Intrinisic Shoudler Muscles

Question 1

Where do the intrinsic muscles of the shoulder originate from?

Answer 1

The scapula and/or clavicle

Question 2

Where do the intrinsic muscles of the shoulder attach to?

Answer 2

The humerus

Question 3

What are the intrinsic muscles of the shoulder?

Answer 3

Deltoid
 Teres major
 Supraspinatus
 Infraspinatus
 Subscapularis
 Teres minor

Question 4

What muscles are considered to be part of the rotator cuff group?

Answer 4

Supraspinatus
Infraspinatus
Subscapularis
Teres minor

Question 5

What shape is the deltoid muscle?

Answer 5

Triangle

Question 6

What can the deltoid muscle be divided into?

Answer 6

Anterior (clavicular), middle (acromial) and posterior (spinal) parts

Question 7

What is the innervation of the deltoid?

Answer 7

Axillary nerve (C5, C6)

Question 8

What is the arterial supply of the deltoid?

Answer 8

Posterior circumflex humeral artery

Question 9

What is the action of the clavicular part of the deltoid?

Answer 9

Flexes and medially rotates arm

Question 10

What is the action of the acromial part of the deltoid?

Answer 10

Abducts arm- takes over from supraspinatus, which abducts the first 15º

Question 11

What is the action of the spinal part of the deltoid?

Answer 11

It extends and laterally rotates the arm

Question 12

What does the teres major form?

Answer 12

The inferior border of the quadrangular space

Question 13

What is the quadrangular space?

Answer 13

The ‘gap’ that the axillary nerve and posterior circumflex humeral artery pass through to reach the posterior scapula region

Question 14

What is the innervation of the teres major?

Answer 14

Lower subscapular nerve (C5, C6)

Question 15

What is the arterial supply of the teres major?

Answer 15

Circumflex scapular artery

Subscapular artery

Question 16

What is the action of the teres major?

Answer 16

Adducts and medially rotates the arm

Question 17

Where do the rotator cuff muscles originate from?

Answer 17

The scapula

Question 18

What do the rotator cuff muscles attach to?

Answer 18

The humeral head

Question 19

What do the rotator cuff muscles collectively do?

Answer 19

The resting tone of these muscles acts to ‘pull’ the humeral head into the glenoid fossa, giving the glenohumeral joint a lot of additional stability

Question 20

What is the innervation of the supraspinatus?

Answer 20

Suprascapular nerve (C4, C5, C6)

Question 21

What is the arterial supply of the supraspinatus?

Answer 21

Suprascapular artery

Question 22

What is the muscle action of the supraspinatous?

Answer 22

Initiates (0-15º) and assists the deltoid (15-90º) in abduction of the arm
Acts with rotator cuff muscles

Question 23

What is the innervation of the infraspinatus?

Answer 23

Suprascapular nerve (C5, C6)

Question 24

What is the arterial supply of the infraspinatus?

Answer 24

Circumflex scapular artery

Suprascapular artery

Question 25

What is the action of the infraspinatus?

Answer 25

Laterally rotates the arm  | Acts with the rotator cuff muscles

Question 26

What is the innervation of the subscapularis?

Answer 26

Upper and lower subscapular nerves (C5, C6, C7)

Question 27

What is the arterial supply of the subscapularis?

Answer 27

Subscapular artery

Question 28

What is the action of the subscapularis?

Answer 28

Medially rotates arm | As part of rotator cuff, helps hold head of humerus in glenoid cavity

Question 29

What is the innervation of the teres minor?

Answer 29

Axillary nerve (C5, C6)

Question 30

What is the arterial supply of the teres minor?

Answer 30

Circumflex scapular artery | Posterior circumflex humeral artery

Question 31

What is the action of the teres minor?

Answer 31

Laterally rotates arm  | Acts with rotator cuff muscles

Question 32

What does rotator cuff tendonitis refer to?

Answer 32

Inflammation of the tendons of the rotator cuff muscles

Question 33

What does rotator cuff tendonitis occur due to?

Answer 33

Secondary to repetitive use of the shoulder joint

Question 34

What is the muscle most commonly affected in rotator cuff tendonitis?

Answer 34

Supraspinatus

Question 35

Why is the supraspinatus the muscle most commonly affected in rotator cuff tendonitis?

Answer 35

During abduction, it ‘rubs’ against the coraco-acromial arch, which over time causes inflammation and degenerative changes in the tendon itself

Question 36

What does treatment of rotator cuff tendonitis involve?

Answer 36

Conservative treatment includes rest, analgesia and physiotherapy In more servere cases, steroid injections and surgery can be considered