What does the pudendal nerve primarily innervate?

The pudendal nerve primarily innervates the external urethral sphincter, which is crucial for voluntary control over urination. This nerve plays a significant role in the somatic control of the external genitalia and perineal structures, allowing for fine motor control of the sphincter to enable or inhibit the voiding of urine. The external urethral sphincter is a striated muscle that is under voluntary control, unlike the internal sphincter, which is governed by autonomic innervation.

While other structures listed have their own nerve supply—such as the detrusor muscle, which is innervated by the pelvic splanchnic nerves for bladder contraction, and the pelvic floor muscles—these do not receive primary innervation from the pudendal nerve like the external urethral sphincter does. The internal urethral sphincter is also primarily controlled by autonomic pathways rather than the somatic pathways associated with the pudendal nerve. Understanding the role of the pudendal nerve is essential for grasping the neuromuscular control of micturition and the coordination of bladder and sphincter function.