Question

Of all the scapular muscles, the only one that flexes and adducts the arm is the

A) teres major
B) supraspinatus
C) infraspinatus
D) coracobrachialis

Answer 1

The scapular muscle that both flexes and adducts the arm is the coracobrachialis. Among the scapular muscles, it is the only one with this specific combination of movements.

Step-by-step explanation:

The scapular muscle responsible for flexing and adducting the arm is the coracobrachialis. This muscle works by bringing the arm closer to the body (adduction) and moving it forward (flexion). Compared to the other scapular muscles such as the teres major, which assists in adduction and medial rotation, the coracobrachialis is unique as it also flexes the arm.

The teres major extends the arm and assists in adduction and medial rotation but does not flex the arm. The supraspinatus and infraspinatus are involved in abducting and laterally rotating the arm, respectively. Therefore, the correct answer to which scapular muscle flexes and adducts the arm is D) coracobrachialis.

Additionally, regarding the muscles that move the forearm, the muscle that extends the forearm is the triceps brachii. This is distinct from the biceps brachii and brachialis, which are involved in flexing the forearm.