American Board of Surgery Qualifying Exam (ABS QE) Practice Test 2025 - Free Surgery Exam Practice Questions and Study Guide

The intercostobrachial nerve is a sensory nerve that arises from the second intercostal nerve and primarily supplies sensation to the medial aspect of the arm and axilla. Its role is significant in providing cutaneous sensory innervation to these areas, which is why option B is the correct choice.

Understanding the function of the intercostobrachial nerve is important in clinical settings, particularly during surgical procedures involving the axillary region or when assessing sensory loss due to nerve injury. The sensory distribution of this nerve often overlaps with the medial brachial cutaneous nerve, emphasizing its critical contributions to the sensation of the upper limb.

The other options are not correct, as they describe areas innervated by different nerves. The lateral arm and shoulder are primarily innervated by the axillary nerve and the radial nerve. The anterior chest wall receives sensory fibers from the thoracic intercostal nerves. The upper back is mainly supplied by the dorsal primary rami of spinal nerves. Hence, these distinctions clarify why the intercostobrachial nerve is specifically associated with the sensory supply to the medial arm and axilla.