Upper Limb Neurology

Question 1

Inspection of the wasted hand(s)

Answer 1

Age

• loss of muscle bulk normal in elderly
• symmetrical - wasted muscles NOT weak

Arthritis

• wasting with minimal weakness

Pupils

• Horner’s syndrome: ptosis, miosis, anhydrosis
• = C8/T1 root or cord lesion (generally unilateral)

Question 2

What are the typical striatal hand deformities?

Answer 2

“Striatal hand” - associated with parkinsonism

• Flexion of MCP
• Extension of PIP
• Flexion of DIP
• No evidence of joint swelling or tenderness

Question 3

What does wasting of abductor pollicis brevis signify?

Answer 3

Median nerve lesion

Weakness in abduction of the thumb

Question 4

How do you differentiate between a distal and proximal median nerve lesion?

Answer 4

Distal median nerve lesion ( entrapment of median nerve in carpal tunnel)

Weakness confined to Abductor pollicis longus

Proximal median nerve lesion (at the elbow)

Deep flexors of index finger (Benediction sign)

Weakness in flexor pollicis longus

Question 5

What does wasting of abductor digiti minimi

and the first dorsal interossei signify?

Answer 5

Ulnar nerve lesion

Weakness in abduction of the fingers

Question 6

How do you differentiate between a proximal and distal ulnar nerve lesion?

Answer 6

Proximal (at the elbow)

Weakness in ADM and 1st DI

Severe cases - also weakness of deep flexor of little finger

Distal (deep palmar branch of ulnar)

Weakness isolated to abduction of finger

No sensory loss

Question 7

What are the roots that make up the brachial plexus?

Answer 7

C5 C6 C7 C8 T1

Question 8

What are 4 differential diagnosis for wrist drop?

Answer 8

Compression of radial nerve in spiral groove of humerus

Vascular (infarction of vaso nervorum) - especially in diabetes

C7/8 root or plexus lesion

Corticospinal lesions

Question 9

What is the clinical presentation of a posterior interosseus nerve lesion?

What are the potential causes of a posterior interossesus nerve lesion?

Answer 9

Radial deviation of wrist

Due to weakness of extensor carpi ulnaris

No sensory loss and reflexes normal

Causes:

Entrapment

Mononeuritis multiplex / simplex from diabetes or collagen disease

Question 10

What is the most common radial nerve lesion and how does it present?

Answer 10

Compression of radial nerve in the spiral groove

Weakness of brachio-radialis, wrist extension and finger extension

Brachioradialis reflex is reduced or absent

Question 11

What are the features of a C7/8 root lesion or plexus lesion?

Answer 11

Wrist drop (weakness of wrist and finger extensor)

Weakness in triceps extension

Decreased or absent triceps reflex

Question 12

What are the features of a corticospinal wrist drop?

Answer 12

Increased tone in upper limb

Generalised weakness of muscles in upper limb

Pyridamal pattern of weakness

Affecting deltoid, triceps and finger extension

Question 13

Deltoid

Myotome

Nerve supply

Nerve roots

Answer 13

Shoulder ABduction

Axillary nerve

C5 / 6 roots

Question 14

Biceps

Myotome

Nerve Supply

Roots

Answer 14

Elbow flexion

Musculocutaneous nerve

C5 / 6 roots

Question 15

Triceps

Myotome

Nerve supply

Roots

Answer 15

Elbow extension

Radial nerve

C7 / 8 roots

Question 16

Brachioradialis

Myotome

Nerve Supply

Roots

Answer 16

Elbow flexion (thumb up to nose)

Radial nerve

C5 / 6 roots

Question 17

What does isolated deltoid weakness signify?

What are the associated clinical findings?

Answer 17

Axillary nerve lesion

Fixate the scapula to ensure it doesn’t move during testing

Associated with sensory loss over the deltoid

Question 18

What are the characteristics of a C5 / 6 cord, root or plexus lesion?

Answer 18

Weakness of deltoid, brachioradialis, biceps

Distal plexus lesions may spare

Supraspinatus, infraspinatus

Serratus anterior

Question 19

Weakness of all muscles in one arm

What conditions are associated with:

1. Areflexia?
2. Hyperreflexia?

Answer 19

Areflexia - usually signifies brachial plexus lesion LMN

Check for Horner’s and C5-T1 sensory loss

Dissociated senosry loss - intrinsic cord lesions (syringomyelia)

Hyperreflexia

Consider cortical signs UMN

Right hemiparesis - dysphasia / aphasia

Left hemiparesis - neglect (sensory and visual), apraxia