Related Experiment Video
Updated: Jul 15, 2026
Detrusor Underactivity Model in Rats by Conus Medullaris Transection
Published on: August 28, 2020
Pudendal nerve stimulation evokes reflex bladder contractions in persons with chronic spinal cord injury
Paul B Yoo1, Stephen M Klein, Neil H Grafstein
1Department of Biomedical Engineering, Duke University, Durham, NC 27708-0281, USA. paul.yoo@duke.edu
Aims:
Although electrical stimulation of the pudendal nerve has been shown to evoke reflex micturition-like bladder contractions in both intact and spinalized cats, there is little evidence to suggest that an analogous excitatory reflex exists in humans, particularly those with spinal cord injury (SCI). We present two cases where electrical activation of pudendal nerve afferents was used to evoke excitatory bladder responses.
Subjects And Methods:
A percutaneously placed catheter electrode was used to electrically stimulate the pudendal nerve trunk in two males with SCI. The response was quantified with recorded changes in detrusor pressure and EMG activity of the external anal sphincter.
Results:
In both individuals, frequency specific (f = 20-50 Hz) activation of the pudendal nerve trunk evoked excitatory bladder contractions that also depended on the stimulus amplitude and bladder volume.
Conclusion:
The results suggest that selective activation of the perineal branches of the pudendal nerve may further augment the excitatory reflex evoked by electrical stimulation.
Related Concept Videos
01:26The Micturition Reflex
The process begins with bladder filling, where the bladder wall stretches as urine accumulates. This stretching activates the urine storage reflex, mediated by the sacral spinal segments and the pontine storage center. Efferent sympathetic impulses stimulate the detrusor muscle to relax and the internal urethral sphincter to contract, facilitating urine...
01:22Somatic Spinal Reflexes
One of the most well-known somatic spinal reflexes is the stretch reflex, which is activated by the sudden stretching of a muscle. This reflex involves the activation of specialized sensory receptors called muscle spindles, which are located in the muscle tissue and detect changes in the length and speed of muscle contractions. When a muscle is suddenly...
01:23Urinary Bladder
In males, the bladder is situated in front of the rectum, while in females, it is positioned anterior to the vagina and uterus. The bladder floor contains an inverted triangular area called the trigone, defined by the two ureteric...
01:21Spinal Nerves: Plexus II
The Lumbar Plexus
The lumbar plexus is situated within the lumbar region of the back and is primarily formed by the first four lumbar spinal nerves (L1 to L4). This plexus extends its branches into several nerves, including the...
01:14Spinal Cord Injury ll: Pathophysiology