<unk>  are accessory pathway taking the form of atrio-Hisian fibers.  These are atrial fibers, normal in structure, which bypass the AV node and  penetrate into the upper margin of the left side of the bundle of His in its mid part.
Brechenmacher fibers
Mahaim fibers
Horror vacui
Schmidt-Lanterman incisures
James fibers
Mees' lines
Neurofibrillary tangle
Microtia