; structures shown: lateral radius & ulna, proximal row of carpals, elbow, & distal end of the humerus, fat pads & stripes of the wrist & elbow joints.

Trochlea & olecranon process primarily form this joint:

Elbow joint.

AP Forearm:

Hand & arm fully extended and palm up (supinated); align & center forearm, include wrist & elbow joints, instruct patient to lean laterally; CR perpendicular to IR, directed to midforearm, allow 1 to 1.5" distal to wrist and elbow joints, SID 40", structures shown: radius & ulna, proximal row carpals & distal humerus, fat pads & stripes of wrist & elbow joints.

General Positioning Considerations:

Have the patient seated sideways at the end of the table in a position that is neither strained nor uncomfortable; patient's body should be moved away from the xray beam; the height of the table top should be near shoulder height; the bucky tray should be moved to the opposite side of the radiographic table. pg. 134

The two bony landmarks palpated for positioning of the elbow:

Humeral Epicondyles.

Positioning for pediatric patients:

Immobilization such as sponges & tape; sandbags depending on their weight and the patient; the parent can hold the child while wearing proper shielding. pg. 134

Routine AP oblique projection of the elbow best demonstrates the radial head & tuberosity free of superimposition:

Lateral rotation.

Projection of the elbow best demonstrates the olecranon process in profile:

Lateral.

Projection of the elbow that best demonstrates an elevated or visible posterior fat pad:

Lateromedial.

Radiograph of the elbow demonstrates the radius directly superimposed over the ulna and the coronoid process in profile:

Medial Internal Oblique.

AP Elbow (partially flexed) evaluation criteria/structures shown:

Obtain two AP projections, one with forearm parallel to IR, the other one with the humerus parallel to IR, place support under wrist, CR directed to mid elbow joint (3/4" distal to midpoint between epicondyles), SID 40"; structures shown: distal humerus (humeral projection), proximal radius & ulna (forearm projection).

Coyle Method (Trauma axial laterals-lateromedial):

Pathologic processes or trauma to the area of the radial head and/or the coronoid process of ulna; effective projections when the patient cannot extend elbow fully or medial or lateral obliques of the elbow.

Radial Head Laterals-Lateromedial criteria/structures shown:

Patient arm flexed at 90 degrees on cassette with humerus, forearm, & hand on same horizontal plane, center radial head area on IR, center radial head region to CR, take four projections: external rotation-hand supinated, hand lateral, hand pronated, & hand with internal rotation; CR directed to radial head (1" distal to lateral epicondyle); SID 40"; structures shown: radial tuberosity.

The two small depressions found on the anterior aspect of the distal humerus:

Radial & coronoid fossa.

In radial head projection, what is the only difference in positioning?

The hand.

Why would an elbow be imaged in a partially flexed position and how?

When the patient cannot partially extend the elbow and elbow remains flexed near 90 degrees, take two projections, one with the humerus parallel to IR, and the other one with the forearm parallel to the IR, but angle the CR 10 to 15 degrees into the elbow joint, or if flexed more than 90 degrees, use the acute flexion projection (Jones Method). Pg. 163