Urinary striated sphincter: what is its nerve supply?

Area of Science:

• Neuroscience
• Urology
• Anatomy

Background:

• The precise innervation of the voluntary urinary sphincter has been a long-standing debate in scientific literature.
• Understanding this nerve supply is crucial for diagnosing and treating urinary incontinence and related disorders.

Purpose of the Study:

• To definitively clarify the nerve supply to the voluntary external urinary sphincter.
• To identify the specific neural pathways and central nervous system centers involved in voluntary control of the sphincter.

Main Methods:

• Utilized retrograde axonal transport techniques, specifically employing horseradish peroxidase (HRP) as a tracer.
• Injected HRP into the voluntary external urinary sphincter and the cut end of the pudendal nerve.
• Traced the HRP transport to identify the origin of the nerve supply within the central nervous system.

Main Results:

• Horseradish peroxidase transport from both the external sphincter and the pudendal nerve converged on the same neurons.
• These neurons were located in the dorsolateral column of the spinal cord.
• Successfully labelled and identified the pudendal nucleus as the motor center for the voluntary urinary sphincter.

Conclusions:

• The pudendal nucleus serves as the primary motor center for the voluntary urinary sphincter.
• Retrograde axonal transport is an effective method for resolving controversies in neuroanatomy.
• This study provides a clear understanding of the neural control of the external urinary sphincter.