Anatomy -- Upper Limb 3

Question 1

Describe the possible movements of the arm at the elbow joint

Answer 1

• Flexion
• Extension
• Pronation
• Supination

Question 2

Define compartment syndrome

Answer 2

Any swelling (following trauma) in a compartment leading to increased pressure, which presses on the muscles, blood vessels and nerves.

If pressure is high enough, blood flow to the compartment will be blocked, and if it’s long enough, the muscles may die

Question 3

2 compartments of arm muscles and the nerves that innervate them

Answer 3

• Posterior/extensor compartment (radial nerve)
• Anterior/flexor compartment (musculocutaneous nerve)

Question 4

Exception to the function of the arm muscle compartments

Answer 4

Barchioradialis muscle originates from posterior compartment and is innervated by radial nerve, but it is involved in flexion of the forearm

Question 5

3 muscles of the anterior arm compartment

Answer 5

• Coracobrachialis muscle
• Biceps brachii muscle
• Brachialis muscle

Question 6

Function of biceps brachii muscle

Answer 6

Supination, flexion of forearm

Flexion of arm

Question 7

Function of coracobrachialis muscle

Answer 7

Flexion and adduction of arm

Question 8

Function of brachialis muscle

Answer 8

Flexion of forearm

Question 9

Only muscle of the posterior arm compartment

Answer 9

Triceps muscle

Question 10

Functions of triceps muscle

Answer 10

Extension of forearm and arm

Adduction of arm

Question 11

2 important branches of the axillary/brachial artery

Answer 11

Radial artery

Ulnar artery

Question 12

Vein commonly used for venipuncture in arm

Answer 12

Median cubital vein

Question 13

Vessels connected by arteriovenous fistula for hemodialysis

Answer 13

Cephalic vein and radial artery

Question 14

What does the musculocutaneous nerve innervate

Answer 14

Muslces of the anterior compartment of the arm

Question 15

Spinal levels of musculocutaneous nerve

Answer 15

C5, 6

Question 16

What does the radial nerve innervate

Answer 16

Muscle of the posterior compartment of arm (triceps)

Question 17

Spinal level of radial nerve

Answer 17

C5 - T1

Question 18

Describe the cutaneous innervation of arm by musculocutaneous, axillary and radial nerves

Answer 18

• Axillary = upper arm towards shoulder
• Radial nerve = lateral upper arm and posterior arm
• Musculocutaneous nerve = Elbow
• Rest of arm = cutaneous branches of brachial plexus or intercostal nerves

Question 19

Bices brachii origin and insertion

Answer 19

Origin = scapula

Insertion = radius

Question 20

Main action(s) of biceps brachii

Answer 20

Flexion of arm/forearm

Supination of forearm

Question 21

Innervation of biceps brachii

Answer 21

Musculocutaneous nerve

Question 22

Origin and insertion of coracobrachialis muscle

Answer 22

Origin = scapula

Insertion = humerus

Question 23

Main action of coracobrachialis muscle

Answer 23

Adduction/flexion of arm

Question 24

Innervation of coracobrachialis muscle

Answer 24

Musculocutaneous nerve

Question 25

Origin and insertion of brachialis muscle

Answer 25

Origin = humerus

Insertion = ulna

Question 26

Main action of brachialis muscle

Answer 26

Flexion of forearm

Question 27

Innervation of brachialis muscle

Answer 27

Musculocutaneous nerve

Question 28

Origin and insertion of triceps brachii muscle

Answer 28

Origin = scapula/humerus

Insertion = ulna

Question 29

Main actions of triceps brachii muscle

Answer 29

Extension of arm/forearm

Adduction of arm

Question 30

Innervation of triceps brachii muscle

Answer 30

Radial nerve

Question 31

Origin and insertion of the brachio-radialis muscle

Answer 31

Origin = humerus

Insertion = radius

Question 32

Main action of brachio-radialis muscle

Answer 32

Flexion of forearm

Question 33

Innervation of brachio-radlias muscle

Answer 33

Radial nerve

Question 34

Define the cubital fossa

Answer 34

Pathway for neurovascular bundles to run from arm to forearm

Question 35

Define the boundaries of the cubital fossa

Answer 35

Pronator teres muscle = medial

Brachioradialis muscle = lateral

Superior = imaginary line between medial and lateral epicondyles of humerus

Question 36

Describe the spatial relationships of the vessles in the cubital fossa

Answer 36

• Brachial artery lateral to median nerve
• Median cubital vein most superficial

Question 37

Describe the transfer of force through the forearm from the hand

Answer 37

1. Hand to radius
2. Radius to ulna via interosseus membrane
3. Ulna to humerus

Question 38

Functions of the interosseus membrane

Answer 38

• Transmit force from the radius to the ulna
• Prevent dislocation during pronation/supination movement

Question 39

Describe the strengthening of the elbow joint

Answer 39

• Enclosed in a capsule
• Reinforced by:
  
  • Radial collateral ligament
  • Annular ligament
  • Ulnar collateral ligament

Question 40

What allows the radius to rotate on the surface of the humerus

Answer 40

Annular ligament