radiographic assessment as part of a biomechanical evaluation

radiographic assessment as part of a biomechanical evaluation

transverse-plane biomechanical analysis from dorsoplantar foot views (anteroposterior projections); sagittal-plane biomechanical analysis from lateral foot views Table 1
Table 1: Radiographic charting
AngleNormal rangeClinical features
Boehler's angle20-40°Angle between a line drawn from the superior-posterior aspect of the calcaneum and a line drawn from the anterior dorsal aspect of the calcaneum, on a lateral radiograph
Calcaneal inclination angleAngle between a line drawn to the undersurface of the calcaneum (on a lateral radiograph) and the support surface; the greater the calcaneal angle, the more supinated the rearfoot; the lower the angle, the more pronated the rearfoot
CYMA lineLazy S-shaped line that forms the midtarsal joint (talonavicular and calcaneocuboid joints) on a lateral radiograph; the smoothness of the CYMA line is lost in the excessively pronated or supinated foot
Hallux abductus angle0-20°Angle between the longitudinal bisection of the first metatarsal and the longitudinal bisection of the proximal phalanx of the hallux (on a dorsiplantar radiograph)
Hallux interphalangeal angle0-10°Angle between the longitudinal bisection of the proximal phalanx of the hallux and the longitudinal bisection of the distal phalanx of the hallux (on a dorsiplantar radiograph)
Lesser tarsal angle10°Angulation between the longitudinal bisection of the rearfoot and a longitudinal bisection of the lesser metatarsals (on a dorsiplantar radiograph). This angle is increased in a pronated foot, and decreased in a supinated foot
Metatarsus adductus angle10-20°Angle between the longitudinal axis of the second metatarsal and a line perpendicular to a line drawn from reference points on the medial cuneiform to the cuboid (on a dorsiplantar radiograph)
Metatarsus adductus primus angle8-10°Angulation between the bisections of the first and second metatarsal (on a dorsiplantar radiograph) >12° indicates pathology in a rectus foot; 10° indicates pathology in an adductus foot
Parallel pitch lines (PPLs)Lines drawn on a lateral radiograph of the foot: see Figure 1
PPL 1: a line drawn at the inferior margin of the calcaneum that joins the anterior tubercle and the medial tubercle of the posterior tuberosity of the calcaneum
PPL 2: a line drawn parallel to PPL 1 between the bursal projection (or posterior-superior prominence) at the superior margin of the calcaneum and the posterior lip of the talar articular facet
Divergent PPLs are characteristic of a foot with Haglund's deformity
Proximal articular set angle (PASA)0-8°Angle created between a line perpendicular to the longitudinal bisection of the first metatarsal and a line drawn to represent the effective articular cartilage of the head of the first metatarsal (on a dorsiplantar radiograph)
Superior calcaneal tuberosity angleAngle between the posterior tuberosity of posterior margin of the calcaneum and the anterior and medial tuberosities on the inferior margin of the calcaneum (on a lateral radiograph)
Talar declination angleAngle between the longitudinal bisection of the talus and the support surface (on a lateral radiograph); the nearer to the horizontal, the more supinated the rearfoot; the greater the declination of the talus, the more pronated the rearfoot (on a dorsiplantar radiograph)
Tibial sesamoid positionRelationship of the tibial sesamoid and the longitudinal bisection of the first metatarsal; the tibial sesamoid is normally medial to the first metatarsal bisection; christa erosion is likely where the tibial sesamoid abuts or crosses to the lateral part of the first metatarsal (on a dorsiplantar radiograph)
Total angle<75°Sum of the calcaneal inclination angle and superior calcaneal tuberosity angle see Figure 2

Biomechanical evaluation of plain radiographs is primarily made from dorsiplantar

Figure 1: Plantar fascia. MTP, metatarsophalangeal. This article was published in Neale's Disorders of the Foot, Lorimer, French, O'Donnell, Burrow, Wall. Copyright Elsevier, (2006).
Figure 2: Plantar fascia. MTP, metatarsophalangeal. This article was published in Neale's Disorders of the Foot, Lorimer, French, O'Donnell, Burrow, Wall. Copyright Elsevier, (2006).