Radiographic Positioning: Anatomical Axes, Landmarks & Positioning Aids – Lecture 3 Summary + Quiz

Introduction 

In radiology, proper patient positioning is critical for producing high-quality diagnostic images. Lecture 3 focuses on radiographic anatomical axes, oblique and decubitus positions, reference landmarks, and the use of positioning aids. These skills are vital for radiologic technologists, especially when capturing views for areas such as the spine, joints, and thorax.

This summary also includes a printable quiz to help students reinforce their learning and review key concepts in radiographic positioning techniques.

Key Radiographic Positions and Axes

• AP (Anteroposterior): X-ray beam passes from front to back (commonly used in trauma or portable imaging).

• PA (Posteroanterior): Beam passes from back to front (preferred for chest X-rays to reduce radiation to sensitive organs).

• Right & Left Lateral: Side-to-side projection, used for spine, chest, or limbs.

• Anterior & Posterior Oblique: Body angled diagonally; used for spine and ribs.

• Decubitus: Patient lies on their side to evaluate air/fluid levels.

• Trendelenburg: Head lower than feet, used in surgery.

• Erect: Standing position for spinal and extremity exams.

Landmarks in Radiographic Positioning

Radiographers use anatomical landmarks to align the body correctly:

• Sternal Angle – chest alignment

• Clavicles, Acromion, Glenoid Cavity – shoulder exams

• Iliac Crest, Greater Trochanter – hips and pelvis

• Knee Joint Line, Ankle Mortise – lower limb imaging

• Spinous Processes – spine X-rays

• Umbilicus, Sternum – abdomen and thorax reference

• Scaphoid Bone – wrist and hand exams

Positioning Aids in Radiography

To achieve accurate and safe imaging, these tools are used:

• Sandbags & Sponges – stabilize patient movement

• Lead Markers – indicate body side (L/R)

• Laser Lights & Grids – align anatomical planes

• Immobilization Devices – reduce motion artifacts

• Pillows, Cushions, Radiolucent Blocks – patient comfort and precise positioning

• Compression Plates & Scatter Shields – especially for mammography and radiation protection

Section A: Q&A (Short Answer – 10 Questions)

1. What does AP stand for in radiography?
   Answer: Anteroposterior

2. Why is PA preferred for chest X-rays?
   Answer: It reduces radiation to sensitive tissues like the breast.

3. Describe the decubitus position.
   Answer: Lying on one side to assess air/fluid levels.

4. What is the Trendelenburg position used for?
   Answer: Surgery, to access pelvic or abdominal organs.

5. Define oblique projection.
   Answer: Patient is angled to allow diagonal imaging of internal structures.

6. Name one landmark used in shoulder imaging.
   Answer: Acromion or Glenoid Cavity

7. What is the iliac crest used for?
   Answer: As a landmark in hip and lower back X-rays.

8. What are lead markers used for?
   Answer: To label anatomical sides (left or right).

9. Why are radiolucent blocks useful?
   Answer: They support the patient without blocking X-rays.

10. What is the purpose of scatter radiation shields?
    Answer: To protect the patient from excess radiation.

Section B: Circle the Correct Answer (Choose A, B, C, or D – 15 Questions)

1. AP projection passes from:
   A) Back to front
   B) Side to side
   C) Front to back
   D) Top to bottom
   Answer: C

2. PA projection is best for:
   A) Abdomen
   B) Chest
   C) Foot
   D) Skull
   Answer: B

3. Right Lateral position places:
   A) Right side near the receptor
   B) Back near the receptor
   C) Left side toward tube
   D) Head lower than feet
   Answer: A

4. Anterior Oblique places:
   A) Posterior side close
   B) Anterior side close
   C) Feet downward
   D) Side parallel
   Answer: B

5. Decubitus is used to detect:
   A) Fractures
   B) Air/fluid levels
   C) Tumors
   D) Brain injuries
   Answer: B

6. Trendelenburg is used in:
   A) Mammography
   B) Brain surgery
   C) Pelvic access
   D) Wrist exams
   Answer: C

7. The acromion is found in:
   A) Spine
   B) Hip
   C) Shoulder
   D) Wrist
   Answer: C

8. Iliac crest is part of the:
   A) Knee
   B) Arm
   C) Abdomen
   D) Pelvis
   Answer: D

9. Knee joint line is used to view:
   A) Pelvis
   B) Knee fractures
   C) Skull base
   D) Ankle injuries
   Answer: B

10. Radiolucent sponges are:
    A) Not visible on X-ray
    B) Made of lead
    C) Dangerous for imaging
    D) Used only in MRI
    Answer: A

11. Lead markers are used to:
    A) Support limbs
    B) Show body side
    C) Clean equipment
    D) Block scatter
    Answer: B

12. Spinous processes are landmarks for:
    A) Chest
    B) Legs
    C) Spine
    D) Arms
    Answer: C

13. Umbilicus is useful for:
    A) Chest alignment
    B) Spinal flexion
    C) Abdominal centering
    D) Hand movement
    Answer: C

14. Pillows and cushions are used for:
    A) Contrast injection
    B) Patient comfort
    C) Tumor detection
    D) CT scans only
    Answer: B

15. Compression plates are essential in:
    A) Spine CT
    B) Brain scans
    C) Mammography
    D) Hip exams
    Answer: C

Section C: True or False (10 Questions)

1. PA chest view exposes more radiation than AP. – False

2. Left lateral view places the patient’s left side closest to the receptor. – True

3. Oblique views are always used for the skull. – False

4. Decubitus views are ideal for checking air-fluid levels. – True

5. Trendelenburg is a standing position. – False

6. Lead markers show which side of the body is imaged. – True

7. Acromion is found in the hip. – False

8. Radiolucent blocks show clearly on the X-ray image. – False

9. Anatomical landmarks help ensure correct alignment. – True

10. Alignment lasers are used to aim the central ray. – True

Conclusion / Quick Notes

This lecture covers advanced concepts in radiographic positioning, including patient postures (AP, PA, lateral, oblique) and essential anatomical reference points like the clavicles, iliac crest, and malleoli. It also introduces vital positioning aids—tools that ensure accuracy, consistency, and minimized radiation exposure during imaging. Mastery of these elements is crucial for radiologic technologists to obtain precise and diagnostic-quality X-ray images.