Damage to which of the following nerves leads to sensory loss on adjacent sides of the great and second toes and impaired dorsiflexion of the foot?
**Core Concept**
The question is testing the student's knowledge of the motor and sensory innervation of the foot. The nerves responsible for the motor function of dorsiflexion and the sensory innervation of the great and second toes need to be identified.
**Why the Correct Answer is Right**
The correct answer is the common peroneal nerve (also known as the common fibular nerve). This nerve is a branch of the sciatic nerve and is responsible for the motor function of dorsiflexion of the foot and the sensory innervation of the great and second toes. The common peroneal nerve has both sensory and motor fibers that run through it, making it a mixed nerve. Damage to this nerve can lead to weakness or paralysis of the muscles responsible for dorsiflexion, resulting in foot drop, and sensory loss on the adjacent sides of the great and second toes.
**Why Each Wrong Option is Incorrect**
* **Option A:** The posterior tibial nerve is responsible for the sensory innervation of the sole of the foot and the motor function of plantarflexion, not dorsiflexion.
* **Option B:** The sural nerve is a sensory nerve that provides innervation to the lateral aspect of the foot and the little toe, but it is not responsible for the motor function of dorsiflexion.
* **Option D:** The saphenous nerve is a sensory nerve that provides innervation to the medial aspect of the leg and foot, but it is not responsible for the motor function of dorsiflexion.
**Clinical Pearl / High-Yield Fact**
The common peroneal nerve is often damaged at the fibular head, which is a common site for nerve compression due to tight clothing, casts, or other external pressures. This can lead to a condition known as peroneal nerve palsy, which results in foot drop and sensory loss on the adjacent sides of the great and second toes.
**Correct Answer:** C. The common peroneal nerve.