Anatomy

Question 1

Subclavian line insertion

a) Thin patients
b) Fat patients

Answer 1

a) 0.5cm below and 1cm lateral to midpoint of clavicle

b) 2cm below and 1cm lateral to midpoint of clavicle

Question 2

Azygos lobe

a) Frequency
b) Position on CXR
c) Name of sign

Answer 2

a) 0.5%
b) Right upper zone, behind right medial clavicle
c) Reverse comma sign

Question 3

Laryngeal innervation

a) Recurrent laryngeal nerve* - supplies all but which muscle of the larynx?
b) Sensory innervation
c) Importance of posterior cricoarytenoid

*also known as inferior laryngeal nerve

Answer 3

a) Cricothyroid - this is supplied by superior laryngeal nerve

b) Supraglottic - superior laryngeal nerve
Infraglottic - inferior laryngeal nerve

c) Only muscle that can open the true vocal cords
Paralysis may lead to asphyxiation

Question 4

Brachial plexus injury

a) Erb’s
b) Intermediate
c) Klumpke’s
d) Flail limb

Answer 4

a) Upper brachial plexus (C5-6 roots):
• Paralysis of deltoid and biceps.
• Intact wrist and digital flexion/extension
- Waiter’s tip sign - failure of shoulder abduction, elbow flexion, forearm supination and wrist extension
(common obstetric birth injury)

b) C5-7 roots:
• Paralysis of deltoid, biceps, AND wrist and digital extension.
• Intact wrist and digital flexion.

c) Lower brachial plexus (C8-T1)
- deficit of all of the small muscles of the hand (ulnar and median nerves)
- “claw hand (fingers in flexion)
(more common in traumatic accidents e.g. climbing)

d) • Weakness of all arm/hand movements
With or without Horner’s

Question 5

Ulnar nerve

a) Passes through which canal
b) Which intrinsic muscles does it not innervate

Answer 5

a) Guyon’s

b) LOAF: lateral lumbricals, opponens/abductor/flexor pollicis brevis
(but it does innervate ADductor pollicis brevis, hence pinch grip weakens - paper test)

Question 6

Oblique fissure - anatomical landmark

Answer 6

Medial border of scapula when arm abducted