Ch. 5 Elbow & Distal Humerus

Acute Flexion (Jones Method)

1. CR perpendicular to humerus, midway between epicondyles (distal humerus projection); 2. CR perpendicular to forearm (angling CR as needed), 2" superior to olecranon process (proximal forearm projection), SID 40", 64+-6, 64 6

What are the degrees of rotation for oblique projections?

45 degree lateral oblique external rotation.

Radial Head Laterals-Lateromedial

60+-6, 64 6, Flex 90 degrees, CR @ radial head, SID 40", 4 projections: palm up (ext rot), thumb up (true lat), palm down, thumb down (int rot)

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 the Coyle Method (Trauma axial laterals):

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

Trauma Axial Laterals-Axial Lateromedial (Coyle Method)

70+-6, 68 6 1. Radial head position: elbow flexed 90 degrees if possible, hand pronated, CR at a 45 degree angle toward shoulder @ radial head 2. 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.

A radiograph of an AP oblique elbow with medial rotation reveals that the radial head is superimposed over part of the coronoid process. What positioning error has been committed?

Excessive medial rotation

What bony landmarks are used for positioning the elbow?

Humeral epicondyles.

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.

Depression of the distal radius:

Ulnar notch: A small depression on the medial aspect of the distal radius.

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

When patient can't fully extend arm. 1 image with humerus parallel to IR, 1 image with forearm parallel to IR (Jones Method).

AP Elbow (elbow fully extended) evaluation

Hand supinated, arm fully extended, 60+-6, 64 6, CR @ mid elbow, SID 40"

What structures actually form the hinge joint?

Humerus, Ulna, & Radius. Olecranon process, olecranon fossa, coronoid process, coronoid fossa, ridge capitulum and trochlea, trochlear notch, trochlear sulcus

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).

AP Oblique-Medial (internal) rotation

Align arm & forearm with long axis of IR, pronate hand in a natural palm-down position, CR @ mid elbow joint, SID 40", 60+-6, 64 6; Coronoid process and trochlea

AP Oblique-Lateral (external) rotation

Align arm & forearm with long axis of portion of IR, center elbow joint to CR, supinate hand and rotate laterally 45 degree, CR @ mid elbow joint, SID 40", 60+-6, 64 6; Radial head and neck and capitulum

Lateral-Lateromedial

Align long axis of forearm with long axis of cassette, drop shoulder, rotate hand and wrist into true lateral position, thumb side up, CR @ mid elbow joint, SID 40", 60+-6, 64 6

Depressions of the distal humerus:

Anterior depressions: coronoid fossa & radial fossa Posterior depressions: Olecranon fossa

A young child comes to radiology with an elbow injury. The basic elbow projections demonstrate a possible non displaced fracture of the coronoid process. Beyond the medial oblique projection, what additional projections can be performed to demonstrate the coronoid process in profile?

Coyle method with 45 CR angle away from shoulder

A patient enters the ER with an elbow injury. The partially flexed AP and lateral positions reveal a possible fracture of the coronoid process. The patient elbow is partially flexed and he refuses to extend it further. Which one of the following positions should be performed to confirm the fracture of the coronoid process?

Coyle method with 80 flexion, CR angled 45 away from shoulder

A lateral elbow radiograph demonstrates about half of the radial head superimposed by the coronoid process of the ulna. Which of the following occurred?

No errors

AP Elbow (partially flexed) evaluation

Obtain two AP projections, one with forearm parallel to IR, the other one with the humerus parallel to IR, place support under wrist, CR @ mid elbow joint, SID 40", 64+-6, 64 6

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.

A radiograph of an AP projection of the elbow reveals that there is complete separation of the proximal radius and ulna. What positioning error has been committed?

excessive lateral rotation

A patient enters the ER in severe pain with a possible dislocation of the elbow. The patient has the elbow flexed more than 90. Which one of the following routines should be performed to confirm the diagnosis?

partially flexed AP and limited lateral projections