**Question:** A patient operated for direct inguinal hernia develops anesthesia at the root of the penis and adjacent part of the scrotum. The nerve likely to be injured is:

A. Hypogastric Nerve
B. Genitofemoral Nerve
C. Sacral Nerve
D. Superficial Femoral Nerve

**Core Concept:**

Inguinal hernia surgery can occasionally result in injury to nerves supplying sensory and motor function to the genitalia, particularly during the repair of direct inguinal hernias. The inguinal region is innervated by several nerves, and identifying the correct one is essential for understanding the symptoms and management of the injury.

**Why the Correct Answer is Right:**

The correct answer is **B. Genitofemoral Nerve**. The genitofemoral nerve is a sensory branch of the lumbar plexus, which supplies sensory innervation to the inguinal region, including the root of the penis and the adjacent part of the scrotum. During direct inguinal hernia repair, excessive dissection or injury to the nerve can lead to the symptoms described.

**Why Each Wrong Option is Incorrect:**

A. Hypogastric Nerve (also known as the inferior hypogastric plexus) is a mixed nerve supplying both sensory and motor function to the lower abdomen, vulva, and anus, not the genital region.

C. Sacral Nerve is responsible for innervating the anal sphincter, rectum, and lower limbs, not the genital region.

D. Superficial Femoral Nerve is responsible for sensory function in the thigh, knee, and lower leg, not the genital region.

**Clinical Pearl:**

Understanding the structure and function of the genitofemoral nerve is crucial when assessing patients with post-inguinal hernia surgery symptoms. Overextension of the dissection during surgery or direct injury can lead to loss of sensation in the genital region, as seen in this question.

Recognizing this injury is essential for accurate diagnosis and appropriate management, including surgical repair or nerve grafting in severe cases.