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 proximal attachment of the trapezius?

Answer 12

Medial third of the superior nuchal line
External occipital protuberance
Nuchal ligament
Spinous processes of C7-T12 vertebrae

Question 13

What is the distal attachment of the trapezius?

Answer 13

Lateral third of clavicle
Acromion
Spine of scapula

Question 14

What is the innervation of the trapezius?

Answer 14

Spinal accessory nerve (CN XI)

C3, C4 spinal fibres

Question 15

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

Answer 15

Motor functions

Question 16

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

Answer 16

Pain reception and proprioception

Question 17

What is the arterial supply of the trapezius?

Answer 17

Transverse cervical artery

Question 18

What is the action of the trapezius?

Answer 18

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 19

What is the most common cause of accessory nerve damage?

Answer 19

Iatrogenic

Question 20

What is meant by iatrogenic?

Answer 20

Due to a medical procedure

Question 21

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

Answer 21

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

Question 22

How is the accessory nerve tested?

Answer 22

Trapezius function can be assessed

Question 23

How can trapezius function be assessed?

Answer 23

By asking the patient to shrug his/her shoulders

Question 24

What are the other clinical features of accessory nerve damage?

Answer 24

Muscle wasting
Partial paralysis of sternocleidomastoid
Asymmetrical neckline

Question 25

Where is the proximal attachment of the latissimus dorsi?

Answer 25

Spinous processes of the inferior 6 thoracic vertebrae (T6-T12)  Thoracolumbar fascia  Iliac crest  Inferior 3 to 5 ribs

Question 26

What happens to the fibres of the latissimus dorsi?

Answer 26

They converge into a tendon

Question 27

What is the distal attachment of the latissimus dorsi?

Answer 27

Floor of intertubercular sulcus of humerus

Question 28

What is the innervation of the latissimus dorsi?

Answer 28

Thoracodorsal nerve (C6-8)

Question 29

What is the arterial supply of the latissimus dorsi?

Answer 29

Thoracodorsal artery

Question 30

What is the action of the latissimus dorsi?

Answer 30

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

Question 31

What are the deep extrinsic muscles of the shoulder?

Answer 31

The levator scapulae  Rhomboid minor  Rhomboid major

Question 32

Where are the deep extrinsic muscles of the shoulder?

Answer 32

In the upper back, under the trapezius

Question 33

What shape is the levator scapulae?

Answer 33

Small, strap-like

Question 34

What is the proximal attachment of the levator scapulae?

Answer 34

Posterior tubercles of the transverse processes of C1-C4 vertebrae

Question 35

What is the distal attachment of the levator scapulae?

Answer 35

Medial border of the scapula superior to the root of the scapular spine

Question 36

What is the innervation of the levator scapulae?

Answer 36

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

Question 37

What is the arterial supply of the levator scapulae?

Answer 37

Transverse cervical artery and ascending cervical artery

Question 38

What is the action of the levator scapulae?

Answer 38

Elevates scapula and rotates its glenoid cavity inferiorly by rotating scapula

Question 39

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

Answer 39

Superiorly

Question 40

What is the proximal attachment of the rhomboid minor?

Answer 40

Nuchal ligament | Spinous processes of C7 and T1 vertebrae

Question 41

What is the distal attachment of the rhomboid minor?

Answer 41

Smooth triangular area at medial end of scapular spine

Question 42

What is the proximal attachment of the rhomboid major?

Answer 42

Spinous processes of T2-T5 vertebrae

Question 43

What is the distal attachment of the rhomboid major?

Answer 43

Medial border of scapula from level of spine to inferior angle

Question 44

What is the innervation of the rhomboid muscles?

Answer 44

Dorsal scapular nerve (C4, C5)

Question 45

What is the action of the rhomboid muscles?

Answer 45

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

Question 46

Draw a diagram illustrating the extrinsic muscle of the shoulder

Answer 46

Answer…