Figure 6.

Summary diagram. A normal external urethral sphincter (EUS) is innervated by the motor neurons of the pudendal nerve (PN), as shown in (A). An injured EUS and PN has decreased innervation, as shown in (B). Treatments that enhance the BDNF regenerative pathway could enhance neuroregeneration of the PN and re-innervation of the EUS, as shown in (C). Unassisted regeneration of the PN results in increase in muscle fibers innervated by a single motor neuron, as shown in (D). With time after unassisted partial regeneration, axons atrophy with aging, as shown in (E).