AP of Foot - Anteroposterior Projection

AP Foot Projection - Anatomical View

AP Foot Positioning - Technical View

Supine

Seated

Exposure Factors

Kilovoltage (kV)

4-10

Milliamperage (mAs)

Fine Focus

Focus Type

105-115 cm

Focus-Plate Distance

Equipment: Without bucky. Position: Supine or seated.

Note: Low mAs due to low bone density of the foot

Plate Size

24 × 30 cm

Longitudinally divided in half

CENTERING POINT

Base of the Third Metatarsal

Central anatomical point of the foot for precise centering

Anatomical Regions of the Foot

Forefoot

Phalanges and metatarsals

Midfoot

Cuneiforms, cuboid and navicular bones

Hindfoot

Talus and calcaneus

Visible Anatomical Structures

Phalanges

Distal, middle and proximal

Metatarsals

1st to 5th metatarsal

Tarsal Bones

Cuneiforms, navicular, cuboid

Talus and Calcaneus

Hindfoot bones

Interphalangeal joints - Distal and proximal
Metatarsophalangeal joints - Base of the toes
Medial and lateral malleolus - Distal portion of tibia and fibula
Cuneiforms - First, second and third
Navicular bone - Tarsal scaphoid
Talonavicular joint - Between talus and navicular
Cuboid - Lateral tarsal bone
Talar head - Anterior portion of talus
Fifth metatarsal process - Peroneal tuberosity
Calcaneocuboid joint - Between calcaneus and cuboid
Calcaneus - Heel bone
Distal part of tibia and fibula - Including malleoli
Joint spaces - All foot joints

10° CEPHALIC ANGULATION

The central ray should be angulated cephalically about 10° directed to the base of the third metatarsal.

This angulation allows:

Better visualization of joint spaces
Reduction of bone overlap
Optimal visualization of all foot bones

Patient Positioning

Patient in supine or seated position

Knee of affected limb flexed

Sole of the foot with toes fully supported on the cassette

Longitudinal axis of the cassette aligned with longitudinal axis of the foot

Foot in complete contact with cassette surface

Avoid rotation of the foot or ankle

Keep toes extended and naturally separated

Cassette centered at base of third metatarsal

Include entire foot from heel to toe tips

Ensure stability of position during exposure

Central Ray Direction

Directed to base of third metatarsal with 10° cephalic angulation

↗ 10°

10° CEPHALIC

Anatomical point: Base of third metatarsal

Angulation: 10° cephalic (towards head)

Entry point: Dorsal foot, approximately at mid-midfoot

Exit point: Plantar, at level of longitudinal arch

Goal: Complete visualization of all foot bones and joints

10° cephalic angulation - Essential for this projection

Patient Instructions

"Do not move during the examination"

Keep foot completely still - Toes supported on plate without moving

Technical Considerations

10° Angulation

Cephalic angulation essential for optimal joint visualization.

Axis Alignment

Precise alignment between cassette axis and longitudinal foot axis.

Complete Contact

Sole of foot with toes fully supported on cassette.

Clinical Indications

Metatarsal fractures

Foot osteoarthritis

Sports injuries

Deformities

Foot trauma

Image Quality Criteria

Complete Visualization

All foot bones from toes to heel visible

Joint Spaces

Joint spaces open and without overlap

Correct Alignment

Foot axis aligned with cassette axis

Radiological Study of the Foot

COMPLEMENTARY PROJECTIONS

AP foot projection is typically complemented with:

AP Foot

Dorsoplantar view

Lateral Foot

Mediolateral view

Oblique Foot

45° view

These three projections allow three-dimensional evaluation of the foot

Special Technical Note

LOW MILLIAMPERAGE (4-10 mAs)

The foot requires very low mAs (4-10 mAs) due to:

Low bone density - Small and thin bones
Little soft tissue - Minimal X-ray attenuation
High sensitivity - Images easily overexposed
Fine detail required - Visualization of small structures

Adjust mAs according to foot size and patient age (children require even less)

AP FOOT PROJECTION