MSK Shoulder

Question 1

There are two groups of shoulder muscles- what are they?

Answer 1

Extrinsic and intrinsic

Question 2

Where do extrinsic muscles originate and insert?

Answer 2

Originate at torso and attach at shoulder bones (scapula, humerus, clavicle)

Question 3

Where do intrinsic muscles originate and insert?

Answer 3

Originate from scapula/clavicle and attach to humerus

Question 4

There are two layers of extrinsic muscles; superficial and deep.
Name the superficial extrinsic muscles.

Answer 4

Trapezius
Latissimus dorsi

Question 5

Innervation of trapezius?

Answer 5

Accessory nerve for motor
Also receives proprioceptor fibres from C3-4 spinal nerve

Question 6

There are a few muscles which are so big that different parts of the muscle have different actions.
These include trapezius and deltoid, which have different types of fibres having different actions.
What are the various actions of the trapezius muscle?

Answer 6

Upper fibres- elevate scapula
Middle fibres- retract scapula
Lower fibres- pull scapula inferiorly

Question 7

What is the innervation of the latissimus dorsi?

Answer 7

Thoracodorsal nerve

Question 8

What is the action of the latissimus dorsi muscle?

Answer 8

Extension, adduction and medial rotation of upper limb

Question 9

Name the deep extrinsic shoulder muscles.

Answer 9

Levator scapulae
Rhomboid major
Rhomboid minor

Question 10

What is the innervation of the deep extrinsic shoulder muscles- the leavtor scapulae and rhomboids?

Answer 10

Dorsal scapular nerve

Question 11

What is the action of the levator scapulae muscle?

Answer 11

Elevation of scapula

Question 12

What is the action of the two rhomboid muscles?

Answer 12

Retraction and rotation of the scapula

Question 13

Which rhomboid muscle sits more superiorly?

Answer 13

Rhomboid minor

Question 14

Where does the rhomboid minor originate from?

Answer 14

Spinous processes of C7-T1

Question 15

Where does the rhomboid major originate from?

Answer 15

Spinous processes of T2-5

Question 16

Name the six intrinsic muscles of the shoulder.

Answer 16

Deltoid
Subscapularis
Infraspinatous
Supraspinatous
Teres major
Teres minor

Question 17

Which of the six intrinsic muscles of the shoulder make up the rotator cuff muscles?

Answer 17

Supraspinatus
Infraspinatus
Teres minor
Subscapularis

Question 18

Innervation of deltoid?

Answer 18

Axillary nerve

Question 19

There are a few muscles which are so big that different parts of the muscle have different actions.
These include trapezius and deltoid, which have different types of fibres having different actions.
What are the various actions of the deltoid muscle?

Answer 19

Anterior fibres- flexion and medial rotation
Middle fibres- abduction
Posterior fibres- extension and lateral rotation

Question 20

Innervation of teres major?

Answer 20

Lower subscapular nerve

Question 21

Action of teres majoe?

Answer 21

Adduction and extension at shoulder

Question 22

Innervation of supraspinatus?

Answer 22

Suprascapular nerve

Question 23

Actions of supraspinatus muscle?

Answer 23

Abduction of upper limb at shoulder

Question 24

Innervation of infraspinatus muscle?

Answer 24

Suprascapular nerve

Question 25

Action of infraspinatus muscle?

Answer 25

Lateral rotation of arm

Question 26

Innervation of subscapularis?

Answer 26

Upper and lower subscapular nerves

Question 27

Action of subscapularis muscle?

Answer 27

Medial rotation of arm

Question 28

Innervation of teres minor?

Answer 28

Axillary nerve

Question 29

Actions of teres minor?

Answer 29

Lateral rotation of arm

Question 30

RECAP- which two intrinsic muscles are innervated by the axillary nerve?

Answer 30

Deltoid
Teres minor