What is the primary function of the hypogastric nerve?

The primary function of the hypogastric nerve is to facilitate urine retention. This nerve plays a crucial role in the sympathetic nervous system's control over bladder functions. When stimulated, the hypogastric nerve inhibits bladder contraction and promotes the relaxation of the detrusor muscle, allowing the bladder to fill without the urge to void. It also acts to maintain contraction of the internal urethral sphincter, which prevents urine from leaking into the urethra, contributing to overall retention.

The reduction in bladder contraction and the relaxation of the internal sphincter are vital for maintaining continence, particularly during states where it is inappropriate to urinate. Therefore, the role of the hypogastric nerve is essential for the storage phase of micturition, ensuring that urine is retained until the appropriate time for voiding.