Analysis of human back shape using surface curvatures

doi:10.1016/0021-9290(82)90059-8

Journal of Biomechanics

Volume 15, Issue 5, 1982, Pages 379-390

https://doi.org/10.1016/0021-9290(82)90059-8 Get rights and content

Abstract

A method for the evaluation of surface measurements of the human back is presented. A shape analysis is carried out in terms of surface curvature. This is calculated using differential geometry of surfaces. Similar to other invariant shape parameters, the surface curvature does not depend on a coordinate system and is thus independent of the patient's position. The advantages of such an invariant shape analysis are discussed and first results are presented.

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Cited by (63)

The influence of smartphone use on spinal posture – A laboratory study
2021, Gait and Posture
Citation Excerpt :
While performing the respective smartphone tasks, the spinal posture and pelvic position during standing and while walking on a treadmill was measured using a surface topography system (Formetric 4Dmotion, Diers International GmbH, Schlangenbad, Germany). This system allows a radiation- and contact-free examination of the spinal posture and pelvic position [19–25]. The spinal and pelvic parameters used in this study have been described previously [26–28].
Smartphones have become increasingly more popular and complicated tasks can be performed with these devices. However, the increasing use is associated with shoulder and neck pain, as well as with psychological addiction.
Do different smartphone tasks lead to changes in spinal posture and pelvic position? Is there a relationship between smartphone addiction and changes in posture?
A cross-sectional study including 50 participants was performed. Test subjects completed the Smartphone Addiction Scale and the SF-36 health questionnaire. Subjects spinal posture and pelvic position during different smartphone tasks were measured through a surface topography system. The different tasks were: standing in an upright position, simulating a phone call, texting with one or two hands during standing or while walking on a treadmill. Paired T-tests and ANOVA tests were performed to evaluate differences. The Kendall rank test was used to investigate the association between clinical scores and changes in spinal posture.
All smartphone tasks lead to a significant increase in thoracic kyphosis and trunk inclination during standing and while walking. A significant increased lumbar lordosis was also found. Texting with one or two hands correlated with increased surface rotation. No associations between smartphone addiction and changes of the spinal posture were reported.
This represents the first surface topography study that investigated the influence of different smartphone tasks on the spinal posture and pelvic position during standing and while walking. With the results of this study we demonstrated that smartphone use leads to significant changes of sagittal and frontal spine parameters. Further research should focus on the evaluation of possible detrimental effects of long-term smartphone use on the spinal posture and on the development of preventive measures.
Dynamic evaluation of simulated leg length inequalities and their effects on the musculoskeletal apparatus
2019, Gait and Posture
Citation Excerpt :
All measurements were conducted with a surface topography measuring system (Formetric 4D motion, Diers International GmbH, Germany). This system allows a radiation- and contact-free examination of the pelvic position and spinal posture [11]. It consists of a light projector and a digital video camera, which work together as a stereooptical pair [8].
Leg length inequalities (LLI) are a common problem in medicine. So far, the diagnosis and treatment are performed under static conditions. Surface Topography (ST) is an optical, non-invasive technique that uses the principle of triangulation to measure spinal posture and pelvic position. This technique offers the opportunity to detect and treat LLIs and their effects under dynamic conditions.
question The aim of the study is to show that ST can detect simulated LLIs under dynamic conditions and to prove if there are differences between the effects on the human body under static and dynamic conditions.
In the clinical study a total of 30 test subjects were examined with a ST measuring device. LLIs (1 to 4 cm) were simulated using a custom- built sandal and insoles of various thickness. The pelvic obliquity, the surface rotation and lateral deviation of the spine were detected on a treadmill under static and dynamic conditions (3 km/h).
Under static and dynamic conditions LLIs lead to a significant increase of all measured parameters. The pelvic obliquity reaches a significant level of p < 0.0001 under static and p = 0.0001–0.0421 under dynamic conditions. However, for all examined parameters the magnitudes of the parameters under dynamic conditions were smaller than under static conditions.
The study showed that simulated LLIs also have a significant effect on the human pelvis and spine under dynamic conditions, but with a smaller magnitude than under static conditions. The human individuum is a dynamic one. Because of that, for the future it should be of great interest to use dynamic measurements to detect and treat LLIs to provide an over correction of LLIs.
Reliability and validity of 4D rasterstereography under dynamic conditions
2011, Computers in Biology and Medicine
Citation Excerpt :
Rasterstereography is a method for stereophotogrammetric surface measuring of the back, which was developed in the 80s by Hierholzer and Drerup [9,10]. Based on the principle of triangulation it allows a contact- and radiation-free determination of the body surface [5,11–16]. Two cameras, from two different angles, hereby record the back shape.
Purpose of this study was to evaluate the reliability and validity of 4D rasterstereography under dynamic conditions. Therefore simulated anatomical fixed points on a wooden plate were measured during different movements. Seven different motion patterns in all three angles of space were evaluated. The simulated parameter trunk length was measured with an accuracy of 3.58 mm (SD±3.29 mm) and the dimple distance was detected with an accuracy of 0.88 mm (SD±1.04 mm). With this rasterstereographic prototype it is possible to examine dynamically the spinal posture with adequate accuracy.
Tibial torsion measurement by surface curvature
2005, Clinical Biomechanics
Background. Tibial torsion is the angle between the transverse axes of the proximal and distal tibial articular surfaces. It measures the degree of twisting of the tibia around its own longitudinal axis. The accurate measurement on the magnitude of tibial torsion is of great use in monitoring derangements. It is also useful as a baseline in the event of surgical intervention. Various methods have been developed but none of them have gained wide acceptance. Even the CT scan technique, which is considered the “gold standard”, produces varying results when executed by different researchers. A quick, objective and non-invasive method is thus very much needed for the effective monitoring of tibial torsion in clinical environments.
Methods. Eighteen adult men’s lower legs were scanned by a laser scanner to give the surface coordinates of the leg surfaces. By calculating curvature maps of legs from the 3D coordinates, stable anatomical landmarks such as the lateral and medial malleoli can be located. The angle indicating the degree of tibial torsion can then be derived from these landmarks.
Findings. The objective determination of the various anatomical landmarks results in a reproducible measure of tibial torsion. The results obtained in this study are generally in agreement with the measurements reported previously.
Interpretation. The reproducibility of the results allows for the objective observation, monitoring and comparison of tibial torsion over time and across subjects. It allows also for the development of a system of measurement that is fast, convenient, accurate and radiation-free.
3D characterization and localization of anatomical landmarks of the foot by FastSCAN
2004, Real-Time Imaging
Anatomical landmarks
Biomechanics
Curvature maps
The landmarks on the body surface are important to shape and motion analysis. It is much better if the landmarks are anatomical ones, which are independent of position and coordinate system. The objective of this method is to present an easy-implemented method for extracting anatomical landmarks on the cylindraceous body surface which could be used in motion analysis or in medical treatment. The surface is scanned by FastSCAN (Polhemus, Colchester, Vermont, USA) and described by scattered three-dimensional surface points. The method provides the estimation of second-order derivatives by way of least-squares surface fitting to calculate the Gaussian curvature and mean curvature. To separate convexity from concavity, the Koenderink shape index maps of foot and leg are given as examples. The landmarks formed by underlying muscles and skeletal structures such as the malleoli distinguish themselves clearly on the Koenderink shape index maps. Minutes after the foot and leg are scanned, the curvature maps of the foot and leg provide the shape information and the loci of landmarks avail the statistical shape analysis as well as foot underside deformation analysis. Furthermore, the anatomical landmarks around the knee and ankle, defining the transcondylar and transmalleolar axis, make it possible to calculate the tibial torsion by this non-invasive way. Generally, this method is fast and accurate. However, it gives some inaccurate results on the patch edge, which should be interpreted with caution, when it is applied on a surface patch in other occasions because of a small number of points unevenly distributed in the operator. Presently, the method is computationally intensive although the time can be reduced to a few seconds at the sacrifice of image resolution. Further efforts will be made to get the real-time information.
Wound measurement by curvature maps: A feasibility study
2006, Physiological Measurement

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Analysis of human back shape using surface curvatures

Abstract

Ueberlegungen zur nomografischen Auswertung von Moiré-Topogrammen

Internal Report No. 20

A procedure for the numerical analysis of Moiré topograms

Int. Arch. Photogramm., Hamburg.

A stereophotogrammetric method for the measurement of body surfaces using a projected grid

Rasterstereografie—Teil 2: Krümmungsanalyse

Internal Report No. 22