Images of muscle biopsies reveal a mosaic pattern of two (slow-twitch and fast-twitch) fibre-types. An analysis of such images can indicate some neuromuscular disorder. We briefly review some methods which analyse the arrangement of the fibres (e.g. clustering of fibre type) and the fibre sizes. The proposed methodology uses the cell centres as a set of landmarks from which a Delaunay triangulation is created. The shapes of these (correlated) triangles are then used in a test statistic, to ascertain normality of a muscle. Our “normal muscle” model supposes that the fibres are hexagonal (so that the triangulation is made up of equilateral triangles) with a perturbation of specified isotropic variance of the fibre centres. We obtain the distribution of the test statistic as an approximate function of a χ 2 random variable, so that a formal test can be carried out.
