Radiographic Angles

Front 1

Longitudinal Axis of the Rearfoot

Back 1

Line is made connecting the center of the posterior surface of the calcaneus and at the anterior medial edge of the calcaneus

If obscure, may use lateral border of the calcaneus as reference (5° abducted)

Front 2

Longitudinal Axis of the Talar Neck and Head

Back 2

Draw line across widest dimension of the head of the talus, as well as the neck. Mark the midpoints, then connect the two

Front 3

Longitudinal Axis of the Lesser Tarsus

Back 3

First, mark anterolateral aspect of the calcaneus, as well as the lateral proximal corner of the base of the 4th metatarsal. Find the midpoint of these two dots. Second, mark the anteromedial aspect of the talus at its articulation with the navicular, as well as the proximal medial corner of the base of the 1st metatarsal. Find the midpoint of these two dots. Finally, connect the two midpoint marks, draw a line perpendicular to it, which is your longitudinal axis of the lesser tarsus

Should be approximately parallel to the longitudinal bisection of the 2nd cuneiform

Front 4

Longitudinal Axis of the Metatarsus/Forefoot

Back 4

It is the longitudinal axis of the 2nd metatarsal

Front 5

Longitudinal Axis of the Digits

Back 5

It is the longitudinal bisection of the proximal phalanx of the 2nd toe

Should be approximately parallel to the longitudinal axis of the rearfoot

Front 6

Talocalcaneal Angle

Back 6

Angle made by the longitudinal axis of the rearfoot and the longitudinal axis of the talar neck and head

Normal: 15-18° (Increases 5° if lateral border of calcaneus is used)

Front 7

Lesser Tarsus Angle

Back 7

Angle between the longitudinal bisection of the rearfoot and the longitudinal bisection of the lesser tarsus

Normal: 10° ± 5

Front 8

Metatarsus Adductus Angle

Back 8

Angle between the longitudinal axis of the lesser tarsus and the longitudinal axis of the metatarsus

Normal: metatarsal axis adducted 10-20° from lesser tarsus angle

Front 9

Engel’s Angle

Back 9

Angle formed by longitudinal axis of the metatarsus and the longitudinal axis of the 2nd cuneiform

Normal: 13-23°

Front 10

Z Foot Concept

Back 10

Assesses foot linearity through 3 reference lines:
- 1st: longitudinal axis of the rearfoot
- 2nd: longitudinal axis of the lesser tarsus
- 3rd: longitudinal axis of the metatarsus

The more parallel the reference lines, the more stable. Instability/less compression results as joints become non-perpendicular to compression force

Front 11

Forefoot Angle

Back 11

Angle formed by the longitudinal axis of the rearfoot and the longitudinal axis of the forefoot

Normal: 8-12° adducted

Front 12

Proximal Articular Set Angle (PASA)

Back 12

Angle formed between a line perpendicular to the 1st metatarsal articular cartilage and the longitudinal axis of the first metatarsal

Normal: 0-8° abducted

Front 13

Distal Articular Set Angle (DASA)

Back 13

Angle formed between a perpendicular of the proximal articular surface and the longitudinal bisection of the proximal phalanx of the hallux

Normal: 7-9° abducted

Front 14

Hallux Abductus Angle

Back 14

Angle formed between the longitudinal bisection of the proximal phalanx of the hallux and the 1st metatarsal

Normal: 15° or less

Front 15

Metatarsus Primus Adductus Angle

Back 15

Angle formed between the longitudinal bisections of the 1st and 2nd metatarsals

Normal: 8° adducted

Front 16

“Atavastic Cuneiform”

Back 16

Refers to the space between the 1st and 2nd cuneiforms seen in some feet

“Atavastic” was used to describe the split between the cuneiforms as remnants of a thumb-like appendage

Atavastic cuneiform is a sign of an overpronated foot, with subsequent hypermobility of the 1st ray in gait

Front 17

Sesamoid Position

Back 17

Normal: Position 1, where medial sesamoid is medial to the 1st metatarsal bisection

Front 18

First Metatarsal Length

Back 18

Normal: ±2mm

Front 19

Hallux Interphalangeal Angle

Back 19

Angle formed between the longitudinal bisections of the hallux proximal and distal phalanges

Normal: 13°

Front 20

5th Intermetatarsal Angle

Back 20

Angle formed between the medial birder of the proximal portion of the 5th metatarsal and the longitudinal bisection of the 4th metatarsal

Normal: 6.5°

Front 21

Lateral Deviation Angle

Back 21

Angle formed between the longitudinal bisection of the 5th metatarsal head and neck, and the line drawn parallel to the proximal medial border of the 5th metatarsal

Distinguishes 5th met splaying away from 4th met from distal lateral curving of the 5th met head itself

Normal: 2-3°

Front 22

Talonavicular Articulation

Back 22

Normal: 75-80% of the articular surface of the head of the talus articulates with the navicular and is roughly rectangular in shape

Front 23

Calcaneocuboid Angle

Back 23

Angle formed between a tangent drawn along the lateral side of the cuboid and a tangent along the lateral border of the calcaneus

Normal: 0-5°

Front 24

Talocuboid Angle

Back 24

Angle is equal to the sum of the talocalcaneal angle and the calcaneocuboid angle

It is the angle formed between the longitudinal bisection of the talar head and neck, and a tangent along the lateral side of the cuboid

Normal: 15-20°

Front 25

Metatarsal Base Superimposition

Back 25

Normal: metatarsal bases are superimposed by 50%

Front 26

Calcaneal Inclination Angle

Back 26

Mark the anterior, plantar extent of the calcaneal tuberosity, as well as at the most plantar point of the calcaneocuboid articulation. Draw a line through the points, and find the angle between that line and the supporting surface (or line between calcaneal tuberosity and 5th metatarsal head).

Normal: 18-20°

Front 27

Fowler and Phillip Angle

Back 27

Angle formed between line connecting anterior tubercle and medial process of plantar tubercle and line connecting posterosuperior prominence and posterior tuberosity

>75° is pathologic

Front 28

Parallel Pitch Lines

Back 28

A line parallel to the calcaneal inclination line is drawn from the posterior lip of the posterior facet in a posterior direction

If the posterosuperior portion of the calcaneus extends superior to the dorsal line, it should be considered large

Front 29

Boehler’s Angle

Back 29

Angle formed between the anterior dorsal and posterior dorsal aspects of the calcaneus

Normal: 20-45° (0-6° difference between limbs)

Front 30

Talar Declination Angle

Back 30

Mark the superior articular point of the head of the talus with the navicular, as well as the anterior inferior superimposition of the articular surface of the talus by the calcaneus. Connect the marks, and draw the perpendicular. That is the talar declination line

Normal: 21°

Front 31

Dorsiflexed Talus: Pseudoequinus

Back 31

Talus and calcaneus may be dorsiflexed via a retrograde force from a plantarflexed forefoot

Pseudoequinus may be present whenever the talar declination line passes dorsal to the 1st metatarsal

Front 32

Talar Trochlear Surface Shape

Back 32

Normal: round surface profile

Severe equinus deformity: trochlear surface appears flattened, caused by the forceful pulling downward of the leg by the triceps surae, as well as overall body weight

Front 33

Tibiotrochlear Angle

Back 33

Angle formed between the longitudinal axis of the tibia and the transtrochlear axis

Normal: 10° of DF when relaxed and stress lateral views are taken

Front 34

Lateral Talocalcaneal Angle

Back 34

Angle formed between the calcaneal inclination line and the talar declination line

Normal: 35-40°

Front 35

Sustentaculum Tali Changes

Back 35

Normal: parallel to supporting surface

With prolonged pronation, it may begin to slope plantarly, making it easier for the talus to adduct and slide anteriorly, perpetuating closed kinetic-chain subtalar joint pronation

Front 36

Signs of Restricted STJ Motion

Back 36

Defined as under 15° of frontal and transverse plane motion

Signs
- Narrowing of the posterior facet joint space
- Broadening of the lateral talar process secondary to calcaneal eversion
- Sclerotic circle around the sustentaculum tali, “halo sign”
- Talar beaking, or hypertrophy of the superior lateral aspect of the talar head

Front 37

Cyma Lines

Back 37

A lazy S-shaped line that runs through the joint spaces of well-aligned calcaneocuboid and talonavicular joints

Pronation: causes anterior break in line, as talus appears to move anteriorly

Supination: causes posterior break, as talus appears to move posteriorly

Front 38

Foot Arch Formula

Back 38

Demp formula


Foot length = distance between calcaneal tuberosity and 1st-metatarsal head

Normal: high point of the arch (base of the navicular) should be 40% of length

Front 39

Naviculocuboid Superimposition

Back 39

Normal: navicular is superimposed on 50% of the cuboid

Increases with midtarsal pronation

Decreases with midtarsal supination

Front 40

First Metatarsophalangeal Joint

Back 40

Normal: longitudinal bisections of the 1st metatarsal and proximal phalanx should intersect in the middle of the 1st metatarsal head

Front 41

Mallet Toe

Back 41

Plantarflexion deformity of the distal IPJ

Frequently occur after shortening or amputation of an adjacent ray

Pain or ulceration at the distal end of the toe

Front 42

Claw Toe

Back 42

Flexion contractures at the IPJ of the digit, MC with extension of the MTPJ

Frequently associated with pes cavus and extensor substitution as the extensors attempt to DF the foot against equinus, either forefoot (pseudoequinus), or ankle

Front 43

Hammertoe

Back 43

Proximal IPJ flexion contracture and either distal IPJ hyperextension/flexion deformity

Flexor stabilization is usually the etiology as the overactive flexors attempt to reduce pronation of the foot

Can also come from flexor substitution, as the deep posterior muscles assist weak triceps surae with ankle plantarflexion