Muscles of the Shoulder

Question 1

Extrinsic muscles originate from the … and attach to …

Answer 1

Torso

Bones (clavicle, scapula, humerus)

Question 2

Intrinsic muscles originate from the … or … and attach to the …

Answer 2

Scapula
Clavicle
Humerus

Question 3

The deltoid muscle can be divided into … parts

Answer 3

3

Anterior, middle, posterior

Question 4

Origin and attachments of deltoid

Answer 4

Originates from lateral third of the clavicle, the acromion and the spine of the scapula
Attaches to deltoid tuberosity on the humerus

Question 5

Action of anterior deltoid fibres

Answer 5

Flexion and medial rotation

Question 6

Action of posterior deltoid fibres

Answer 6

Extension and lateral rotation

Question 7

Action of middle deltoid fibres

Answer 7

Major abductor of the arm

Question 8

Innervation of deltoid

Answer 8

Axillary nerve

Question 9

Origin and attachment of teres major

Answer 9

Originates from the posterior surface of the inferior angle of the scapula
Attaches to the intertubercular groove of the humerus

Question 10

Innervation of teres major

Answer 10

Lower subscapular nerve

Question 11

Action of teres major

Answer 11

Adducts and extends at the shoulder

Medially rotates the arm

Question 12

Name the 4 rotator cuff muscles

Answer 12

Supraspinatus, subscapularis, infraspinatus, teres minor

Question 13

Origin and attachment of supraspinatus

Answer 13

Originates from the supraspinous fossa of the scapula

Attaches to the greater tubercle of the humerus

Question 14

Innervation of supraspinatus

Answer 14

Suprascapular nerve

Question 15

Action of supraspinatus

Answer 15

Abducts the arm up to 15 degrees and assists deltoid between 15 and 90 degrees

Question 16

Origin and attachment of infraspinatus

Answer 16

Originates from infraspinous fossa of the scapula

Attaches to the greater tubercle of the humerus

Question 17

Innervation of infraspinatus

Answer 17

Suprascapular nerve

Question 18

Action of infraspinatus

Answer 18

Laterally rotates the arm

Question 19

Origin and attachment of subscapularis

Answer 19

Originates from subscapular fossa on the costal surface of the sacpula
Attaches to the lesser tubercle of the humerus

Question 20

Innervation of subscapularis

Answer 20

Upper and lower subscapular nerves

Question 21

Action of subscapularis

Answer 21

Medially rotates the arm

Question 22

Origin and attachments of teres minor

Answer 22

Originates from posterior surface of the scapula

Attaches to greater tubercle of the humerus

Question 23

Innervation of teres minor

Answer 23

Axillary nerve

Question 24

Action of teres minor

Answer 24

Laterally rotates the arm