2.3.5. ANATOMY LAB Friday: Arm

Question 1

What innervates the biceps brachii?

Answer 1

Musculocutanous nerve (C5 & C6)

Question 2

Origins of the two heads of the biceps?

Answer 2

Short head: tip of coracoid process of scapula

Long head: supraglenoid tubercle of scapula

Question 3

Insertions of the biceps?

Answer 3

Tuberosity of the radius and fascia of forearm via bicipital aponeurosis

Question 4

Action of the biceps?

Answer 4

Supinates forearm, and when it is supine, flexes forearm

Question 5

Origin of the brachialis muscle?

Answer 5

Distal half of the anterior surface of the humerus

Question 6

Insertion of the brachialis muscle?

Answer 6

coronoid process and tuberosity of the ulna

Question 7

Action of the brachialis

Answer 7

Major flexor of the forearm, flexes forearm in all positions

Question 8

What three muscles does the musculocutaneous nerve innervate?

Answer 8

Biceps brachii, Brachialis, Coracobrachialis

Question 9

Origin of the coracobrachialis muscle?

Answer 9

Tip of coracoid process of scapula

Question 10

Insertion of the coracobrachialis muscle?

Answer 10

Middle third of medial surface of humerus

Question 11

Action of the coracobrachialis muscle?

Answer 11

Helps to flex and adduct the arm

Question 12

The triceps muscle is innervated by?

Answer 12

the radial nerve (C6, C7, C8)

Question 13

Origins of the triceps?

Answer 13

Long head: infraglenoid tubercle of scapula
Lateral head: posterior surface of humerus, superior to radial groove
Medial head: posterior surface of humerus, inferior to radial groove

Question 14

Insertions of triceps?

Answer 14

Proximal end of olecranon process of the ulna and fascia of the forearm

Question 15

Action of the triceps?

Answer 15

Chief extensor of forearm; long head steadies head of abducted humerus

Question 16

The anconeus muscle is innervated by?

Answer 16

Radial nerve (C7, C8, T1)

Question 17

What TWO nerves innervate the Brachialis?

Answer 17

Musculocutaneous nerve (C5&6)
Radial nerve (C5&C7)

Question 18

What innervates the Coracobrachialis?

Answer 18

Musculocutaneous nerve (C5, C6, C7)

Question 19

Origin of the anconeus?

Answer 19

lateral epichondyle of humerus

Question 20

Insertion of the anconeus?

Answer 20

Lateral surface of olecranon and superior part of posterior surface of the ulna

Question 21

Action of the anconeus?

Answer 21

Assists triceps in extending forearm; stabilizes elbow joint; abducts ulna

Question 22

Explain the origin and route of the musculocutaneous nerve.

Answer 22

Begins opposite the inferior border of the pectoralis minor, pierces the coracobrachialis, and continues distally between the biceps and the brachialis. After supplying all 3 muscles of the anterior compartment of the arm, the nerve emerges lateral to the biceps as the lateral cutaneous nerve of the forearm.

Question 23

What is another name for the profunda brachii artery?

Answer 23

Deep brachial artery

Question 24

What group of muscles does the radial nerve supply?

Answer 24

All the muscles in the posterior compartment of the arm (and forearm)

Question 25

Explain the route of the median nerve in the arm

Answer 25

Runs distally in the arm on the lateral side of the brachial artery until it reaches the middle of the arm, where is crosses to the medial side and contacts the brachialis. The median nerve then descends into the cubital fossa, where it lies deep to the bicipital aponeurosis and median cubital vein.

Question 26

The ______ nerves have no branches in the arm, but do supply articular branches to the elbow joint.

Answer 26

median & ulnar