Question

Which muscle performs shoulder flexion?

A. Anterior deltoid
B. Infraspinatus
C. Middle deltoid
D. Supraspinatus

Answer 1

The anterior deltoid muscle performs shoulder flexion, and the triceps brachii is responsible for extending the forearm.

Step-by-step explanation:

The muscle responsible for shoulder flexion is the anterior deltoid. This muscle is part of the deltoid group which is the major abductor of the arm and is involved in several other movements including flexing and medial rotation of the shoulder, as well as extension and lateral rotation. Therefore, the correct answer to the question, which muscle performs shoulder flexion, is A. Anterior deltoid.

Regarding the muscle that extends the forearm, the triceps brachii is the principal muscle responsible for this action. It is not involved in flexion of the arm, which is mainly performed by the biceps brachii along with the brachialis and the coracobrachialis. Therefore, the correct answer to the latter question is B. triceps brachii.

Answer 2

The anterior portion of the deltoid muscle is primarily responsible for shoulder flexion, a movement where the arm is lifted forward and up in front of the body. This should not be confused with the roles of the infraspinatus, middle deltoid, and supraspinatus, which are involved in other shoulder movements. The correct option for the muscle performing shoulder flexion is A. Anterior deltoid.

Step-by-step explanation:

The muscle that performs shoulder flexion is a significant element in understanding human anatomy, particularly during movements that involve the arms. The shoulder is a complex joint that is capable of a wide range of motions, thanks in part to the muscles that surround it. Shoulder flexion, which is the action of lifting the arm forward and up in front of the body, is one movement that is integral to many activities of daily living and sports. Among the muscles that contribute to shoulder flexion, the deltoid muscle is noteworthy. Specifically, the anterior deltoid is the portion of the deltoid muscle that is primarily responsible for flexing the shoulder. The anterior deltoid is part of a musculature that includes the rotator cuff, whose tendons provide additional stability to the shoulder joint.

Considering the options provided in the question:

• Anterior deltoid - The muscle that assists with shoulder flexion, as well as medial rotation and abduction of the arm.

• Infraspinatus - A rotator cuff muscle that primarily helps with lateral rotation of the arm, and is not directly associated with shoulder flexion.

• Middle deltoid - This region of the deltoid muscle is chiefly involved in the abduction of the arm.

• Supraspinatus - Also part of the rotator cuff, its main role is in the abduction of the arm.

The correct option in the final part of the answer, regarding which muscle performs shoulder flexion, is A. Anterior deltoid.