Radiographic measurements of the talus and calcaneus in the adult pes planus foot type.

OBJECTIVE: A distinctive feature of the modern human foot is the presence of a medial longitudinal arch when weight-bearing. Although the talus and calcaneus play a major role in the structure and function of the human foot, the association between the morphology of these bones and longitudinal arch height has not been fully investigated. A better understanding of this relationship may assist in the interpretation of pedal remains of fossil hominins, where features of the foot and ankle morphology have been described as providing evidence for the presence of a longitudinal arch. METHODS: For this study, weight-bearing radiographs of 103 patients from an urban US Level 1 trauma center, taken as part of a clinical examination for medical evaluation, were selected. These radiographs were classified as to foot type by arch height as defined using the calcaneal inclination angle. From this group, 68 radiographs were suitable for linear and angular measurements of the talus and 74 of the calcaneus. The relationships between these measurements and arch height were explored using least squared linear regression analysis. RESULTS: The results demonstrate that angular measurements of the calcaneus (particularly those that reflect the relationship of the talar articular facets to each other and the tilt of the calcaneocuboid joint to the longitudinal axis of the calcaneus) are predictive of arch height (r2 = .29-.44 p ≤ .001). All angular measurements of the talus and all examined linear measurements of both the talus and calcaneus were not predictive of arch height. DISCUSSION: These results suggest that certain angular measurements of the calcaneus are associated with arch height in the modern human foot. While this information is useful in the interpretation of hominin pedal remains, the relationship of the morphology of these bones, as well as other bones of the foot, to arch height is complex, requiring further investigation.

The Relationship Between Angular Osteologic and Radiographic Measurements of the Human Talus and Calcaneus.

BACKGROUND: Radiographic imaging of the foot is commonly performed when medical evaluation is indicated. Angular measurements between bones may be assessed as part of the examination for trauma and foot biomechanics. However, angular relationships between surfaces of the physical bone as they compare with the bone's radiographic image has had limited investigation. METHODS: For this study, 54 human feet from amputated limbs were imaged in standard radiographic views and skeletonized. Selected angular measurements were taken on each skeletonized talus and calcaneus and were compared with those taken from radiographic images using paired Student t tests and linear regression analysis. RESULTS: Transverse plane measurements of the talus were not significantly different (P ≥ .05), associating strongly (r2 = 0.67-0.75; all P < .001). Most transverse and sagittal plane measurements of the calcaneus were not significantly different (P ≥ .05), with transverse plane measurements more strongly associated (r2 = 0.70-0.77; all P < .001) than sagittal plane measurements (r2 = 0.35-0.78; all P < .001). CONCLUSIONS: Selected angular measurements of the talus and calcaneus taken from radiographic images can be compared quantitatively with the physical bone, demonstrating that angular measurements from radiographic images provide useful information concerning both of these bones. This knowledge can be applied to the understanding of the morphology of the calcaneus and talus as it relates to human foot biomechanics and should also be of use in the interpretation of the human fossil pedal record.

The Relationship Between Linear Osteological and Radiographic Measurements of the Human Calcaneus and Talus.

Plain radiographs of the foot are a common form of examination in individuals when medical evaluation is indicated. Their availability makes them useful for studying human variation where large sample sizes are crucial. Calcaneal and talar morphology are critical in the understanding of human foot form and function, but few studies have examined the accuracy of linear measurements of these bones taken from radiographs. If linear measurements are to be used in quantitative analysis, their accuracy must first be demonstrated. For this study, 54 human feet from amputated limbs were imaged in standard radiographic views and skeletonized. Selected linear measurements were made on each skeletonized talus and calcaneus. Corresponding landmarks were identified on the radiographic images and the distances between these points determined. Using the measurements taken from the physical bone, the accuracy of the radiographic measurements was evaluated employing paired Student's t-tests and correlation analysis. Most measurements were not significantly different (P ≥ 0.05). Overall, the sagittal plane measurements were correlated (r2 > 0.61-0.88, all P < 0.001) with the radiographic measurements; transverse plane measurements less so (r2 = 0.20-0.63, P < 0.001). These results demonstrate that measurements from radiographic images provide useful information concerning both the calcaneus and talus, indicating that radiographs of living individuals can be evaluated quantitatively and compared to osteology collections of modern humans. This information can be applied to the understanding of functional anatomy of the modern human foot, interpreting the hominin fossil pedal record, and establishing identification in forensic analysis. Anat Rec, 2017. © 2017 Wiley Periodicals, Inc. Anat Rec, 301:21-33, 2018. © 2017 Wiley Periodicals, Inc.