Elbow Positioning : Jones Method

Wednesday, January 4, 2012

Jones Method : Acute Flexion

When fractures around the elbow are needed to study and patient is unable to extend arm the Jones orthopedic technique could make positioning simple. It is also known as the Jones Method. In this technique the patient's elbow should be in complete flexion, and lateral position make little difficult, but in the frontal projection must be made through the superimposed bones of the AP arm and PA forearm. Two exposure is required to visualize clearly the articulation of elbow joints. When distal humerus is the interest central ray should be perpendicular with the humerus likewise with the forearm, CR is should also be perpendicular to forearm if proximal radius and ulna is in interest, by slightly angling the central ray to achieve a perpendicular CR with the forearm.

Elbow Xray
Patient Position:
  • Seat patient at end of table, with acurately flexed arm resting on cassette.

Part Position:
  • Align and center humerus to long axis of IR, with forearm acutely flexed and fingertips resting on shoulder.
  • Adjust cassette to center elbow joint region to center of IR.
  • Palpate humeral epicondyles and ensure that they are equal distance from cassette for no rotation.

Pathology Demonstrated:
  • Fracture and moderate dislocations of the elbow in acute flexion are demonstrated.

Technical Factors:
Film Size : 8 x 10 inches
Divide in two, for 2 exposure
Lead Masking on Digital IR

  • IR size 18 x 24 cm (8 x 10 inches), lengthwise
  • Detail screen, tabletop (or divide in half, crosswise, for two projections)
  • Digital IR - used lead masking
  • 64 or add upto 6 kV range (increase 4 to 6 kV for proximal forearm)

  • Place lead shield over patient's lap to shield gonads.

Central Ray:
  • Distal Humerus: CR perpendicular to IR and humerus, directed to a point midway between epicondyles.
  • Proximal forearm: CR perpendicular to forearm (angling CR as needed), directed to a point approximately 2 inches (5 cm) proximal or superior to olecranon process.
  • Minimum SID of 40inches (100cm)

  • Collimate on four sides to area of interest.

ap acute flexion forearmRadiographic Criteria for Specific Projections:
  • Four sided collimation borders should be visible with CR and center of collimation field midway between epicondyles.

Proximal Humerus:
  • Forearm and humerus should be directly superimposed
  • Medial and lateral epicondyles and part of trochlea, capitulum, and olecranon process all should be seen in profile.
  • Optimal exposure should visualize distal humerus and olecranon process through superimposed structures.
  • Soft tissue detail is not readily visible on either projection.

Distal Forearm:
  • Proximal ulna and radius, including outline of radial head and neck, should be visible through superimposed distal humerus.
  • Optimal exposure visualizes outline of proximal ulna and radius superimposed over humerus.

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