Muscles Of Shoulder

Question 1

What are the rotator cuff muscles?

Answer 1

Subscapularis
Supraspinatus
Infraspinatus
Teres minor

Question 2

Origin and insertion of deltoid?

Answer 2

Origin: lateral 1/3 of clavicle (anterior head), acromion (middle), and spine of scap (posterior head)
Insertion: deltoid tuberosity on humerus

Question 3

What innervates deltoid muscle?

Answer 3

Axillary nerve.

Question 4

Actions of deltoid muscle?

Answer 4

Abduction after first 15 degrees.
Anterior head flexes and medially rotates humerus.
Posterior head extends and laterally rotates humerus.

Question 5

Origin and insertion of subscap?

Answer 5

Origin: subscap fossa
Insertion: lesser tubercle of humerus

Question 6

Innervation of subscap?

Answer 6

Upper and lower subscapuluar nerve

Question 7

Actions of subscap?

Answer 7

Medial rotation of humerus.

Question 8

Origin and insertion of supraspinatus?

Answer 8

Origin: supraspinous fossa
Insertion: superior facet of greater tubercle

Question 9

Innervation of supraspinatus?

Answer 9

Suprascapular nerve

Question 10

Action of supraspinatus?

Answer 10

Initiates abduction of humerus at glenohumeral joint.
Laterally rotates the humerus when decelerating the arm in throwing motion.

Question 11

Origin and insertion of infraspinatus?

Answer 11

Origin: infraspinous fossa
Insertion: middle facet of greater tubercle

Question 12

Innervation of intraspinatous?

Answer 12

Suprascapular nerve

Question 13

Action of infraspinatus?

Answer 13

Lateral rotation of humerus

Question 14

Origin and insertion of teres minor?

Answer 14

Origin: upper part of lateral border of scap
Insertion: inferior facet of greater tubercle

Question 15

Innervation of teres minor?

Answer 15

Axillary nerve

Question 16

Action of teres minor?

Answer 16

Lateral rotation of humerus.

Question 17

Origin and insertion of teres major?

Answer 17

Origin: lower lateral border and inferior angle of scap
Insertion: medial lip of intertubucercular groove

Question 18

Innervation of teres major?

Answer 18

Lower subscapular nerve

Question 19

Action of teres major?

Answer 19

Adducts and medially rotates the humerus

Question 20

What exists in triangular space?

Answer 20

Circumflex scapular artery

Question 21

What exists in quadrangular space?

Answer 21

Axillary nerve and posterior humeral circumflex artery

Question 22

What does the triangular interval consist of?

Answer 22

Radial nerve, profunda brachii artery

Question 23

What are entrapment sites for Suprascapular nerve (C4/5/6)?

Answer 23

Suprascapular notch and spinoglenoid notch

Question 24

What are entrapment sites for Axillary nerve (C5/6)?

Answer 24

Ventrolateral scapula and quadrangular space