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

Which nerves innervate the pectoralis major and pectoralis minor?

1. Medial pectoral nerve

2. Lateral pectoral nerve

3. Thoracodorsal nerve

4. Suprascapular nerve

The correct answer is: Medial pectoral nerve

The pectoralis major and pectoralis minor muscles receive their innervation primarily from the medial pectoral nerve, which branches from the brachial plexus. The medial pectoral nerve specifically innervates the pectoralis minor muscle and also sends branches to the pectoralis major, highlighting its crucial role in motor control of these chest muscles. Understanding the anatomical pathways is essential. The pectoralis major is responsible for arm movements such as adduction and medial rotation, while the pectoralis minor plays a role in stabilizing the scapula and assisting with shoulder movements. Given their close anatomical relationship, the medial pectoral nerve's innervation provides precise control and coordination of actions involving these muscles. While the lateral pectoral nerve does contribute to the innervation of the pectoralis major, the question specifically seeks to identify the innervation of both muscles, for which the medial pectoral nerve is the primary nerve responsible. The thoracodorsal nerve primarily innervates the latissimus dorsi muscle and does not significantly innervate the pectoralis muscles. The suprascapular nerve is involved in innervating shoulder muscles such as the supraspinatus and infraspinatus