Analysis of Three Commonly Used Tibia Length Measurement Techniques

Abstract

This study analyzes three tibia length measurement techniques on a sample of 107 tibiae. Two of the techniques meet published criteria by resting the tibia on its posterior surface with the longitudinal axis parallel to an osteometric board. The third technique does not adequately keep the longitudinal axis parallel to the board. Statistical analyses show low levels of interobserver error for all techniques and statistically significant differences between the third technique and the other two techniques. Results report a maximum difference of 6 mm between measurement techniques with the third technique having greater than 95% directional bias. A survey sent out to the American Academy of Forensic Sciences forensic anthropology community reported more than 50% of respondents having been taught the third technique when an osteometric board with a slot/hole is not available. The intermixing of the third technique with the other two has likely contributed to higher levels of interobserver error in tibia length measurements.

Measuring the Tibia: Trotter’s Error Revisited

“…This acceptance is likely due to Trotter and Gleser’s (1) large sample based on antemortem heights that was best suited for purposes of living stature estimation. Unfortunately, their definition can be implemented in different ways that can result in average differences of almost 3 mm and maximum differences up to 6 mm (16). In view of variation that exists even when observers are ostensibly following the same definition, the most prudent course for forensic practitioners is to avoid the tibia, if possible, in favor of the fibula as an indication of lower leg length.…”

“…Importantly, Trotter's definition mentions placing the end of the malleolus against the vertical board and applying a freely movable block at the other end. As such it is essentially the same as technique B in Lynch et al (16) where the sliding end of the osteometric board is used as a block. As nearly as we can determine what Trotter actually measured is unique, never defined or used before or since.…”

Estimating the entire length of the fragmentary tibia with proximal and distal dimensions

“…Chibba et al (2007) formulated the estimation of the maximum tibial length and stature using five measurements from the proximal tibia and only one measurement from the distal tibia in South African populations. Lynch et al (2019) took the tibia length measurements on an osteometric board. They used three techniques for the tibia length.…”

Generalized Network Structured Models with Mixed Responses Subject to Measurement Error and Misclassification

“…For model (13), we take $$\sigma _e=0.77$$ according to Lynch et al. (2019); in addition, we set $$\sigma _e$$ to be 0.72 or 0.82. For model (12), we consider the setting with $$\alpha _{0z}=\alpha _{1z}=0$$ and $$\alpha _{00}=\alpha _{01}=-2.5,-1.5$$, or −0.5, respectively, yielding the misclassification rate to be 5%, 10%, and 20%.…”