Further observations concerning the motor innervation of the tensor tympani muscle of the cat

The cat tensor tympani muscle presented an uncommon ultrastructural organization of neuromuscular junctions compared with those in the other striated muscles. In cross sections, individual neuromuscular junctions had very extended contact area of the nerve terminal and muscle fiber, the terminal bouton was covering as a "calyx" the postjunctional muscle fiber. Long basal lamina was interposed between them. The sarcolemma at the level of the nerve terminal had multiple infoldings along its length, or smooth postjunctional muscle membrane was found beneath endings on both fiber types.