Upper limb neuromuscular supply

Question 1

Which spinal roots contribute to the axillary nerve?

Answer 1

C5 + C6

Question 2

What are the sensory functions of the axillary nerve?

Answer 2

gives rise to upper lateral cutaneous nerve of the arm = innervates skin over lower deltoid (regimental badge area).

Question 3

What muscles are innervated by the axillary nerve?

Answer 3

Teres minor and deltoid

Question 4

Which mechanisms of injury can commonly affect the axillary nerve?

Answer 4

Fracture of humeral surgical neck
Shoulder dislocation

Question 5

If the axillary nerve is disrupted, which motor function if pathognomonic?

Answer 5

Unable to abduct arm to >15 degrees.

Question 6

If the axillary nerve is damaged, which sensory impairment is pathognomonic?

Answer 6

Loss of sensation over regimental badge area.

Question 7

What is era’s palsy?

Answer 7

Clinical condition resulting from damage to C5 and C6 roots of brachial plexus.

Question 8

What causes era’s palsy?

Answer 8

Excessive increase in angle between neck and shoulder = stretches nerve roots.

Question 9

In erb’s palsy, how will a patient normally hold their arm?

Answer 9

Internally rotated adduction.

**Unable to externally rotate or abduct their arm.

Question 10

Which nerve roots form the musculocutaneous nerve?

Answer 10

C5, C6, C7

Question 11

What are the motor functions of the musculocutaneous nerve?

Answer 11

Anterior compartment of arm (biceps, coarcobrachialis, brachialis)

Question 12

What are the sensory functions of the musculocutaneous nerve?

Answer 12

Innervates anterolateral aspect of forearm (lateral cutaneous nerve)

Question 13

Which movements is the musculocutaneous nerve responsible for?

Answer 13

Flexion of arm at elbow and shoulder.
Biceps also supinates forearm.

Question 14

Which mechanisms of injury can commonly damage the musculocutaneous nerve?

Answer 14

Penetrating trauma to axilla

Question 15

What clinical findings are present if there is damage to the musculocutaneous nerve?

Answer 15

Loss of sensation over anterolateral aspect of forearm
Elbow and shoulder flexion are weakened
Forearm supination is weakened

Question 16

Which nerve roots form the median nerve?

Answer 16

C6, C7, C8, T1

Question 17

What are the sensory function of the median nerve?

Answer 17

Lateral aspect of the palm (palmar cutaneous branch)
Lateral 3 and a half fingers anteriorly (digital cutaneous branch)
Lateral 3 fingertips

Question 18

What is the motor function of the median nerve?

Answer 18

Flexor (anterior) compartment of forearm (not FCU or lateral half of FDP)
Thenar muscles
Lateral 2 lumbricals

Question 19

What movements do muscles supplied by the median nerve do?

Answer 19

Forearm pronation
Wrist flexion
Digital flexion
Thumb flexion, opposition and adduction
Index and middle finger MCP flexion + IP extension

Question 20

How is the median nerve normal damaged at the elbow?

Answer 20

Supracondylar fracture of the humerus

Question 21

What characteristic sign is seen when the median nerve is damaged?

Answer 21

Hand of benediction.

Question 22

How is the median nerve often damaged at the wrist?

Answer 22

Lacerations just proximal to flexor retinaculum.

Question 23

Which nerve roots form the radial nerve?

Answer 23

C5 to T1.

Question 24

What is the motor function of the radial nerve?

Answer 24

Triceps
Extensor (posterior) muscles of forearm.

Question 25

What are the sensory innervations of the radial nerve?

Answer 25

Skin of posterior arm Lateral aspect of dorsum of hand Dorsal surface of lateral 3 and a half digits

Question 26

How can the radial nerve be damaged at the axilla?

Answer 26

Shoulder dislocation Proximal humerus fracture Excessive pressure on the nerve within the axilla

Question 27

What characteristic sign is seen with radial nerve damage?

Answer 27

Wrist drop

Question 28

How can the radial nerve be damaged at the radial groove?

Answer 28

Fracture of the humeral shaft

Question 29

How can the deep branch of the radial nerve be injured in the forearm?

Answer 29

Fracture of radial head or posterior dislocation of the radius

Question 30

How can the superficial branch of the radial nerve be injured in the forearm?

Answer 30

Stabbing or laceration of the forearm

Question 31

If the superficial branch of the radial nerve is damaged what happens to motor function?

Answer 31

No effect. **Superficial branch is purely sensory.

Question 32

If the deep branch of the radial nerve is injured, what happens to sensory function?

Answer 32

No effect.

Question 33

Which nerve roots form the ulnar nerve?

Answer 33

C8 -T1.

Question 34

What is the sensory innervation of the ulnar nerve?

Answer 34

Medial one and a half fingers and associated palm area.

Question 35

What are the motor functions of the ulnar nerve?

Answer 35

FCU Medial half FDP Intrinsic muscles of hand (except thenar muscles and lateral 2 lumbricals).

Question 36

What is a common test for ulnar nerve palsy?

Answer 36

Froment's test

Question 37

Why is the ulnar claw worse when the ulnar nerve is damaged at the wrist compared to when damaged at the elbow?

Answer 37

Because the FDP is intact.

Question 38

What are the 5 main vessels providing blood supply to the upper limb?

Answer 38

Subclavian artery Axillary artery Brachial artery Radial artery Ulnar artery

Question 39

When does the subclavian artery become the axillary artery?

Answer 39

At the lateral border of the 1st rib when it enters the axilla.

Question 40

When does the axillary artery become the brachial artery?

Answer 40

As it passes the lower border of Teres major.

Question 41

Which vessels supply the triceps?

Answer 41

The profunda brachii arteries

Question 42

When does the brachial artery become the ulnar and radial arteries?

Answer 42

It bifurcates underneath the bicipital aponeurosis after moving through the curtail fossa.

Question 43

Where do the radial and ulnar arteries terminate?

Answer 43

Anastamose in the hand by forming two arches (superficial palmar arch and deep palmar arch)

Question 44

Which palmar arch gives rise to the digital arteries?

Answer 44

Superficial palmar arch

Question 45

What are the major superficial veins of the upper limb?

Answer 45

Cephalic and basilic

Question 46

Which vein connects the cephalic and basilica veins?

Answer 46

Median cubital vein

Question 47

Which is the more medial superficial vein?

Answer 47

Basilic vein

Question 48

Which is the more lateral superficial vein?

Answer 48

Cephalic vein

Question 49

Which are the largest deep veins of the arm?

Answer 49

Brachial veins

Question 50

Where are the brachial veins situation?

Answer 50

Either side of the brachial artery