1. The arm

Question 1

Name the muscles of the anterior compartment of the arm.

Answer 1

1. biceps brachii
2. brachialis
3. coracobrachialis

Question 2

which nerve supplies the muscles of the anterior arm?

Answer 2

musculocutaneous n. (C5-7)

Question 3

describe the attachments of biceps brachii.

Answer 3

origin:

• supraglenoid tubercle of scapula (long head)
• coracoid process (short head)

insertion:

• radial tuberosity
• forearm fascia via bicipital aponeurosis

Question 4

what are the functions of biceps brachii?

Answer 4

1. forarm supination (main)
2. elbow flexion (when supinated)
3. some shoulder flexion

Question 5

which spinal cord segment does biceps tendon reflex test?

Answer 5

C6

Question 6

Describe the effects of biceps tendon rupture.

Answer 6

• Popeye sign: characteristic bulge where muscle belly is on elbow flexion
• little weakness due to action of brachialis and supinator

Question 7

describe the attachment of brachialis

Answer 7

• origin: anterior surface of humeral shaft

- insertion: ulna tuberosity

Question 8

what is the function of brachialis?

Answer 8

• elbow flexion

Question 9

describe the attachments of coracobrachialis

Answer 9

• origin: coracoid process

- insertion: medial surface of humeral shaft (middle 1/3)

Question 10

what are the functions of coracobrachialis?

Answer 10

1. shoulder flexion

2. weak arm adduction

Question 11

name the muscles of the posterior arm compartment.

Answer 11

only triceps brachii

Question 12

which nerve supplies triceps brachii?

Answer 12

radial nerve (C5-T1)

Question 13

describe the attachments of triceps brachii.

Answer 13

origin:

• 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)

insertion: olecranon of ulna

Question 14

what is the function of triceps brachii?

Answer 14

elbow extension

Question 15

which muscle assists triceps brachii in elbow extension? what are the attachments of this muscle?

Answer 15

anconeus

• origin: lateral epicondyle of humerus
• insertion: lateral surface of olecranon

Question 16

describe the arterial supply to the arm.

Answer 16

• Brachial artery provides main arterial supply: descends down arm posterior to median n.
• Brachial artery gives rise to profunda brachii immediately distal to teres major. Travels along posterior surface of humerus, running in radial groove. Supplies posterior arm muscles.

Question 17

Describe the venous drainage of the arm.

Answer 17

• Paired deep veins - brachial vein - accompany brachial artery, ends by merging with basilic vein to form axillary vein.
• 2 superficial veins: cephalic and basilic veins

Question 18

which nerves run through the arm?

Answer 18

1. radial
2. musculocutaneous
3. median
4. ulnar