Which injury is a neurogenic cause of detrusor atony?

Detrusor atony, a condition characterized by reduced muscular tone in the bladder, can occur due to various neurogenic causes. One significant neurogenic cause is a sacral spinal cord or pelvic nerve injury. This type of injury directly impacts the sacral nerves, which are critical for bladder control. The sacral spinal cord contains neurons that facilitate the contraction of the detrusor muscle during urination; thus, any disruption to these nerves can lead to impaired bladder function and a lack of detrusor tone, resulting in atony.

In contrast, proximal femoral fractures, thoracic spinal cord injuries, and distal extremity trauma do not primarily affect the sacral nerves or the neural pathways that control bladder contraction, making them less relevant causes of detrusor atony. The thoracic spinal cord mainly influences upper body function rather than the lower pelvis. Therefore, injuries to the sacral region are specifically linked to disturbances in bladder function, affirming that sacral spinal cord or pelvic nerve injury is the correct answer.