A barefoot child steps on some glass on the sole of his foot and complains of numbness of the small toe. He has injured which nerve?
## **Core Concept**
The question tests knowledge of the sensory innervation of the foot, specifically the nerves responsible for the sensation of the toes. The sensory nerves of the foot are derived from the peripheral nervous system, originating from the lumbar and sacral nerve roots.
## **Why the Correct Answer is Right**
The correct answer, the **plantar digital nerves**, specifically the one innervating the small toe, is responsible for the sensation of the small toe. These nerves are branches of the **medial plantar nerve** (or sometimes the **lateral plantar nerve** for the lateral part of the foot), which themselves are branches of the **tibial nerve**. The numbness of the small toe indicates damage to the nerve supplying it.
## **Why Each Wrong Option is Incorrect**
- **Option A:** This option is incorrect because it does not specify a nerve that could plausibly cause isolated numbness of the small toe. Without specifying the nerve, it's impossible to assess its relevance.
- **Option B:** This option is incorrect because, similar to option A, it lacks specificity regarding the nerve involved.
- **Option D:** This option is incorrect because it also lacks detail and does not directly relate to the sensory innervation of the small toe.
## **Clinical Pearl / High-Yield Fact**
A key point to remember is that the **medial plantar nerve** supplies the medial three and a half toes (including the medial side of the fourth toe), while the **lateral plantar nerve** supplies the lateral one and a half toes (including the small toe and the lateral side of the fourth toe). Therefore, numbness of the small toe would likely involve the **lateral plantar nerve** or one of its **plantar digital nerve** branches.
## **Correct Answer:** . **plantar digital nerves**