Which action is primarily produced by the biceps brachii muscle?

• A. Abduction of the shoulder
• B. Flexion of the wrist and fingers
• C. Flexion of the elbow and supination of the forearm
• D. Extension of the elbow

Answer: (C)

Verified step by step guidance

1. Step 1: Identify the anatomical location and attachments of the biceps brachii muscle. It originates from the scapula and inserts on the radius bone of the forearm.
2. Step 2: Understand the primary movements produced by the biceps brachii. Since it crosses the elbow joint anteriorly, it mainly acts to flex the elbow.
3. Step 3: Recognize that the biceps brachii also attaches to the radius, which allows it to perform supination of the forearm (rotating the palm upward).
4. Step 4: Differentiate these actions from other movements such as abduction of the shoulder (which involves muscles like the deltoid) and wrist/finger flexion (which involves forearm muscles like the flexor digitorum).
5. Step 5: Conclude that the primary actions of the biceps brachii are flexion of the elbow and supination of the forearm, based on its anatomical position and function.