College of Massage Therapists of British Columbia (CMTBC) Practice Exam

Which dermatome correlates with the obturator nerve cutaneous zone?

1. L1

2. L2

3. L3

4. L4

The correct answer is: L2

The obturator nerve is primarily responsible for innervating the medial compartment of the thigh, and it has a specific cutaneous zone associated with it. The correct choice indicating the dermatome that correlates with the obturator nerve cutaneous zone is L2. Dermatomes are areas of skin that are mainly supplied by a single spinal nerve root. The L2 dermatome includes the lateral aspect of the thigh, where the sensory distribution of the obturator nerve can be found. Understanding the relationship between spinal nerves, their corresponding dermatomes, and what muscle groups they innervate is essential for accurately identifying the correct options in questions about nerve pathways. Knowing this, one might note that other options, such as L1, L3, and L4, correspond to different areas and functions in the lower limb. L1 primarily relates to the groin region, L3 references the knee area and the upper part of the medial thigh, while L4 covers the medial side of the leg and part of the foot. Each of these dermatomes has a distinct relationship with different nerves, further emphasizing the significance of knowing the correct spinal levels associated with each zone.