Peripheral nerve injuries/palsies

Question 1

What is Erb-Duchenne paralysis?

Answer 1

Damage to C5,6 roots, characterized by winged scapula.

May be caused by a breech presentation.

Question 2

What is Klumpke’s paralysis?

Answer 2

Damage to T1, resulting in loss of intrinsic hand muscles due to traction.

Question 3

What is carpal tunnel syndrome?

Answer 3

Carpal tunnel syndrome is caused by compression of the median nerve in the carpal tunnel.

Question 4

What are the common symptoms of carpal tunnel syndrome?

Answer 4

Pain and pins and needles in the thumb, index, and middle finger. Unusually, the symptoms may ‘ascend’ proximally. Patients often shake their hand to obtain relief, classically at night.

Question 5

What are the examination findings in carpal tunnel syndrome?

Answer 5

Weakness of thumb abduction (abductor pollicis brevis), wasting of the thenar eminence (NOT hypothenar), Tinel’s sign (tapping causes paraesthesia), and Phalen’s sign (flexion of wrist causes symptoms).

Question 6

What are the causes of carpal tunnel syndrome?

Answer 6

Causes include idiopathic reasons, pregnancy, oedema (e.g., heart failure), lunate fracture, and rheumatoid arthritis.

Question 7

What are the electrophysiological findings in carpal tunnel syndrome?

Answer 7

Motor and sensory prolongation of the action potential.

Question 8

What is the recommended treatment for mild-moderate carpal tunnel syndrome?

Answer 8

NICE recommends a 6-week trial of conservative treatments.

Question 9

What conservative treatments are suggested for carpal tunnel syndrome?

Answer 9

Corticosteroid injection and wrist splints at night, particularly useful if transient factors are present (e.g., pregnancy).

Question 10

What is the surgical treatment for severe carpal tunnel syndrome?

Answer 10

Surgical decompression (flexor retinaculum division) if there are severe symptoms or if symptoms persist with conservative management.

Question 11

What are the two nerves that the sciatic nerve divides into?

Answer 11

The sciatic nerve divides into the tibial and common peroneal nerves.

Question 12

Where does injury to the common peroneal nerve often occur?

Answer 12

Injury often occurs at the neck of the fibula.

Question 13

What is the most characteristic feature of a common peroneal nerve lesion?

Answer 13

The most characteristic feature is foot drop.

Question 14

What are the other features of a common peroneal nerve lesion?

Answer 14

Other features include:
- weakness of foot dorsiflexion
- weakness of foot eversion
- weakness of extensor hallucis longus
- sensory loss over the dorsum of the foot and the lower lateral part of the leg
- wasting of the anterior tibial and peroneal muscles.

Question 15

What is the radial nerve a continuation of?

Answer 15

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

Question 16

Where does the radial nerve lie in the axilla?

Answer 16

It lies posterior to the axillary artery on subscapularis, latissimus dorsi, and teres major.

Question 17

How does the radial nerve enter the arm?

Answer 17

It enters between the brachial artery and the long head of triceps (medial to humerus).

Question 18

What path does the radial nerve take around the humerus?

Answer 18

It spirals around the posterior surface of the humerus in the groove for the radial nerve.

Question 19

What happens at the distal third of the lateral border of the humerus?

Answer 19

The radial nerve pierces the intermuscular septum and descends in front of the lateral epicondyle.

Question 20

Where does the radial nerve divide into branches?

Answer 20

At the lateral epicondyle, it lies deeply between brachialis and brachioradialis where it divides into a superficial and deep terminal branch.

Question 21

What does the deep branch of the radial nerve become?

Answer 21

It crosses the supinator to become the posterior interosseous nerve.

Question 22

What muscles are innervated by the radial nerve (motor)?

Answer 22

Triceps, Anconeus, Brachioradialis, Extensor carpi radialis.

Question 23

What muscles are innervated by the posterior interosseous branch?

Answer 23

Supinator, Extensor carpi ulnaris, Extensor digitorum, Extensor indicis, Extensor digiti minimi, Extensor pollicis longus and brevis, Abductor pollicis longus.

Question 24

What sensory area does the radial nerve supply?

Answer 24

The area of skin supplying the proximal phalanges on the dorsal aspect of the hand (excluding the little finger and part of the ring finger).

Question 25

What is the effect of paralysis of the long head of triceps?

Answer 25

Minor effects on shoulder stability in abduction.

Question 26

What is the effect of paralysis of the triceps?

Answer 26

Loss of elbow extension.

Question 27

What muscles are affected by radial nerve paralysis in the forearm?

Answer 27

Supinator, Brachioradialis, Extensor carpi radialis longus and brevis.

Question 28

What is the effect of paralysis on forearm muscles?

Answer 28

Weakening of supination of prone hand and elbow flexion in mid prone position.

Question 29

What are the patterns of damage associated with radial nerve injury?

Answer 29

Wrist drop and sensory loss to a small area between the dorsal aspect of the 1st and 2nd metacarpals.

Question 30

What happens with axillary damage to the radial nerve?

Answer 30

Paralysis of triceps and the same effects as above.

Question 31

What is thoracic outlet syndrome (TOS)?

Answer 31

TOS is a disorder involving compression of the brachial plexus, subclavian artery, or vein at the thoracic outlet. It can be neurogenic or vascular; neurogenic cases account for 90%.

Question 32

What is the epidemiology of thoracic outlet syndrome?

Answer 32

The epidemiology of TOS is not well documented due to a lack of widely agreed diagnostic criteria. Patients are typically young, thin women with long necks and drooping shoulders, with peak onset in the 4th decade.

Question 33

What are the aetiological factors for thoracic outlet syndrome?

Answer 33

TOS develops from neck trauma in individuals with anatomical predispositions. This trauma can be a single acute incident or repeated stresses, with anatomical anomalies in soft tissue (70%) or osseous structures (30%).

Question 34

What is a well-known osseous anomaly associated with TOS?

Answer 34

The presence of a cervical rib is a well-known osseous anomaly associated with TOS.

Question 35

What are examples of soft tissue causes of TOS?

Answer 35

Examples include scalene muscle hypertrophy and anomalous bands.

Question 36

What are the clinical presentations of neurogenic TOS?

Answer 36

Clinical presentations include painless muscle wasting of hand muscles, hand weakness, and sensory symptoms like numbness and tingling. If autonomic nerves are involved, symptoms may include cold hands, blanching, or swelling.

Question 37

What are the clinical presentations of vascular TOS?

Answer 37

Subclavian vein compression leads to painful diffuse arm swelling with distended veins, while subclavian artery compression causes painful arm claudication and, in severe cases, ulceration and gangrene.

Question 38

What examinations are necessary for TOS?

Answer 38

Neurological and musculoskeletal examinations are necessary. Stress manoeuvres like Adson's manoeuvre may be attempted, though they have limited utility.

Question 39

What investigations are used for TOS?

Answer 39

Investigations include chest and cervical spine plain radiographs to check for osseous abnormalities, CT or MRI to rule out cervical root lesions, and venography or angiography for vascular TOS.

Question 40

What is the first-line management for neurogenic TOS?

Answer 40

Conservative management with education, rehabilitation, physiotherapy, or taping is typically the first-line management.

Question 41

When is surgical decompression warranted in TOS?

Answer 41

Surgical decompression is warranted when conservative management has failed, especially if there is a physical anomaly. Early intervention may prevent brachial plexus degeneration.

Question 42

What treatment may be preferred for vascular TOS?

Answer 42

Surgical treatment may be preferred for vascular TOS.

Question 43

What other therapies are being investigated for TOS?

Answer 43

Other therapies being investigated include botox injection.

Question 44

What is the origin of the ulnar nerve?

Answer 44

The ulnar nerve arises from the medial cord of the brachial plexus (C8, T1).

Question 45

What muscles does the ulnar nerve provide motor innervation to?

Answer 45

The ulnar nerve provides motor innervation to the medial two lumbricals, adductor pollicis, interossei, and the hypothenar muscles: abductor digiti minimi, flexor digiti minimi, and flexor carpi ulnaris.

Question 46

What is the sensory distribution of the ulnar nerve?

Answer 46

The ulnar nerve is sensory to the medial 1 1/2 fingers (palmar and dorsal aspects).

Question 47

Describe the path of the ulnar nerve.

Answer 47

The ulnar nerve travels through the posteromedial aspect of the upper arm to the flexor compartment of the forearm, then enters the palm of the hand via Guyon's canal, superficial to the flexor retinaculum and lateral to the pisiform bone.

Question 48

What does the muscular branch of the ulnar nerve supply?

Answer 48

The muscular branch supplies the flexor carpi ulnaris and the medial half of the flexor digitorum profundus.

Question 49

What does the palmar cutaneous branch of the ulnar nerve supply?

Answer 49

The palmar cutaneous branch supplies the skin on the medial part of the palm.

Question 50

What does the dorsal cutaneous branch of the ulnar nerve supply?

Answer 50

The dorsal cutaneous branch supplies the dorsal surface of the medial part of the hand.

Question 51

What does the superficial branch of the ulnar nerve supply?

Answer 51

The superficial branch provides cutaneous fibers to the anterior surfaces of the medial one and one-half digits.

Question 52

What does the deep branch of the ulnar nerve supply?

Answer 52

The deep branch supplies the hypothenar muscles, all the interosseous muscles, the third and fourth lumbricals, the adductor pollicis, and the medial head of the flexor pollicis brevis.

Question 53

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

Answer 53

'Claw hand' occurs, characterized by hyperextension of the metacarpophalangeal joints and flexion at the distal and proximal interphalangeal joints of the 4th and 5th digits, along with wasting and paralysis of intrinsic hand muscles (except lateral two lumbricals), wasting and paralysis of hypothenar muscles, and sensory loss to the medial 1 1/2 fingers (palmar and dorsal aspects).

Question 54

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

Answer 54

The effects are similar to those at the wrist; however, there is an ulnar paradox where clawing is more severe in distal lesions, along with radial deviation of the wrist.

Question 55

Radial Nerve Position

Answer 55

Question 56

Answer 56

The cutaneous sensation of the upper limb- illustrating the contribution of the radial nerve

Question 57

Radial nerve - regions innervated

Answer 57

Question 58

Muscular innervation and effect of denervation - shoulder, arm, forearm - muscle affected& effect on paralysis

Answer 58