Longitudinal fibre splitting inmuscular dystrophy: aserial cinematographic study

SUMMARY Atechnique ofblock surface-staining andserial cinematography was modified toreview serial sections ofnormal anddystrophic muscle fromtheBarHarbor129Restrain ofmiceas a preliminary study offibre splitting indystrophic muscle. Usingthis technique, muscle fibres were reconstructed forup to1-5mm oftheir length without difficulty. Split fibres were identified only whentheactual separation offibres was observed. Splitting was seentobeasignificant causeofthe variations infibre diameter andwas attimesresponsible fortheformation ofgroups ofsmall atrophic fibres whichresembled those seenindenervation atrophy. Complex multiple splitting and recombination ofdaughter andparentfibres was alsoobserved andreconstructed toscale. These results may haveconsiderable significance fortheinterpretation ofphysiological dataon both humanandmurine dystrophic muscle.