Results. The LP is a fan-shaped, non-pennate muscle with marked architectural variation. The superior head (SH) origin is limited to the superomedial margin of the inferior orbital fissure (infratemporal aspect). Sixty-two percent of SH bundle insertions were into the TMJ disc-capsule-complex. There were a mean of 130 fibre bundles per specimen, and the mean overall length of digitized fibre bundles was 26.4 mm. Specimens with displaced discs (35%) exhibited shorter and more LP bundles, but without statistically different muscle insertion patterns.Purpose. To describe the architecture of the human lateral pterygoid (LP) muscle at the individual fibre bundle level.Conclusions. The LP shows significant architectural variation. Muscle insertion pattern was not a predictor of disc displacement. SHLP origin is different from that reported in previous literature.Materials and methods. Twenty cadaveric LP muscles were dissected. Individual fibre bundles were dissected and digitized, followed by 3-D visualization and quantification of architecture.