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

What is the primary sensory function of the axillary nerve?

1. Medial hand

2. Lateral shoulder

3. Anterior arm

4. Posterior upper limb

The correct answer is: Lateral shoulder

The axillary nerve is primarily responsible for providing sensory innervation to the lateral aspect of the shoulder. This region is significant because it encompasses the area over the deltoid muscle, which is crucial for shoulder movement. When the axillary nerve is functioning properly, it allows for sensation in this specific area, particularly over the skin that covers the upper part of the shoulder. Understanding the role of the axillary nerve can be further contextualized by recognizing its routes and anatomical relationships. The nerve arises from the brachial plexus and travels through the quadrangular space, innervating both the deltoid and teres minor muscles along with providing the sensory function to the lateral shoulder. Damage or injury to the axillary nerve commonly presents with sensory loss or numbness in this area, reinforcing its primary role in shoulder sensation. The other choices refer to different areas of the upper limb where other nerves are responsible for sensory functions. For example, sensations in the medial hand are attributed to the ulnar nerve, the anterior arm is primarily supplied by the musculocutaneous nerve, and sensations in the posterior upper limb are supplied mainly by the radial nerve. This differentiation emphasizes the specific role of the axillary nerve as it pertains to the lateral shoulder area