Untitled Quiz

Questions and Answers

What is the function of the trapezius muscle?

Enables you to shrug your shoulders and extend your head (correct)

Prime mover of back extension

Adducts the shoulder

Rotates humerous laterally

What does the latissimus dorsi muscle do?

Adducts the shoulder and causes extension of shoulder joint

The deltoid is the antagonist of the latissimus dorsi.

True

What is the prime mover of back extension?

Erector spinae Signup and view all the answers

What is the function of the quadratus lumborum?

Helps maintain upright posture Signup and view all the answers

What action do the rhomboids perform?

Rotate the glenoid cavity of the scapulae inferiorly Signup and view all the answers

What is the synergist of the trapezius in scapular elevation?

Levator scapulae Signup and view all the answers

What is the function of the teres major?

Synergist of latissimus dorsi in extension and adduction of the humerus Signup and view all the answers

What muscle prevents downward dislocation of the humerus?

Supraspinatus Signup and view all the answers

What does the infraspinatus muscle do?

Rotates humerus laterally Signup and view all the answers

What muscle lies immediately inferior to the infraspinatus?

Teres minor Signup and view all the answers

What is the function of the serratus anterior?

Holds scapula tightly against thorax wall Signup and view all the answers

Study Notes

Posterior Trunk Muscles

Trapezius: Key muscle for shoulder shrugging and head extension. It elevates, stabilizes, and depresses the scapulae.
Latissimus Dorsi: Facilitates shoulder adduction and extension of the shoulder joint; important for upper body movements.
Deltoid: Functions as an antagonist to latissimus dorsi, primarily involved in shoulder abduction and arm movements.
Erector Spinae: A crucial muscle group for back extension, composed of three columns that maintain posture and assist in standing.
Quadratus Lumborum: Contributes to the posterior abdominal wall structure, helping maintain upright posture and stabilize the pelvis.
Rhomboids: Responsible for the inferior rotation of the scapula's glenoid cavity and retracting the scapulae, they help square the shoulders.
Levator Scapulae: Works alongside the trapezius to elevate the scapula and can flex the head to the same side.
Teres Major: Acts as a synergistic muscle with the latissimus dorsi to assist in the extension and adduction of the humerus.
Supraspinatus: A rotator cuff muscle that plays a protective role by preventing downward dislocation of the humerus.
Infraspinatus: Another rotator cuff muscle, responsible for laterally rotating the humerus and stabilizing the shoulder joint.
Teres Minor: This rotator cuff muscle is located just below the infraspinatus and assists in lateral rotation of the humerus.
Serratus Anterior: Keeps the scapula pressed against the thoracic wall, essential for shoulder movements and stability.