Fig. 6. Schematic representations showing three types of muscle fiber crossing. The crossing is hypothesized between two muscles with quite different vectors (the vectors cross at almost right angle) such as seen in the levator and lateral tractor. A striated muscle fiber or muscle cell (black) is covered by the basal lamina and surrounded by the endomysium (orange). Usually, when two muscles cross, 1) muscle fibers are bundled by the perimysium (green) and the bundles cross or 2) a bundle crosses a solitary muscle fiber. However, in limited sites, a solitary muscle fiber is likely to cross another fiber with the endomysium-to endomysium contact.
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