Muscles of the Shoulder Joint

Question 1

Where are the Origins of the Pectoralis Major?

Answer 1

Clavicle, sternum and cartilage of ribs 1-6

Question 2

Where is the Insertion of the Pectoralis Major?

Answer 2

Humerus

Question 3

What joint does the Pectoralis Major cross?

Answer 3

Glenohumeral/Shoulder Joint

Question 4

What are the Actions of the Pectoralis Major?

Answer 4

Shoulder horizontal flexion, shoulder adduction, shoulder medial rotation

Question 5

Where is the Origin of the Teres Major?

Answer 5

Lateral border of the scapula near the inferior angle

Question 6

Where is the Insertion of the Teres Major?

Answer 6

Humerus (proximal, anterior)

Question 7

What joint does the Teres Major cross?

Answer 7

Shoulder

Question 8

What are the Actions of the Teres Major?

Answer 8

Medial rotation, adduction and extension of the shoulder joint

Question 9

Where are the Origins of the Latissimus Dorsi?

Answer 9

Via the thoracolumbar fascia (TLF) from spinous processes of T6–T12, lumbar and sacral vertebrae and iliac crest. Also the lower 3–4 ribs and bottom (inferior) edge of the scapula

Question 10

What is the TLF?

Answer 10

TLF is a sheet of ligamentous connective tissue covering the lumbar spine and Sacro-Iliac joint. It is primarily made of collagen so has no contractile properties.

Question 11

Where is the Insertion of the Latissimus Dorsi?

Answer 11

Top of the Humerus

Question 12

What joint does the Latissimus Dorsi cross?

Answer 12

Shoulder Joint

Question 13

What are the Actions of the Latissimus Dorsi when the Origin is fixed?

Answer 13

Adducts and extends the arm. Assists in medial rotation of the arm. Depresses the shoulder girdle via the insertion on the humerus

Question 14

What is the Action of the Latissimus Dorsi when the Insertion is fixed?

Answer 14

Tilts the pelvis forwards

Question 15

Where is the Origin of the anterior head of the Deltoid?

Answer 15

Clavicle

Question 16

Where is the Origin of the medial head of the Deltoid?

Answer 16

Acromion process of the scapula

Question 17

Where is the Origin of the posterior head of the Deltoid?

Answer 17

Spine of the scapula

Question 18

Where is the Insertion of the Deltoid?

Answer 18

Lateral surface of the humerus (nearly halfway round)

Question 19

What joint does the Deltoid cross?

Answer 19

Shoulder

Question 20

What are the Actions of the Anterior fibres of the Deltoid?

Answer 20

Shoulder flexion and assist in horizontal flexion and medial rotation

Question 21

Which Deltoid fibres abduct the shoulder?

Answer 21

All, but emphasis on medial

Question 22

What are the Actions of the Posterior fibres of the Deltoid?

Answer 22

Shoulder extension and assist in lateral flexion and horizontal flexion