**Question:** A 19-year-old man met with an accident and sustained an internal injury in the abdomen. The fibres in the Nervus erigentes are lesioned, leading to disability/loss of the following function:

A. Erectile function
B. Sphincter control
C. Vaginal dilation
D. Urinary continence

**Correct Answer:** A. Erectile function

**Core Concept:** The Nervus erigentes, also known as the dorsal branch of the penile nerve, is a crucial structure involved in the erectile function of the penis.

**Why the Correct Answer is Right:** The Nervus erigentes plays a significant role in the cavernous nerve function, which is essential for the development of erection during sexual arousal. Lesions to this nerve can lead to a loss of erectile function in the affected individual.

**Why Each Wrong Option is Incorrect:**

B. Sphincter control (Option B) is a separate structure, the external urethral sphincter, controlled by the pelvic floor muscles (sphincterium externum). Lesions to the Nervus erigentes do not affect sphincter control.

C. Vaginal dilation (Option C) is controlled by the internal urethral sphincter, which is separate from the Nervus erigentes. Lesions to the Nervus erigentes do not cause issues with vaginal dilation.

D. Urinary continence (Option D) is regulated by the pelvic floor muscles and the internal urethral sphincter, distinct from the Nervus erigentes. Lesions to the Nervus erigentes do not directly cause urinary continence issues.

**Clinical Pearl:** In cases where patients suffer from injuries to the abdomen, it is essential to evaluate for potential damage to the Nervus erigentes and its role in erectile function to avoid misdiagnosis and provide appropriate treatment options.