Lateral Forearm

Lateral Forearm X-ray

Lateral Forearm Position Diagram

Exposure Factors

Kilovoltage (kV)

Milliamperage (mAs)

Fine Focus

Focus Type

105 cm

Focus-Plate Distance

Without Bucky

Configuration

Low exposure: Optimized parameters for lateral forearm visualization

Visible Anatomical Structures

Should be clearly visible:

Ulna and radius in their entirety in lateral view
Carpal bones (proximal row) in profile
Elbow joint in lateral projection
Distal portion of humerus
Superposition of ulna and radius in their middle portion
Styloid processes ulnar and radial
Distal radioulnar joint

Superposition Feature in Lateral View

In true lateral projection of the forearm, ulna and radius superpose in their middle portion due to their parallel anatomical arrangement.

This is normal and expected in a correctly positioned lateral view.

Plate Size and Division

30 × 35 cm

Total size

Large plate for complete forearm

2 portions

Longitudinal division

Second portion for lateral projection

Plate divided longitudinally: The second portion of the plate is used to complete the study with lateral view

Patient Positioning

Place entire upper extremity in the same horizontal plane as the plate

Align longitudinal axis of forearm with longitudinal axis of selected portion of the cassette

Position hand in lateral position (thumb up)

Medial (ulnar) part of forearm in direct contact with cassette

Flex elbow approximately 90° for comfort

Keep shoulder in relaxed position

Center forearm in corresponding portion of cassette

Include elbow joint and wrist in the field

Critical Positioning Point

Medial part in contact with cassette

To obtain a true lateral projection of the forearm, the medial (ulnar) surface of the forearm must be in direct contact with the cassette.

This ensures forearm bones are in the correct plane for lateral visualization.

Central Ray Point

Midpoint of forearm

Direction: Vertical and perpendicular to midpoint of forearm

Location: Half distance between elbow and wrist

Objective: Middle portion where ulna and radius superpose

Specific Hand and Forearm Position

Hand Position

Hand in lateral position

Thumb upward

Neutral forearm pronation

Contact with Cassette

Medial surface in contact

Ulna directly supported

Radius lateral to ulna

Patient Instructions

"Do not move during exposure"

Maintain position without movement during radiographic exposure

Special attention to keep medial part of forearm in contact with cassette

Optimal Image Characteristics

True lateral view

Middle superposition of ulna and radius

Correct superposition

Ulna anterior to radius in distal portion

Visible joints

Elbow and wrist in profile

Complete field

From distal humerus to carpus

Common Technical Challenges

Frequent problems in lateral forearm projection:

Forearm rotation causing oblique view
Poor hand position (not lateral with thumb up)
Incorrect contact with cassette (not medial surface)
Incorrect superposition of ulna and radius
Exclusion of joints due to poor centering
Poor alignment of longitudinal axis
Patient movement during exposure

Solution: Ensure medial surface of forearm is in direct contact with cassette and hand in lateral position with thumb upward

Complete Radiological Evaluation

AP Projection

First portion of plate

• General evaluation and alignment

• Separate visualization of ulna and radius

Lateral Projection

Second portion of plate

• Displacement evaluation

• Normal bone superposition

• Profile visualization

Both projections are necessary for complete evaluation of fractures, displacements and forearm alignment

Specific Clinical Indications

Displacement fracture evaluation

Angular deformities

Foreign bodies or projectiles

Complex trauma