American Board of Surgery Qualifying Exam (ABS QE) Practice Test

What is the primary function of the lateral pectoral nerve?

1. Innervate pectoralis major

2. Provide sensation to the shoulder

3. Innervate intercostal muscles

4. Innervate the serratus anterior

The correct answer is: Innervate pectoralis major

The primary function of the lateral pectoral nerve is to innervate the pectoralis major muscle. The lateral pectoral nerve originates from the lateral cord of the brachial plexus and is primarily responsible for motor innervation to the clavicular head of the pectoralis major. This muscle plays a vital role in movements of the shoulder, such as flexion, adduction, and internal rotation. The nerve's specific targeting of the pectoralis major is significant because this muscle is essential for many upper limb movements and activities. Injury or damage to the lateral pectoral nerve can lead to weakness or atrophy of the pectoralis major, affecting the shoulder's function. The other options pertain to different anatomical structures and functions that do not involve the lateral pectoral nerve directly. For instance, sensation to the shoulder is primarily the role of different nerves, while the intercostal muscles and serratus anterior receive innervation from other branches of the brachial plexus and thoracic nerves.