Radiography With Richie

Lower Extremities

Clear, practical guidance for imaging the Hip, Knee, Femur, Tib‑Fib, Foot, and Ankle — written the way techs actually think when the department is busy and the patient is hurting.

If you want the “don’t overthink it — just do it this way” version of lower extremity positioning, you’re in the right place.

What This Section Is Designed to Do

Lower extremity imaging is all about balance literally. You’re dealing with weight‑bearing joints, long bones that love to rotate, and patients who often can’t move the way you need.

This section focuses on:

  • Keeping the patient safe and steady
  • Getting clean joint spaces on the first attempt
  • Using clear communication to reduce anxiety
  • Minimizing repeats through smart positioning choices

Everything here is built for real‑world clinical flow, not textbook perfection.

How to Use This Section

Each region is broken into its own set of positions, and every page includes:

  • Straightforward patient positioning
  • CR entry points
  • SID references
  • Common mistakes to avoid
  • Practical tips you’ll actually use

If you’re unsure where to start, the quick references in each accordion will get you through a shift without slowing down.

Pelvis
  • CR: Midway between ASIS and symphysis pubis (AP).
  • SID: 40 inches.
  • Collimation: Entire pelvic girdle (iliac crests to proximal femora).
  • Position: AP: Internally rotate feet 15°-20°.

Richie’s Tip: For trauma cases where you suspect pelvic ring fractures, the 40° Caudal (Inlet) and 40° Cephalad (Outlet) views are non-negotiable. They are the only way to see true displacement of the pelvic ring.

Hip & Femur
  • CR: Mid-femur (Femur); Femoral neck (Hip).
  • SID: 40 inches.
  • Collimation: Include proximal/distal joints.
  • Position: AP Hip/Femur: Rotate leg internally $15^{\circ}-20^{\circ}$.

Richie’s Tip: For the AP Hip, always internally rotate the feet. If you can see the lesser trochanter in profile, you haven’t rotated enough to show the femoral neck clearly.

Knee
  • CR: 1/2 inch distal to patellar apex.
  • SID: 40 inches.
  • Collimation: Distal femur and proximal tib-fib.
  • Position: Lateral: Flex knee $20^{\circ}-30^{\circ}$.

Richie’s Tip: On a Lateral Knee, use a $5^{\circ}-7^{\circ}$ cephalad angle to push the medial condyle up and out of the way, ensuring the joint space is perfectly open.

Tibia / Fibula
  • CR: Mid-shaft of tibia.
  • SID: 40-44 inches (for length).
  • Collimation: Must include both knee and ankle joints.
  • Position: AP: Dorsiflex foot $90^{\circ}$ to IR.

Richie’s Tip: If the leg is too long for the IR, turn the plate diagonally. It gives you those extra couple of inches needed to catch both joints on one shot.

Foot & Ankle
  • CR: 3rd MT base (Foot); Mid-malleoli (Ankle).
  • SID: 40 inches.
  • Collimation: Entire phalanges to tarsals/distal tib-fib.
  • Position: AP Foot: $10^{\circ}$ cephalad angle.

Richie’s Tip: For the Mortise Ankle, rotate the entire leg internally $15^{\circ}-20^{\circ}$ until the malleoli are parallel to the IR. This “clears” the joint space beautifully.