Hip Radiography: Antero-Posterior View

Hip Region - Radiographic Appearance (Antero-Posterior View)

• The patient should be placed flat on their back, with the toe of the foot pointing somewhat towards the median plane to avoid foreshortening the neck of the femur.
• Hip joint space appears as a radiolucent interval between the white lines of the rim of the acetabulum and the head of the femur.
• The extent to which the lesser trochanter is visible indicates limb position during exposure; it appears more prominent when the femur is laterally rotated and less so when medially rotated.
• The neck of the femur normally forms a 25°-30° angle with the coronal plane, projecting medially and forwards.
• The superior and medial edge of the acetabulum appears as a curved white line of cortical bone, with the posterior rim partly superimposed on the head of the femur.
• The greater trochanter lies in a plane somewhat posterior to the head of the femur, and its shadow overlaps the head in external rotation.
• The cortex of the head of the femur casts a white line, with the fovea capitis femoris visible as a small depression.

Knee - Lateral View

• The knee is partially flexed with its lateral aspect placed next to the film.
• The intercondylar eminence of the tibia slightly overlaps the femoral condyles.
• The spine lies somewhat behind the midpoint of the superior surface of the tibial condyles.
• The knee joint space is obscured by overlapping bone shadows.

Knee - AP View

• The anterior and posterior margins of the medial and lateral femoral condyles are not superimposed due to diameter differences.
• The patella is seen in front of the condyles of the femur.
• The intercondylar eminence of the tibia presents a spinous appearance on the middle of the upper surface of the tibia.
• The intercondylar notch of the femur is variable and superimposed by the patella.
• Typically, there is a 0.5 cm gap in the knee joint space due to the radiolucency of the articular cartilages.
• The patella is superimposed on the lower end of the femur, appearing as a circular translucent shadow with its lower edge about 1.25 cm above the knee joint space.

Knee - AP Radiographic appearance

• Articular ends of the femur and tibia are demarcated by thin white lines of cortical bone in a full extension antero-posterior view.
• The head and styloid process of the fibula are seen considerably below the knee joint space on the lateral side and are superimposed by the tibia.

Foot - Radiographic Appearance

• With the sole on the film, the outlines of tarsal and metatarsal bones and phalanges are clearly seen.
• The anterior part of the calcaneum articulates directly with the cuboid bone on its proximal surface.
• The medial, intermediate, and lateral cuneiform bones articulate with the navicular proximally.
• Intertarsal joint spaces are clearly visible.
• The lateral cuneiform presents an obscure outline due to overlapping with the intermediate cuneiform and cuboid bones.

Ankle - AP View - Radiographic Appearance

• The lower end of the fibula is superimposed on the tibia, obscuring the joint space between them and the talus.
• The lower end of the tibia is separated from the upper surface of the talus by the ankle joint space, which continues on the medial side and separates the talus from the medial malleolus.
• The talus casts a four-sided shadow below the lower ends of the tibia and fibula.
• The first (m1), second (m2), and third (m3) metatarsals tend to be partly superimposed, whereas the fourth (m4) is clearly demarcated, and the fifth (m5) has a tubercle on its base.
• The navicular is easily identified anterior to the head of the talus.
• The talus is mounted on the calcaneum and overridden by the lower end of the tibia.
• The lower end of the tibia is easily made out, and the talo-tibial joint space is clearly visible, with the medial malleolus overlapping the talus.

Ankle and Foot - Lateral View

• The lateral malleolus rests on the film in this position.
• The calcaneum projects backwards, with pressure lamellae presenting a characteristic pattern.
• The cuboid shows its prominent projecting ridge on the plantar outline.
• The three cuneiform bones are superimposed, and their position is determined by identifying the cuneiform-metatarsal joint spaces.
• The lower end of the fibula is partly superimposed on the tibia and talus, with the shadow of the lateral malleolus lower than that of the medial malleolus.

Supernumerary Bones

• Three common supernumerary bones exist:
  • Os tibiale: Lies close to the tuberosity of the navicular.
  • Os trigonum: Lies at the posterior end of the talus.
  • Os peroneum: A sesamoid bone in the tendon of the peroneus longus, close to the cuboid.