The arm muscle that both flexes and supinates the forearm is the a. brachialis, b. brachioradialis, c. biceps brachii, d. triceps brachii.

Verified step by step guidance

1. Identify the primary actions of each muscle listed in the options.
2. Understand that flexion of the forearm involves decreasing the angle between the forearm and the upper arm.
3. Recognize that supination of the forearm involves rotating the forearm so the palm faces upwards.
4. Recall that the biceps brachii is known for its role in both flexing the forearm and supinating the forearm.
5. Conclude that the muscle which both flexes and supinates the forearm is the biceps brachii.

Key Concepts

Muscle Functions

Muscles can perform various functions, primarily categorized as flexion, extension, supination, and pronation. Flexion refers to decreasing the angle between body parts, while supination involves rotating the forearm so the palm faces upward. Understanding these functions is crucial for identifying which muscle performs specific movements.

Biceps Brachii

The biceps brachii is a prominent muscle located in the upper arm, known for its role in flexing the elbow and supinating the forearm. It has two heads (long and short) that originate from different points on the shoulder and converge to insert on the radius bone of the forearm. This dual functionality makes it a key muscle in arm movements.

Muscle Anatomy

Understanding muscle anatomy involves knowing the location, origin, insertion, and action of muscles. The brachialis, brachioradialis, and triceps brachii are also important muscles in the arm, but they have distinct functions. Familiarity with these anatomical details helps in accurately identifying which muscle is responsible for specific movements.