Upper Limb Nerves

Question 1

Which cord of the brachial plexus does the musculocutaneous nerve originate from?

Answer 1

The lateral cord

Question 2

Describe the course of the musculocutaneous nerve down the arm.

Answer 2

Originates from the lateral cord of the brachial plexus
Pierces coracobrachialis and travels down the arm anterior to brachialis, but posterior to biceps brachii.
Emerges laterally to biceps tendon.

Question 3

Does the musculocutaneous nerve continue into the forearm?

Answer 3

Yes, as the lateral cutaneous nerve

Question 4

Which muscles does the musculocutaneous nerve innervate?

Answer 4

Biceps brachii
Brachialis
Coracobrachialis

Question 5

What are the motor functions of the musculocutaneous nerve?

Answer 5

Flexion at the elbow, supination of the forearm.

Question 6

What is the sensory function of the musculocutaneous nerve?

Answer 6

The lateral cutaneous nerve (which it becomes in the forearm) supplies the skin of the lateral aspect of the forearm

Question 7

Which cord of the brachial plexus is the ulnar nerve a continuation of?

Answer 7

Medial cord

Question 8

Which nerve roots does the ulnar nerve originate from?

Answer 8

C8 and T1

Question 9

Describe the anatomical course of the ulnar nerve, from the brachial plexus to the elbow

Answer 9

Originates from medial cord of brachial plexus
Descends down medial side of arm
Passes posteriorly to the medial epicondyle at elbow

Question 10

Describe the anatomical course of the ulnar nerve in the forearm and hand

Answer 10

Gives rise to the muscular branch just distally to the elbow
Descends the forearm medially, alongside the ulna
At the wrist, gives off dorsal branch and palmar branch
Travels into the hand superficially to flexor retinaculum, via the Guyon’s canal
Terminates in hand by splitting into deep and superficial branches

Question 11

Where are the muscles that the ulnar nerve innervates?

Answer 11

Anterior compartment of the forearm

Intrinsic muscles of the hand

Question 12

Which muscles in the anterior forearm does the ulnar nerve innervate?

Answer 12

Flexor carpi ulnaris

Medial half of flexor digitorum profundus

Question 13

Which intrinsic muscles of the hand are innervated by the ulnar nerve?

Answer 13

Hypothenar muscles
Medial 2 lumbricals
Adductor pollicis
Interossei

Question 14

What are the motor functions of the ulnar nerve in the anterior compartment of the forearm?

Answer 14

Flexion of the fingers

Flexion and ulnar deviation of the wrist

Question 15

What are the 3 branches of the ulnar nerve which have sensory functions?

Answer 15

Palmar cutaneous branch
Dorsal cutaneous branch
Superficial branch

Question 16

Which area of skin is supplied by the ulnar nerve?

Break this down into the 3 branches.

Answer 16

The skin of the medial 1 1/2 fingers, and the corresponding dorsal and palmar surfaces

Skin of medial half of palm = palmar cutaneous branch
Skin of medial 1 1/2 fingers and the dorsal surface = dorsal branch
Skin of medial 1/2 fingers palmar side = superficial branch

Question 17

Which nerve is a continuation of the posterior cord of the brachial plexus?

Answer 17

Radial nerve

Question 18

Give the nerve roots of the radial nerve

Answer 18

C5, C6, C7, C8 and T1

Question 19

Describe the course of the radial nerve, from its origin to its termination

Answer 19

Originates as posterior cord of brachial plexus
Exits axilla posterior to brachial artery
Travels down posterior aspect of humerus, in radial groove
Supplies triceps brachii
Wraps laterally around humerus and passes anteriorly over lateral epicondyle at elbow, passing through the cubital fossa
Terminates in forearm by splitting into deep and superficial branches

Question 20

Which of the following is the sensory branch, and which is the motor branch - deep and superficial?

Answer 20

Sensory = superficial
Motor = deep

Question 21

What muscles are innervated by the radial nerve?

Answer 21

In the arm = triceps brachii

In the forearm = posterior compartment

Question 22

What are the motor functions of the radial nerve?

Answer 22

Extension at the elbow
Extension at the wrist
Extension at the fingers

Question 23

What are the 4 sensory branches of the radial nerve?

Answer 23

Lower lateral
Posterior cutaneous branch of forearm
Posterior cutaneous branch of arm
Superficial branch

Question 24

Which areas of skin of the upper limb are supplied by the radial nerve?

Answer 24

Lateral aspect of arm, below the deltoid
Posterior surface of arm
Strip of skin down middle of posterior forearm
Dorsal surface of lateral 3 fingers (not finger tips)

Question 25

What are the nerve roots of the axillary nerve?

Answer 25

C5 and C6

Question 26

Which cord of the brachial plexus does the axillary nerve originate from?

Answer 26

Posterior cord

Question 27

Which structure does the axillary nerve exit the axilla with?

Answer 27

Posterior circumflex humeral artery

Question 28

Which muscles are innervated by the axillary nerve?

Answer 28

Teres minor

Deltoid

Question 29

What is the motor function of the axillary nerve?

Answer 29

Abduction of the arm at the shoulder

Question 30

Which area is innervated by the axillary nerve?

Which branch of the nerve is responsible for this?

Answer 30

The regimental badge area - skin over lower deltoid

Lateral cutaneous nerve of arm

Question 31

Which cords of the brachial plexus does the median nerve arise from?

Answer 31

The medial and lateral cords

Question 32

What are the nerve roots of the median nerve?

Answer 32

C5 - T1

Question 33

Describe the anatomical course of the median nerve down the arm

Answer 33

Descends the arm first of all laterally to the brachial artery, and then medially to it, but pretty much straight down the middle of the anterior side.
At the elbow, passes through the cubital fossa

Question 34

Describe the course of the median nerve through the forearm

Answer 34

Enters anterior compartment of forearm via cubital fossa
Descends forearm between flexor digitorum superficialis and flexor digitorum profundus.
Gives off anterior interosseous nerve - supplies the deep compartment of the anterior forearm

Question 35

Describe the course of the median nerve into the hand

Answer 35

Enters the hand via the carpal tunnel

Once in the hand, splits into recurrent branch and palmar digital branch

Question 36

Which forearm muscles are supplied by the median nerve?

Answer 36

Superficial compartment - all but flexor carpi ulnaris, i.e. PT, FCR, PL
Intermediate compartment - FDS
Deep compartment - lateral half of FDP, and all others

Question 37

Which branch of the median nerve supplies the deep compartment of the forearm?

Answer 37

The anterior interosseous branch

Question 38

Which branch of the median nerve supplies the thenar muscles?

Answer 38

The recurrent branch

Question 39

Which muscles are supplied by the palmar digital branch of the median nerve?

Answer 39

The lateral 2 lumbricals

Question 40

What are the names of the sensory branches of the median nerve?

Answer 40

Palmar cutaneous branch

Palmar digital branch

Question 41

Which skin is innervated by the palmar cutaneous branch of the median nerve?

Answer 41

Lateral aspect of hand

Question 42

Where does the palmar cutaneous branch of the median nerve arise?
How does it travel to its destination?

Answer 42

Arises in forearm

Travels into hand but not via carpal tunnel

Question 43

Where does the palmar digital branch of the median nerve arise?

Answer 43

In the hand

Question 44

What skin is innervated by the palmar digital branch of the median nerve?

Answer 44

Palmar surface of the lateral 3 1/2 digits, and palm below

Finger tips on the dorsal surface of 3 1/2 digits

Question 45

Which nerve roots does the musculocutaneous nerve originate from?

Answer 45

C5 - C7