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

Which cervical roots contribute to the musculocutaneous nerve?

1. C5, C6, C7

2. C5, C6

3. C8, T1

4. C5, C7, T1

The correct answer is: C5, C6, C7

The musculocutaneous nerve primarily arises from the upper trunk of the brachial plexus, specifically formed by contributions from the fifth, sixth, and seventh cervical roots. These roots combine to form the musculocutaneous nerve, which innervates specific muscles of the upper arm, including the biceps brachii, brachialis, and coracobrachialis. Each of these cervical roots plays a critical role in providing the necessary motor function to support these muscles. C5 contributes to the initiation of upper extremity movements and shoulder stabilization, while C6 and C7 enhance the functionality necessary for elbow flexion and forearm supination through their innervation of the biceps brachii and brachialis muscles. Collectively, these roots' contributions allow for effective movement and coordination of the arm. Other options involve combinations of roots that are either incomplete or do not correspond with the anatomical and functional structure of the musculocutaneous nerve. Rather than the correct triad, recognizing the specific cervical roots that contribute is essential for accurate understanding and application in clinical settings related to musculocutaneous nerve function.