Muscles Of The Superficial Back And Shoulder

Question 1

Trapezius origin and insertion

Answer 1

O: external occipital protuberance, superior nuchal line, ligamentum nuchae (fascia surrounding spinal column), spinous process of C7 to T12
I: acromion process, spine of the scapula, lateral aspect of the clavicle

Question 2

Trapezius innervation and action

Answer 2

Innervation: spinal accessory nerve (cranial nerve IX)
Action: upward scapular rotation, ipsilateral side bending, contralateral rotation of the neck
Upper fibers- elevate the scapula
Lower fibers- depress the scapula
Middle fibers- retract the scapula

Question 3

Latissimus dorsi origin and insertion

Answer 3

O: iliac crest, lower three or four ribs, thoracolumbar fascia, lumbar and sacral vertebrae, inferior angle of the scapula
I: intertubercular groove of the humerus

Question 4

Latissimus dorsi innervation and action

Answer 4

Innervation: thoracodorsal nerve (C5-C7)
Action: shoulder extension, internal rotation, and adduction

Question 5

Rhomboids origin and insertion

Answer 5

O: spinous processes of C7 to T5
I: medial border of the scapula

Question 6

Rhomboids innervation and action

Answer 6

Innervation: dorsal scapular nerve (C5)
Action: scapular retraction and downward rotation

Question 7

Levator scapulae origin and insertion

Answer 7

O: posterior tubercles of the transverse processes of C1 to C4 vertebrae
I: superior angle of the scapula

Question 8

Levator scapulae innervation and action

Answer 8

Innervation: dorsal scapular nerve (C5)
Action: elevates scapulae, downward scapular rotation. Also ipsilateral side bending, and rotation of the neck

Question 9

Deltoid origin and insertion

Answer 9

O: acromion process, spine of the scapula, lateral aspect of the clavicle
I: deltoid tuberosity of the humerus

Question 10

Deltoid innervation and action

Answer 10

Innervation: axillary nerve (C5-C6)
Action: anterior fibers- flex and internally rotate the shoulder
posterior fibers- extend and externally rotate the shoulder
middle fibers- abduct the shoulder
Posterior deltoid - major horizontal abduction

Question 11

Supraspinatus origin and insertion

Answer 11

O: supraspinous fossa of the scapula
I: greater tubercle of the humerus

Question 12

Supraspinatus innervation and action

Answer 12

Innervation: suprascapular nerve (C5-C6)
Action: shoulder abduction

Question 13

Infraspinatus origin and insertion

Answer 13

O: infraspinous fossa of the scapula
I: greater tubercle of the humerus

Question 14

Infraspinatus innervation and action

Answer 14

Innervation: suprascapular nerve (C5-C6)
Action: shoulder external rotation

Question 15

Teres minor origin and insertion

Answer 15

O: lateral border of the scapula
I: greater tubercle of the humerus

Question 16

Teres minor innervation and action

Answer 16

Innervation: axillary nerve (C5-C6)
Action: shoulder external rotation

Question 17

Subscapularis origin and insertion

Answer 17

O: subscapular fossa
I: lesser tubercle of the humerus

Question 18

Subscapularis innervation and action

Answer 18

Innervation: upper and lower subscapular nerve (C6-C8)
Action: shoulder internal rotation

Question 19

Teres major origin and insertion

Answer 19

O: inferior angle of the scapula
I: intertubercular groove of the humerus

Question 20

Teres major innervation and action

Answer 20

Innervation: lower subscapular nerve (C6-C8)
Action: shoulder internal rotation, adduction

Question 21

Rotator cuff

Answer 21

Supraspinatus 
Infraspinatus
Teres minor 
Subscapularis 
Function: to increase dynamic stability of the glenohumeral joint

Question 22

Quadrangular space

Answer 22

Superior border: subscapularis (ant) and the teres minor (post)
Inferior border: teres major
Medial border: long head of the triceps
Lateral border: surgical neck of humerus

Axillary nerve and posterior circumflex humeral artery runs through this space

Question 23

3 branches of the aortic arch

Answer 23

Right brachiocephalic artery
Left subclavian artery
Left common carotid artery

Question 24

Right brachiocephalic division

Answer 24

Right subclavian artery

Right common carotid artery

Question 25

3 parts of the subclavian artery

Answer 25

Part 1 goes from the brachiocephalic artery to the anterior scalene
Part 2 goes behind anterior scalene
Part 3 goes from the anterior scalene to the lateral aspect of the first rib where the vessel changes names and becomes the axillary artery

Question 26

3 parts of the axillary artery

Answer 26

Part 1 goes from the lateral aspect of the first rib to the pectoralis minor
Part 2 goes behind the pectoralis minor
Part 3 goes from the pectoralis minor to the inferior border of the teres major where it changes names again and becomes the brachial artery
The brachial artery will run down into the cubital fossa

Question 27

Axilla borders

Answer 27

Anterior wall: pectoralis major and minor
Posterior wall: subscapularis, latissimus dorsi, and teres major
Medial wall: serratus anterior
Lateral wall: intertubercular groove of he humerus

Question 28

Axilla contents

Answer 28

Axillary artery
Cords of the brachial plexus
SH/LH biceps and coracobrachialis
Long thoracic nerve