Neurology of upper limb

Question 1

memorise this diagram

Answer 1

Question 2

What is the brachial plexus?

Answer 2

One of the somatic plexuses that supplies the upper limb.

Question 3

Which spinal nerve roots form the brachial plexus?

Answer 3

The anterior rami of C5-T1.

Question 4

Which spinal nerve root is associated with shoulder abduction?

Answer 4

C5

Question 5

Which spinal nerve roots are associated with elbow extension?

Answer 5

C7/8

Question 6

Which spinal nerve root is associated with finger abduction?

Answer 6

T1

Question 7

Which spinal nerve roots are associated with wrist extension?

Answer 7

C5/6

Question 8

Which spinal nerve roots are associated with wrist flexion?

Answer 8

C6-8

Question 9

What forms the apex of the axilla?

Answer 9

The cervico-axillary inlet.

Question 10

what forms the base of the axilla?

Answer 10

The axillary fossa.

Question 11

Which muscles form the anterior wall of the axilla?

Answer 11

Pectoralis major and pectoralis minor.

Question 12

What structures form the medial wall of the axilla?

Answer 12

Serratus anterior and ribcage.

Question 13

Which muscles form the posterior wall of the axilla?

Answer 13

Subscapularis, teres major, latissimus dorsi, and the long head of triceps brachii.

Question 14

what structure forms the lateral wall of the axilla?

Answer 14

The humerus.

Question 15

What is the origin of the axillary nerve?

Answer 15

It is a branch of the posterior cord of the brachial plexus (root values C5, C6).

Question 16

Through which space does the axillary nerve exit the axilla?

Answer 16

The quadrangular space.

Question 17

Which muscles does the axillary nerve innervate?

Answer 17

Deltoid
Teres minor
Long head of triceps brachii

It also innervates the glenohumeral joint.

Question 18

How can the axillary nerve be injured?

Answer 18

It can be injured in shoulder dislocations.

Question 19

What are the effects of an axillary nerve injury?

Answer 19

Loss of abduction
Weakened flexion, extension, and rotation
‘Flat shoulder deformity’
Sensory loss over the lateral upper arm

Question 20

What is the origin of the musculocutaneous nerve?

Answer 20

It is a branch of the lateral cord of the brachial plexus (root values C5-C7).

Question 21

Which muscle does the musculocutaneous nerve pierce?

Answer 21

It pierces the coracobrachialis.

Question 22

What is the function of the musculocutaneous nerve in the anterior compartment of the arm?

Answer 22

It provides motor innervation to the flexors of the arm.

Question 23

Which bone does the musculocutaneous nerve give a branch to?

Answer 23

It gives a branch to the humerus at the nutrient foramen.

Question 24

What does the musculocutaneous nerve continue as in the forearm?

Answer 24

It continues as the lateral cutaneous nerve of the forearm (sensory only).

Question 25

What can cause musculocutaneous nerve injury?

Answer 25

Muscular compression or stretch Shoulder injury Direct trauma

Question 26

What are the effects of musculocutaneous nerve injury?

Answer 26

Reduced and tingling sensation in the lateral skin of the forearm Reduced strength of elbow flexion

Question 27

What is the origin of the median nerve?

Answer 27

The lateral and medial cords of the brachial plexus (root values C6-T1).

Question 28

What does the median nerve innervate? (motor and sensory)

Answer 28

Motor innervation: Muscles of the anterior forearm (except flexor carpi ulnaris and medial ½ of flexor digitorum profundus) and hand Sensory innervation: Lateral palm of the hand and three digits

Question 29

What is the origin of the ulnar nerve?

Answer 29

The medial cord of the brachial plexus (root values C8, T1).

Question 30

What does the ulnar nerve innervate? (motor and sensory)

Answer 30

Motor innervation: Flexor carpi ulnaris, medial ½ of flexor digitorum profundus, and hand Sensory innervation: Medial palm of the hand and 1½ digits

Question 31

What is the origin of the radial nerve?

Answer 31

The posterior cord of the brachial plexus (root values C5-T1).

Question 32

What does the radial nerve innervate? (motor and sensory)

Answer 32

Motor innervation: Posterior compartment of arm and forearm (extensors) Sensory innervation: Skin on the posterior arm, forearm, and dorsolateral hand

Question 33

What are the 4 effects of median nerve damage above the elbow?

Answer 33

Weak wrist flexion Loss of forearm pronation Ape hand deformity Benediction sign

Question 34

What 2 conditions can cause median nerve damage at the wrist?

Answer 34

Wrist laceration Carpal tunnel syndrome

Question 35

What are the 2 effects of ulnar nerve damage at the elbow?

Answer 35

Cubital tunnel syndrome → Claw hand Benediction sign

Question 36

What are the 2 effects of ulnar nerve damage at the wrist?

Answer 36

Guyon’s canal cyst → Claw hand Benediction sign

Question 37

What are the effects of radial nerve damage in the axilla?

Answer 37

Saturday night/honeymoon palsy Wrist drop Weak forearm extension and supination

Question 38

What is Wartenberg syndrome?

Answer 38

Nerve entrapment beneath brachioradialis tendon.

Question 39

What causes Erb-Duchenne’s palsy?

Answer 39

damage to C5/C6 roots, often caused by: - Shoulder dystocia during a difficult birth - Head/shoulder stretch injuries

Question 40

Which 3 nerves are most affected in Erb-Duchenne’s palsy?

Answer 40

Suprascapular nerve Axillary nerve Musculocutaneous nerve

Question 41

What 3 muscles are paralyzed in Erb-Duchenne’s palsy?

Answer 41

Deltoid Biceps brachii Brachialis

Question 42

What is the characteristic arm position in Erb-Duchenne’s palsy?

Answer 42

‘Waiter’s tip’ position → The arm hangs medially rotated and cannot be abducted.

Question 43

What sensory loss occurs in Erb-Duchenne’s palsy?

Answer 43

There is a loss of sensation in areas supplied by the affected nerves.

Question 44

What causes Klumpke’s paralysis?

Answer 44

Damage to the lower roots (C8/T1).

Question 45

What sensory symptoms are present in Klumpke’s paralysis?

Answer 45

C8/T1 dermatome numbness.

Question 46

What motor deficits occur in Klumpke’s paralysis?

Answer 46

Atrophy of the arm and/or hand Paralysis of intrinsic hand muscles

Question 47

what additional symptom can occur in Klumpke’s paralysis?

Answer 47

Persistent pain.

Question 48

What happens if T1 is affected in Klumpke’s paralysis?

Answer 48

It can lead to Horner’s syndrome (ptosis/miosis).

Question 49

What are the 3 branches of the thoracoacromial artery?

Answer 49

Acromial branch Deltoid branch Pectoral branch