Extrinsic Muscles of the Shoudler

Question 1

What are the muscles of the shoulder associated with?

Answer 1

Movements of the upper limb

Question 2

What do the muscles of the shoulder produce?

Answer 2

The characteristic shape of the shoulder

Question 3

What can the muscles of the shoulder be divided into?

Answer 3

Extrinsic

Intrinsic

Question 4

What are the extrinsic muscles of the shoulder?

Answer 4

Those that originate from the torso, and attach to the bones of the shoulder (clavicle, scapula or humerus)

Question 5

What are the intrinsic muscles of the shoulder?

Answer 5

Those that originate form the scapula and/or clavicle, and attach to the humerus

Question 6

Where are the extrinsic shoulder muscles located?

Answer 6

In the back

Question 7

What are the extrinsic shoulder muscles organised into?

Answer 7

A superficial and deep layer

Question 8

What are the superficial extrinsic shoulder muscles?

Answer 8

Trapezius

Latissimus dorsi

Question 9

What is the most superficial of all the back muscles?

Answer 9

The trapezius

Question 10

What shape is the trapezius?

Answer 10

Broad, flat, triangular

Question 11

What do the muscles on each side of the trapezius form?

Answer 11

A trapezoid shape

Question 12

What is the innervation of the trapezius?

Answer 12

Spinal accessory nerve (CN XI)

C3, C4 spinal fibres

Question 13

What is the function of the spinal accessory nerve on the trapezius?

Answer 13

Motor functions

Question 14

What is the function of the C3 and C4 spinal nerves on the trapezius?

Answer 14

Pain reception and proprioception

Question 15

What is the arterial supply of the trapezius?

Answer 15

Transverse cervical artery

Question 16

What is the action of the trapezius?

Answer 16

Descending part elevates and rotates during abduction of arm
Ascending part depresses
Middle part (or all parts together) retracts scapula
Descending and ascending parts together rotate glenoid cavity superiorly

Question 17

What is the most common cause of accessory nerve damage?

Answer 17

Iatrogenic

Question 18

What is meant by iatrogenic?

Answer 18

Due to a medical procedure

Question 19

What medical procedure in particular can cause trauma to the accessory nerve?

Answer 19

Operations such as cervical lymph node biopsy or cannulation of the internal jugular vein

Question 20

How is the accessory nerve tested?

Answer 20

Trapezius function can be assessed

Question 21

How can trapezius function be assessed?

Answer 21

By asking the patient to shrug his/her shoulders

Question 22

What are the other clinical features of accessory nerve damage?

Answer 22

Muscle wasting
Partial paralysis of sternocleidomastoid
Asymmetrical neckline

Question 23

What happens to the fibres of the latissimus dorsi?

Answer 23

They converge into a tendon

Question 24

What is the innervation of the latissimus dorsi?

Answer 24

Thoracodorsal nerve (C6-8)

Question 25

What is the arterial supply of the latissimus dorsi?

Answer 25

Thoracodorsal artery

Question 26

What is the action of the latissimus dorsi?

Answer 26

Extends, adducts, and medially rotates the humerus  | Raises body towards arm during climbing

Question 27

What are the deep extrinsic muscles of the shoulder?

Answer 27

The levator scapulae  Rhomboid minor  Rhomboid major

Question 28

Where are the deep extrinsic muscles of the shoulder?

Answer 28

In the upper back, under the trapezius

Question 29

What shape is the levator scapulae?

Answer 29

Small, strap-like

Question 30

What is the innervation of the levator scapulae?

Answer 30

``` Dorsal scapular nerve (C4, C5) Cervical nerve (C3, C4) ```

Question 31

What is the arterial supply of the levator scapulae?

Answer 31

Transverse cervical artery and ascending cervical artery

Question 32

What is the action of the levator scapulae?

Answer 32

Elevates scapula and rotates its glenoid cavity inferiorly by rotating scapula

Question 33

Where is the rhomboid minor situated relative to the rhomboid major?

Answer 33

Superiorly

Question 34

What is the innervation of the rhomboid muscles?

Answer 34

Dorsal scapular nerve (C4, C5)

Question 35

What is the action of the rhomboid muscles?

Answer 35

Retract scapula and rotate its glenoid cavity inferiorly | Fix scapula to thoracic wall

Question 36

Draw a diagram illustrating the extrinsic muscle of the shoulder

Answer 36

Answer…