Ulnar Nerve Palsy (OSCE Guide)

ulnar_nerve_palsy
1/03/2020

Ulnar Nerve Palsy (OSCE Guide)

The examination of hand for neuropathies is commonly encountered at OSCE stations. Ulnar Claw-hand is a very characteristic finding in Ulnar nerve palsy.

Firstly, introduce yourself and get consent before you proceed to examine the patient.


ULNAR NERVE PALSY – EXAMINATION

Given below is a targeted examination for Ulnar nerve palsy. But remember to examine other nerves (Median & Radial) to exclude multiple nerve involvement.

  1. Ask the patient to spread out the hands for you and try to spot diagnose the “Ulnar claw hand” (Clawing of the medial two fingers of the hand).
  2. Inspect carefully both the palmar and dorsal aspect of the hands and look for,
    • Wasting of hypothenar eminence (compare with the other side).
    • Dorsal guttering (due to wasted Interossei muscles) – Palpate the 1st finger web where the wasting is often obvious.
  3. Examine the functions of the muscles supplied by the Ulnar nerve.
    • Palmar Interossei – Ask the patient hold a card between two fingers while you attempt to pull it away using the same two fingers.
    • Dorsal Interossei – Ask the patient to keep the hand on a flat surface and spread out the fingers against resistance.
    • Adductor Pollicis – Ask the patient hold a paper between the thumb and the radial aspect of the index fingers while you attempting to pull it away. Flexion of the terminal phalanx of the thumb to hold the paper indicates a positive Froment’s sign.
  4. Examine the sensory distribution.
    • High lesions – There is an area of sensory loss over both palmar & dorsal aspects of the medial side of the hand and medial one and half fingers.
    • Low lesions – There is an area of sensory loss only over the palmar aspect of the medial side of the hand and medial one and half fingers.
  5. Try to identify a probable aetiology.
    • Look for depigmented anaesthetic patches and Ulnar nerve thickening at the elbow (Leprosy).
    • Look for scars on the forearm (trauma).
  6. Offer to assess the patient’s quality of life.

PRESENTATION

There is marked clawing of the ring and little fingers of the right hand and there is wasting of hypothenar eminence with dorsal guttering, but the thenar eminence is not affected. The actions of palmar and dorsal interossei are impaired and Froment’s sign is positive.

The opposition of the thumb and finger extension is intact. There is an area of sensory loss over the palmar aspect of the medial side of the hand and medial one and half fingers. There is no hypopigmented patches or ulnar nerve thickening and there are no visible scars on the forearm.

So my tentative diagnosis is right-sided Ulnar nerve palsy, probably a lower lesion.



FREQUENTLY ASKED QUESTIONS

1. What is “Clawing”?

It is the hyperextension of the metacarpophalangeal joints and flexion of proximal and distal interphalangeal joints.

2. Why does it occur?

It is due to paralyzed Interossei and Lumbricals with unopposed action of long flexors and extensors.

3. What is “Ulnar claw hand”?

The clawing is only obvious in medial two fingers (Because lateral two Lumbricals which are supplied by the median nerve are spared).

4. What is the “Ulnar paradox”?

Surprisingly, high division of the ulnar nerve (anywhere hand’s breadth above the wrist) causes less clawing than the lower lesions.

5. What is the anatomical basis of the Ulnar paradox?

In higher lesions the innervation to the medial half of Flexor Digitorum Profundus is also lost, causing less intense flexion of the fingers.

6. How do you differentiate?

From the degree of clawing and the area of sensory involvement (see examination).

7. What are the muscles that are innervated by the Ulnar nerve?

1. Flexor Carpi Ulnaris.
2. Medial half of Flexor Digitorum Profundus.
3. All Palmar Interossei.
4. All dorsal Interossei.
5. 3rd & 4th Lumbricals.
6. Adductor Pollicis

8. What is the basis of Forment’s sign?

The patient tries to compensate for the ‘lost’ adduction of the thumb by flexion of it (with Flexor Pollicis Longus which is supplied by the Median nerve).

9. What are the causes of Ulnar nerve palsy?

1. Leprosy (often bilateral).
2. Laceration over the wrist or anywhere along its course.
3. Fracture medial epicondyle.
4. Dislocation of elbow.
5. Cubital tunnel syndrome.
6. Degenerative arthritis.
7. Malunion of fractures of the lower end of the humerus (Tardae Ulna nerve palsy).

10. What are the surgical options for Ulnar nerve palsy you know of?

1. Ulnar nerve decompression.
2. Ulnar nerve anterior transposition.
3. Medial epicondylectomy.

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Carpal Tunnel Syndrome (OSCE Guide)

1/03/2020

Carpal Tunnel Syndrome (OSCE Guide)

The examination of hand for neuropathies is commonly encountered at OSCE stations. One of the most common scenarios would be carpal tunnel syndrome.

Firstly, introduce yourself and get consent before you proceed to examine the patient.


CARPAL TUNNEL SYNDROME – EXAMINATION

Usually, the command is to examine the hands of the patient, but sometimes you might be given a clue like “This lady presented with tingling sensation in her hands”. The disease is often bilateral.

  1. Ask the patient to spread out the hands for you.
  2. Look for,
    • Wasting of thenar muscles.
    • Scar of a previous carpal tunnel decompression surgery.
  3. Examine the functions of the muscles supplied by the Median nerve.
    • Abductor Pollicis Brevis – Ask the patient to place the dorsum of the hand on a flat surface and lift the thumb towards the ceiling against resistance (Pen touch test).
    • b. Opponens Pollicis – This muscle is usually not tested as it may also be supplied by the ulnar nerve ( an anatomical variation).
  4. Examine the sensory distribution.
    • There is an area of sensory loss over the palmar aspect of the lateral three and a half fingers.
    • However, the sensation over the thenar eminence is preserved.
  5. Special Signs to elicit,
    • Tinel’s Test – Tap over the flexor aspect of the wrist over the midline. If the patient feels a tingling sensation over the distribution of the median nerve, the test is positive.
    • Phalen’s Test – Ask the patient to flex the wrists maximally and keep for one minute. If the patient feels pain in the hands, the test is considered positive.
  6. Try to identify a probable aetiology.
    • Obesity.
    • Hypothyroidism – Goiter? Facial puffiness? Loss of lateral third of eyebrows?
    • Rheumatoid arthritis – Shawn neck deformity? Boutnier’s deformity? Z thumb?
  7. Offer assessment of the patient’s quality of life (QOL).
    • Nocturnal and early morning worsening of symptoms.
    • Effects on occupation or activities of daily living (eg: Washing clothes).

PRESENTATION

This patient who presented with tingling sensation of hands has bilateral thenar muscle wasting but there is no wasting of hypothenar eminence or dorsal guttering. There are no visible surgical scars, suggestive of previous carpal tunnel decompression surgery. Her opposition of the thumbs is weak and the pen touch test is positive, but there is no weakness in finger adduction or extension. There is an area of sensory loss over the palmar aspect of the lateral three and a half fingers and no other areas of sensory loss. Tinel’s test and Phalen’s test are positive. So my tentative diagnosis is bilateral Carpal Tunnel Syndrome (CTS) and I would like to assess her functional disability and probable aetiology.



FREQUENTLY ASKED QUESTIONS

1. What is Carpal Tunnel Syndrome?

It is the symptomatic compression of the median nerve at the carpal tunnel where it runs deep to the flexor retinaculum (Commonest entrapment neuropathy).

2. What are the boundaries of the carpal tunnel?

Roof – Flexor retinaculum. Medial (Ulnar) – Pisiform & Hook of Hamate. Lateral (Radial) – Scaphoid and Trapezius. Palmar aspect – Transverse carpal ligament.

3. What are the structures that pass through the carpal tunnel?

1. Median nerve.
2. Four tendons of Flexor Digitorum Superficialis.
3. Four tendons of Flexor Digitorum Profundus.
4. Tendon of Flexor Pollicis Longus.
5. Tendon of Flexor Carpi Ulnaris (in a separate compartment).

4. What are the structures that pass over the carpal tunnel?

1. Palmar cutaneous branch of the Median nerve.
2. Ulnar nerve.
3. Ulnar artery.
4. Tendon of Palmaris Longus.

5. Why not the sensation over the radial aspect of the palm is affected?

Because the palmar cutaneous branch of the Median nerve is given away proximal to the flexor retinaculum and which passes over it.

6. What are the muscles in hand which are innervated by the Median nerve?

1. All thenar muscles except Adductor Pollicis.
2. Radial two Lumbricals.

7. Name one investigation to confirm your clinical diagnosis?

Nerve conduction studies (NCS).

8. What are the known causes of carpal tunnel syndrome?

1. Obesity.
2. Pregnancy.
3. Hypothyroidism.
4. Diabetes Mellitus.
5. Rheumatoid Arthritis.

9. What are the differential diagnosis?

1. Cervical rib.
2. Cervical spondylosis.
3. Pancoast’s syndrome.

10. What is the surgery?

Carpal tunnel decompression by longitudinally dividing the flexor retinaculum in full length in a bloodless field under local anesthesia.

11. What are other non-surgical treatment options?

1. Local steroid injection.
2. Splinting of the wrist at night.
3. Treating the underlying cause.
Fig

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