Pre-Lab: Shoulder and Arm 2

Question 1

What is the anterior rotator cuff muscle?

Answer 1

Subscapularis

Question 2

Where does the anterior rotator cuff muscle originate, insert and what is its action?

Answer 2

O = Subscapular fossa

I = Lesser tuberosity of the humerus

A = Medial rotation of the arm

Question 3

What muscles medially rotate the humerus?

Answer 3

Subscapularis

Latissimus dorsi

Pec major

Question 4

What are the posterior rotator cuff muscles?

Answer 4

Supraspinatous

Infraspinatous

Teres major

Teres minor

Question 5

What is the origin, insertion, and action of supraspinatous?

Answer 5

O = Supraspinous fossa of scapula

I = Greater tuberosity of the humerus

A = Abducts the arm (tendon goes above the joint capsule)

Question 6

What is the origin, insertion, and action of infraspinatous?

Answer 6

O = Infraspinous fossa of scapula

I = Greater tuberosity of the humerus

A = Lateral rotation of the arm

Question 7

What is the origin, insertion, and action of teres minor?

Answer 7

O = Posterior surface of the scapula near the lateral border

I = Greater tuberosity of the humerus

A= Lateral rotation and adduction of the arm.

Question 8

What is the origin, insertion, and action of teres major?

Answer 8

O = Posterior surface of the scapula

I = Bicipital groove of the humerus

A = Adduction, extension, and medial rotation of the arm (assists lat dorsi)

Question 9

What is the anatomical significance of teres major?

Answer 9

An artery that passes this point changes its name.

Question 10

What do the rotator cuff muscles do?

Answer 10

They stabilise the head of the humerus in the glenoid fossa

Question 11

What are the heads of the biceps brachii called?

Answer 11

Short head

Long head

Question 12

Where does biceps brachii originate and insert and what is its action?

Answer 12

O = Long head: Supraglenoid tubercle of the glenoid fossa. (supraglenoid tubercle)

Short head: Coracoid process of scapula

I = Bicipital tubercle of radius and bicipital aponeurosis

A = Flex arm; flex and supinate forearm

Question 13

Which bicep head is more lateral?

Answer 13

The long head

Question 14

Where does brachialis originate and insert?

Answer 14

O = Distal half of humeral shaft

I = Ulna tubercle of the ulna

A = flexes forearm

Question 15

What is the origin, insertion, and action of triceps brachii?

Answer 15

O =
Long head: Infraglenoid tubercle of scapula

Lateral and medial head: Shaft of humerus

I = Olecranon process of the ulna

A = Extends forearm
Long head adducts the arm)

Question 16

What are the anterior compartment muscles of the arm?

Answer 16

Biceps Brachii

Brachialis

Question 17

What is the origin, insertion, and action of anconeus?

Answer 17

O = Lateral epicondyle of the humerus

I = Olecranon process of ulna (lateral)

A = Extends the forearm

Question 18

What part of the spinal cord gives rise to the roots that innervate the shoulders and upper limb muscles?

Answer 18

The cervical enlargement

Question 19

How are the radial and axillary nerves formed in the brachial plexus?

Answer 19

The posterior divisions of all trunks come together to form a posterior cord which divides into radial and axillary nerves.

Question 20

How are the musculocutaneous, ulnar and median nerves formed?

Answer 20

Anterior divisions of Upper and Middle trunks form lateral cord which divides into musculocutaneous and median nerves

The medial cord gets the anterior branches from the anterior division of the lower trunk and then combines with the median nerve. This medial cord also forms the ulnar nerve.

Question 21

What structures are innervated by the musculocutaneous nerve?

Answer 21

Flexors of the forearm (biceps brachii, and brachialis)

Coracobrachialis

Question 22

What does the median nerve innervate?

Answer 22

Supplies muscles in forearm and hand

Question 23

What does the axillary nerve innervate?

Answer 23

Teres minor and deltoids

Question 24

What does the radial nerve innervate?

Answer 24

Triceps brachii

Extensor muscles of the forearm

Question 25

What arteries supply the muscles of the upper limb?

Answer 25

Brachiocephalic trunk (left side of the arch of the aorta) forms common carotid and subclavian arteries.

Subclavian forms the internal thoracic artery and axillary artery (just after the point under the clavicle) as well as the vertebral artery

Axillary artery becomes the brachial artery at the teres major muscle.

Brachial artery divides into profunda brachial artery and the ulnar collateral artery

Profunda brachial artery travels posteriorly and supplies posterior arm. Ulnar collateral artery goes behind medial epicondyle and forms an anastomoses anteriorly in the forearm.

Question 26

What branches off the axillary artery?

Answer 26

The subscapular artery

Humeral circumflex artery

Question 27

What veins provide superficial return?

Answer 27

Basilic and cephalic veins

Question 28

What veins provide deep return?

Answer 28

Brachial vein

Axillary vein

Subclavian vein -> External jugular vein

Internal jugular vein

Brachiocephalic vein

Superior Vena cava

Names of deep return follow the arteries.

Question 29

Where does the basilic vein drop its blood?

Answer 29

In the brachial vein

Question 30

Where does the cephalic vein drop its blood?

Answer 30

In the axillary vein just before the clavicle

Question 31

Where are the cephalic and basilic vein connected?

Answer 31

in the cubital fossa (at the median cubital vein)