Answers for Medical Finals Quiz April 2006

Below are the author's answers and teaching points for this Quiz.

Question 1

April Quiz Question 1
(Click on image for enlarged view. The click your brower's BACK button to return to this page)

Which one of the following conditions could not cause this appearance?

(a) Pancoast's tumour
(b) Carpal tunnel syndrome
(c) Motor neurone disease
(d) Monomelic amyotrophy
(e) Syringomyelia
Answer: (b) Carpal tunnel syndrome

Carpal tunnel syndrome comprises of entrapment of the median nerve, in a narrow tunnel as it enters the hand under the flexor retinaculum on the flexor aspect at the wrist. There are nine tendons that travel through this narrow canal, so it is susceptible to compression. The median nerve supplies: Lateral two lumbricals, Oponens pollicis, Abductor pollicis brevis and Flexor pollicus brevis. (LOAF).

This picture demonstrates muscle wasting of the small muscles of the hand. These muscles are not supplied by the median nerve. They are supplied primarily by the ulnar nerve. Therefore any lesion that can interrupt any of the cords or the cervical roots that ultimately form the ulnar nerve will cause such wasting.

Question 2

A 42 year-old teacher attends her dentist for a check-up. She notices on her buccal mucosa a white patch with a lace-like appearance. It is painless.

What is the most likely diagnosis?

(a) Systemic Lupus Erythromytosis
(b) Squamous cell carcinoma
(c) Candidiasis
(d) Lichen planus
(e) Leukoplakia
Answer: (d) Lichen planus

Lichen planus classically gives a lace-like reticular appearance on the buccal mucosa. It is painless and may only be identified incidentally. This distribution is known as Wickham's straie.

Lichen planus is also observed at the wrists where papular (raised) lesions are found which are intensely itchy. Lichen planus exhibits the Koebner's phenomenon whereby it is adopted within an area of excoriation.

Question 3

Look at this photograph and answer the following questions..

April Quiz Question 3
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Which of the following muscle weakness causes this appearance?

(a) Trapezius
(b) Serratus anterior
(c) Deltoid
(d) Levator scapula
(e) Pectoralis major
Answer: (b) Serratus anterior

This picture demonstrates a winged scapula.

Question 4

Damage to which of the following nerves could cause this appearance (as shown in the picture in question 3 above)?
(a) Spinal accessory nerve
(b) Musculocutaneous nerve
(c) Axillary nerve
(d) Long thoracic nerve
(e) Lower subscaular nerve
Answer: (d) Long thoracic nerve

Serratus anterior holds the scapula against the thoracic wall and is supplied by the long thoracic nerve.

Question 5

A 64 year-old gentleman attends for ultrasound of the abdomen. An incidental finding of a 4.0cm infra-renal abdominal aortic aneurysm is observed at ultrasound.

April Quiz Question 5
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Which of the following is the most appropriate management?

(a) Refer to vascular surgeon for urgent repair
(b) Refer to vascular surgeon for elective repair
(c) Nothing
(d) Arrange follow-up ultrasound in 6-12 months
(e) Refer for angiography
Answer: (d) Arrange follow-up ultrasound in 6-12 months

The elective management of abdominal aortic aneurysms may differ slightly between centres. The general consensus is as follows:

  • Greater than 5.5cm => elective repair. This may be either open surgical repair or by endovascular stent placement. (This may be 5cm for women.)
  • 4.5 - 5.5cm => Six monthly ultrasound assessment
  • 3.0 - 4.5cm => Annual ultrasound assessment

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