Shoulder muscles

Question 1

What is the main function of the deltoids?

Answer 1

Any movement of the scapula must include the deltoids, the deltoids is an antagonist muscle of itself, the anterior fibers flexes and internally rotate the humerus while the posterior muscles laterally rotates and extends the humerus

Question 2

What is the function of the teres major

Answer 2

Internally rotates the humerus, only effective when rhomboids stabilises the scapula.

Question 3

What is the function of the coracobrachialis?

Answer 3

It is used to flex and adduct the humerus.

Question 4

What is the function of the latissimus dorsi?

Answer 4

It is a powerful extensor of the humerus, it adducts and internally rotates the humerus, can also laterally flex the spine and anteriorly tilt the pelvis.

Question 5

What is the function of the pectoralis major?

Answer 5

it works together with the latissimus dorsi to adduct the humerus from raised abducted position. It also internally rotates the humerus, and extends and flexes the shoulder.