Which nerve root is associated with sensations in the anterior/ medial thigh and the patellar reflex, as described?

Which nerve root is associated with sensations in the anterior/ medial thigh and the patellar reflex, as described?

• A. L2-3
• B. L4
• C. S1
• D. L5

Answer: (A)

Sensation over the anterior and medial thigh is carried mainly by the L2 and L3 dermatomes. In this description, the same nerve roots are tied to the described reflex finding, so the pair of roots that best accounts for both the sensory region and the reflex response in this context are L2 and L3. The other options don’t align with the anterior/medial thigh sensory map as cleanly: for example, the L4 region more typically relates to the knee/patellar reflex itself, but not the anterior thigh sensation described here, and S1 or L5 would not cover the anterior thigh in the same way.

Sensation over the anterior and medial thigh is carried mainly by the L2 and L3 dermatomes. In this description, the same nerve roots are tied to the described reflex finding, so the pair of roots that best accounts for both the sensory region and the reflex response in this context are L2 and L3. The other options don’t align with the anterior/medial thigh sensory map as cleanly: for example, the L4 region more typically relates to the knee/patellar reflex itself, but not the anterior thigh sensation described here, and S1 or L5 would not cover the anterior thigh in the same way.