Skeletal Muscle atrophy is a hallmark change associated with muscle degeneration, disuse atrophy and neurogenic atrophy. Fiber type grouping is a hallmark pathologic change associated with motor neuron atrophy and synaptic loss, see [1].
These APPs identify individual muscle fibers in whole slide images and calculate the lesser diameter for each fiber. This is done for both stained and unstained fibers allowing quantification of muscle fiber diameter by myosin fiber type. In type I myosin predominant muscle, the clustering of type II fibers can be assessed as a measure of synaptic denervation and reinnervation.