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

Which muscle is innervated by the musculocutaneous nerve?

1. Biceps brachii

2. Deltoid

3. Triceps brachii

4. Flexor carpi ulnaris

The correct answer is: Biceps brachii

The biceps brachii is innervated by the musculocutaneous nerve, which arises from the brachial plexus. This nerve specifically innervates muscles in the anterior compartment of the arm. The biceps brachii is primarily responsible for flexion of the elbow and supination of the forearm. Its dual role in both elbow flexion and forearm supination is critical in various functional movements, such as lifting and pulling. Other choices include muscles that are innervated by different nerves. The deltoid is innervated primarily by the axillary nerve, which is responsible for shoulder abduction. The triceps brachii, involved in extending the elbow, is innervated by the radial nerve. Lastly, the flexor carpi ulnaris, which aids in wrist flexion and ulnar deviation, is innervated by the ulnar nerve. Each of these muscles has a specific innervation associated with its function and location in the arm, highlighting the importance of understanding neural connections in anatomy and muscle function.