1 Peripheral nerve lesions

Question 1

What are the key dermatomes of the upper limb?

Answer 1

C5 lateral elbow surface.
C7 middle finger.
T1 medial elbow surface.

Question 2

What is Erb’s palsy caused by?

Answer 2

Excessive stretching of C5+6 nerve roots during delivery.

Violent falls forcing head and shoulder apart.

Question 3

What are the symptoms of Erb’s palsy?

Which muscles are affected in each of these?

Answer 3

Waiter's tip position.
Adducted shoulder: loss of deltoid.
Medially rotated arm: loss of infraspinatus + teres minor.
Extended elbow: loss of biceps.
Pronated forearm: loss of brachialis.

Question 4

What is Klumpke’s palsy caused by?

Answer 4

Excessive pulling of arm during delivery or grasping to prevent a fall.
Damage to C8 and T1.

Question 5

What does Kulmpke’s palsy cause?

Answer 5

Ulnar claw hand.

Paralysed lumbricals 4+5 leads to permanent MPJ extension and IPJ flexion.

Question 6

What is cubital tunnel syndrome caused by?

Answer 6

Constructing fascial bands.
Direct compression.
Repetitive elbow flexion and extension.

Question 7

What are the symptoms of cubital tunnel syndrome?

Answer 7

Ulnar claw hand plus elbow pain.

Question 8

What is Klumpke’s palsy associated with?

Answer 8

Horners syndrome.

Question 9

What is Horner’s syndrome?

Answer 9

Ptosis.
Miosis (pupillary constriction).
Anhidrosis.
Vasodilation.

Question 10

What does radial nerve palsy result in?

Answer 10

Wrist drop: inability to extend wrist.

Extensors in forearm are paralysed.

Question 11

What does medial nerve injury cause?

Answer 11

Hand of benediction.

Question 12

What is the hand of benediction?

Answer 12

Inability to flex digits 1 to 3. Weakened flexion of 4 + 5.

When trying to make a fist, form hand of benediction.