Anato Block II: Arm

Question 1

What are the compartments of the arm?

Answer 1

The anterior compartment, which contains most of the flexor muscles of the elbow/forearm

The posterior compartment, which contains most of the extensor muscles of the elbow/ forearm

Question 2

What are the muscles of the anterior compartment of the arm?

Answer 2

Flexors of the fore arm
1. Biceps brachii
2. Coracobrachialis
3. Brachialis

Question 3

Which nerve innervates the muscles of the anterior compartment of the arm?

Answer 3

musculocutaneous nerve (ramification of axillar brachial plexus)

Question 4

What are the muscles of the posterior compartment of the arm?

Answer 4

Extensors of the forearm
1. Triceps brachii
2. Aconeus

Question 5

Which nerve innervates the muscles of the posterior compartment of the arm?

Answer 5

Radial nerve

Question 6

What passes through the quadrangular space?

Answer 6

axillary nerve and posterior circumflex humeral artery passes through here to irrigate posterior part of arm

Question 7

quadrangular space edges:

Answer 7

inferior: teres major
posterior: long head of tricep
anterior: lateral head of tricep
superior: subscapular

Question 8

Proximal attachment of the biceps brachii [origin]

Answer 8

short head: tip of coracoid process of scapula
long head: supraglenoid tubercle of scapula

Question 9

Distal attachment of biceps brachii [insertion]

Answer 9

Tuberosity of radius and fascia of forearm via bicipal aponeurosis

Question 10

Innervation of biceps brachii

Answer 10

musculocutaneous neve (c5, C6, c7)

Question 11

Action of biceps brachii

Answer 11

Supinates forearm and when it is supine flexes fore arm

short head resists dislocation of shoulder

Question 12

Proximal attachment of the coracobrachialis [origin]

Answer 12

Tip of coracoid process of scapula

Question 13

Distal attachment of the coracobrachialis [insertion]

Answer 13

Middle third of media surface of humerus

Question 14

Innervation of coracobrachialis

Answer 14

musculocutaneous neve (c5, C6, c7)

Question 15

Action of coracobrachialis

Answer 15

Helps flex and adduct arm

resists dislocation of shoulder

Question 16

Proximal attachment of the brachialis [origin]

Answer 16

Distal half of anterior surface of humerus

Question 17

Distal attachment of the brachialis [insertion]

Answer 17

Coronoid process and tuberosity of ulna

Question 18

Innervation of brachialis

Answer 18

musculocutaneous neve (c5, c6) and radial nerve (c5, c7)

Question 19

Action of brachialis

Answer 19

Flexes forearm in all positions

Question 20

Proximal attachment of the triceps brachii [origin]

Answer 20

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 21

Distal attachment of the triceps brachii [insertion]

Answer 21

Proximal end of olecranon of ulna and fascia of forearm

Question 22

Innervation of triceps brachii

Answer 22

Radial Nerve (c6, C7, C8)

Question 23

Action of triceps brachii

Answer 23

Chief extensor of forearm

long head resists dislocation of humerus

important for adduction

Question 24

Proximal attachment of the anconeus [origin]

Answer 24

Lateral epicondyle of humerus

Question 25

Distal attachment of the anconeus [insertion]

Answer 25

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

Question 26

Innervation of anconeus

Answer 26

Radial nerve (c7, c8, t1)

Question 27

Action of anconeus

Answer 27

Assists triceps in extending forearm

stabilizes elbow joint

may abduct ulna during pronation