jointAngle: Calculate joint angles (in degrees) from XYZ coordinate data

In MorphoFun/kraken: Analyses for bone biomechanics

Calculate joint angles (in degrees) from XYZ coordinate data

Description

Calculates the angle of a joint (in degrees), formed by three points with XYZ coordinates.

Usage

jointAngle(P1, P2, P3)

Arguments

P1	A data.frame of numeric values containing the X, Y, and Z coordinate data, respectively, for the first point (e.g, the shoulder)
P2	A data.frame of numeric values containing the X, Y, and Z coordinate data, respectively, for the second point, which is assumed to be the vertex of the angle (e.g, the elbow)
P3	A data.frame of numeric values containing the X, Y, and Z coordinate data, respectively, for the third point (e.g, the wrist)

Details

These procedures follow the methodology used in Kawano and Blob (2013) and Kawano et al. 2016 to calculate angles formed about the limb joints in animals.

References

Kawano SM, Blob RW. 2013. Propulsive forces of mudskipper fins and salamander limbs during terrestrial locomotion: implications for the invasion of land. Integrative and Comparative Biology 53(2): 283-294. https://academic.oup.com/icb/article/53/2/283/806410/Propulsive-Forces-of-Mudskipper-Fins-and

Kawano SM, Economy DR, Kennedy MS, Dean D, Blob RW. 2016. Comparative limb bone loading in the humerus and femur of the tiger salamander Ambystoma tigrinum: testing the "mixed-chain" hypothesis for skeletal safety factors. Journal of Experimental Biology 219: 341-353. http://jeb.biologists.org/content/219/3/341

"R - Comute Cross Product of Vectors (Physics)" answer posted by user Kevin on April 22, 2016. https://stackoverflow.com/questions/36798301/r-compute-cross-product-of-vectors-physics

"how to calculate the Euclidean norm of a vector in R?" answer posted by user joran on June 7, 2012. https://stackoverflow.com/questions/10933945/how-to-calculate-the-euclidean-norm-of-a-vector-in-r

Examples

shoulder <- matrix(c(0.006305306, 0.006526961, 0.006747555, -0.08206114, -0.08207707, -0.08207049, 0.006997669, 0.006980824, 0.006975157), 3, 3)
elbow <- matrix(c(0.007826633, 0.007959096, 0.008068560, -0.07183020, -0.07185459, -0.07186337, 0.005754819, 0.005764666, 0.005774707), 3, 3)
wrist <- matrix(c(0.01164592, 0.01160690, 0.01157642, -0.07348876, -0.07345559, -0.07342105, -0.000631402, -0.000671288, -0.000709513), 3, 3)

elbowAngle <- jointAngle(P1 = shoulder, P2 = elbow, P3 = wrist)

MorphoFun/kraken documentation built on July 2, 2022, 1:13 p.m.