ESSR 2018 / P-0066
A step-by-step imaging tour of congenital abnormalities of the foot
Congress: ESSR 2018
Poster No.: P-0066
Type: Educational Poster
Keywords: Congenital, Normal variants, Plain radiographic studies, MR, CT, Musculoskeletal system
Authors: B. Sharif, M. Khoo; Stanmore/UK
DOI:10.1594/essr2018/P-0066

Background

ANATOMY OF THE FOOT

 

 

The anatomy of the foot is complex. The foot can be broadly divided into three main parts: 

 

Hindfoot

  • The most posterior portion of the foot, comprised of the talus and calcaneus. 
  • This includes the ankle joint (tibiotalar) and subtalar joint (which has three facets: anterior, middle and posterior)
  • The hindfoot is joined to the midfoot via the Chopart joint (mid tarsal joint)

 

Midfoot

 

  • This lies between the hindfoot and forefoot and contains the navicular, cuboid and cuneiforms. 
  • It is joined to the forefoot via the tarsometatarsal joints.

 

Forefoot

 

  • This includes the metatarsals and phalanges
Fig. 1: Right foot radiographs demonstrating the broad anatomical divisions of the foot into the hindfoot, midfoot and forefoot.
References: - Stanmore/UK

 

 

RADIOLOGIC EVALUATION OF THE ALIGNMENT OF THE FOOT

 

Requires AP and lateral weight bearing radiographs.

 

AP radiograph:

 

  • This allows assessment of the alignment of the hindfoot. The normal talocalcaneal angle or kite angle is 30-45 degrees.
  • In order to work out the talocalcaneal angle, a line should be drawn down the axis of the talus (mid-talar line), which should intersect the first metatarsal. A further line should be drawn down the axis of the calcaneus (mid calcaneal line), this should intersect the fourth metatarsal. A lateral radiograph may also be used to work out the talocalcaneal angle.  Fig. 5
Fig. 2: Weight bearing AP radiograph of the left foot demonstrating normal hindfoot alignment. The mid-talar line intersects the first metatarsal and the mid-calcaneal line intersects the fourth metatarsal. The talocalcaneal angle is normal.
References: - Stanmore/UK
  • In hindfoot varus, the calcaneus is adducted and rotated under the talus, resulting in a reduced talocalcaneal angle.

 

Fig. 3: Weight bearing AP radiograph of the right foot demonstrating a reduced talocalcaneal angle, in keeping with varus deformity of the hindfoot. The mid-talar and mid-calcaneal lines are not intersecting the first metatarsal or fourth metatarsal respectively.
References: - Stanmore/UK
  • In hindfoot valgus, the calcaneus is abducted, the talus loses its support, resulting in a more vertically orientated talus. The mid-talar line no longer intersects the first metatarsal, leading to a widened talocalcaneal angle.
Fig. 4: Weight bearing radiograph of the right foot. There is hindfoot valgus, the mid-talar line and mid-calcaneal lines no longer intersect the first and fourth metatarsals respectively. The talocalcaneal angle is subsequently widened. Of note, this is a patient with congenital vertical talus.
References: - Stanmore/UK

 

 

Lateral radiograph:

 

  • Draw a line down the axis of the distal tibia and a further line at the base of the calcaneus. The angle between the two is the tibiocalcaneal angle. This should be 70-90 degrees.

 

Fig. 6: Lateral radiograph of the right ankle demonstrating how to measure the talocalcaneal angle.
References: - Stanmore/UK
  • In equinus, there is fixed calcaneal plantarflexion, resulting in a widened tibiocalcaneal angle (>90 degrees).
Fig. 7: Lateral radiograph of the right foot demonstrating an increased tibiocalcaneal angle (>90 degrees) due to the foot being held in fixed equinus.
References: - Stanmore/UK
  • Conversely, fixed calcaneal dorsiflexion results in a reduced tibiocalcaneal angle (<60 degrees).
POSTER ACTIONS Add bookmark Contact presenter Send to a friend Download pdf
SHARE THIS POSTER
2 clicks for more privacy: On the first click the button will be activated and you can then share the poster with a second click.

This website uses cookies. Learn more