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

Which area does the radial nerve primarily supply sensation to?

1. Anterolateral arm

2. Medial hand

3. Posterior upper limb

4. Lateral shoulder

The correct answer is: Posterior upper limb

The radial nerve primarily supplies sensation to the posterior upper limb, which includes the posterior aspect of the arm and forearm. This area encompasses the skin over the triceps muscle, and the radial nerve continues down into the forearm to provide sensory innervation to the dorsal side of the hand, specifically the first three and a half fingers, except for the tips of those fingers. Understanding the function of the radial nerve is crucial because it plays a key role in both motor and sensory functions in the upper limb. Motor branches from the radial nerve innervate muscles responsible for extension of the arm and forearm. The sensory branches provide important feedback from the skin regarding the position and state of the arm, which is essential for coordinated movements and protecting the limb. The other options do not accurately represent the primary sensory distribution of the radial nerve. For instance, the anterolateral arm is primarily supplied by different nerves, such as the musculocutaneous nerve. The medial hand is generally innervated by the ulnar nerve, especially regarding the little finger and the adjacent part of the ring finger. The lateral shoulder is predominantly supplied by the axillary nerve. Therefore, the correct choice reflects the specific area where the radial nerve's sensory function is prevalent