MyPasTest: MRCS A Online - Jan Exam 2015
04. Anatomy; Upper limb & Breast (120Qs)
----------------------------------------------------------------------------------------------------------------------------------
01. Theme: Radial nerve injury
A Compression at the elbow
B Fracture of the mid-humerus
C Axillary compression
D Laceration at the wrist.
For each of the scenarios below describe the level of injury. Pick the most appropriate option from the
Page
above list. Each option may be used once only, more than once or not at all. 244
Scenario 1
A 25-year-old man presenting with weakness of the wrist and hand with paralysis of the triceps muscle and an
absent triceps reflex.
A - Compression at the elbow« YOUR ANSWER
C - Axillary compression« CORRECT ANSWER
In very high lesions, the radial nerve may be compressed in the axilla, eg crutch palsy.
Scenario 2
A 25-year-old man presenting with a wrist drop with inability to extend the metacarpophalangeal joints together
with paraesthesia of the skin over the anatomical snuffbox.
B - Fracture of the mid-humerus« CORRECT ANSWER
In high lesions with fractures of the humerus or due to prolonged tourniquet pressure, there is weakness
of the radial extensors of the wrist and numbness over the anatomical snuffbox. In comparison to low
radial nerve deficits, which include loss of digital extension and thumb extension, high radial nerve
deficits also result in loss of wrist extension.
Scenario 3
A 25-year-old man presenting with failure of extension of the metacarpophalangeal joints with weakness of thumb
extension and interphalangeal extension.
C - Axillary compression« YOUR ANSWER
A - Compression at the elbow« CORRECT ANSWER
In low radial nerve lesions, ie those due to fractures or dislocations at the elbow, the posterior
interosseus nerve may be injured and the patient is unable to perform finger extension with weakness of
thumb abduction and extension. In comparison to low radial nerve deficits (i.e. posterior interosseus
nerve palsy), which include loss of digital extension and thumb extension, high radial nerve deficits also
result in loss of wrist extension.
02. Which one of the following muscles in the hand is supplied by the median nerve? Single best answer
question – choose ONE true option only.
Radial two interossei« YOUR ANSWER
Abductor pollicis brevis« CORRECT ANSWER
Ulnar two lumbricales
Adductor pollicis
-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Dr Mohammed Shamsul Islam Khan, Medical Officer, Clinical Neuro-Surgery, National Institute of Neuro-Sciences and Hospital
Sher-E-Bangla Nagar, Dhaka-1207, Bangladesh. Mobile: +880 1713 455 662, E-mail:
, MyPasTest: MRCS A Online - Jan Exam 2015
04. Anatomy; Upper limb & Breast (120Qs)
----------------------------------------------------------------------------------------------------------------------------------
Extensor pollicis.
The median nerve supplies the following structures in the hand:
The abductor pollicis brevis, flexor pollicis brevis, opponens pollicis
The radial two lumbricales
The palmar surface of the radial three and half digits Page
The ulnar nerve supplies all the interossei and the rest of the hand muscles.
245
03. A motor cyclist involved in a road traffic accident sustained an injury to the brachial plexus on the
right side. He is found to have weakness of right shoulder abduction and forearm flexion, as well as some
sensory loss over the lateral aspect of his upper arm. The right biceps and brachioradialis reflexes are
absent. What is the likely level of maximal plexus injury? Single best answer question – choose ONE true
option only.
C4,5 root« YOUR ANSWER
C5,6 root« CORRECT ANSWER
C6,7 root
C7,8 root
C8, T1 root.
A C5/C6 lesion, Erb‟s palsy, produces sensory loss over the lateral aspect of the upper arm (deltoid
paralysis), with loss of shoulder abduction, and paralysis of the biceps, brachialis and coracobrachialis.
In addition to loss of elbow flexion, the biceps is also a powerful supinator of the forearm, so the forearm
assumes a pronated position. A T1 lesion produces a claw hand, (Klumke‟s palsy). Sympathetic chain
injury results in a Horner‟s syndrome, with ptosis of the upper eyelid and constriction of the pupil
(meiosis) on the affected side.
04. An 82-year-old woman with atrial fibrillation develops a sudden arterial occlusion of her right arm due
to a brachial embolism. Which statement pertaining to the arterial system of the upper limb best accords
with usual clinical findings? Single best answer question – choose ONE true option only.
The brachial artery bifurcates into the ulnar and radial arteries just below the level of the elbow crease«
YOUR ANSWER (Correct)
The brachial artery is crossed by the median nerve immediately above the elbow
A large single brachial vein accompanies the artery on its medial side
Profunda brachii arises from the brachial artery a hand‟s breadth above the elbow
A brachial artery embolus is especially serious because of the poor collateral circulation around the elbow
joint.
The median nerve crosses from medial to lateral at the mid-humerus. The artery is accompanied by two
vena comitantes and gives off its profunda branch near the upper end of the humeral shaft, where it
accompanies the radial nerve. As with all joints, there is an excellent circulation around the elbow joint.
-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Dr Mohammed Shamsul Islam Khan, Medical Officer, Clinical Neuro-Surgery, National Institute of Neuro-Sciences and Hospital
Sher-E-Bangla Nagar, Dhaka-1207, Bangladesh. Mobile: +880 1713 455 662, E-mail:
, MyPasTest: MRCS A Online - Jan Exam 2015
04. Anatomy; Upper limb & Breast (120Qs)
----------------------------------------------------------------------------------------------------------------------------------
05. A 38-year-old builder‟s labourer sustained a severe fracture of his left elbow, which damaged the ulnar
nerve behind the medial epicondyle of the humerus. A month later, he still has a total ulnar nerve
paralysis. Which clinical sign is most likely to be present on examination? Single best answer question –
choose ONE true option only.
Sensory loss over the ulnar 3½ digits on the ulnar side of the hand« YOUR ANSWER
Inability to grip a sheet of paper between his fingers when the hand is placed flat on the table« CORRECT
Page
ANSWER 246
Excessive sweating over the ulnar border of the left hand
Index and middle fingers on the affected side are held in the claw position
Marked wasting of the thenar eminence.
The ulnar nerve (usually) supplies sensation to the skin of the fifth and the ulnar side of the fourth finger,
front and back. Injury to the ulnar nerve may result in sympathetic interruption, with absence of sweating
in the affected area. The thenar muscles are supplied by the median nerve and are therefore spared.
Although the fourth and fifth digits are held in the clawed position when the nerve is injured at the wrist, a
high lesion paralyses the long flexors to these two fingers and results in the loss of this sign. A test for
paralysis of the palmar interossei, supplied by the ulnar nerve, is the inability to adduct the fingers and
thus to be unable to grip a sheet of paper between them.
06. An anaesthetist performs a successful block of the median nerve at the elbow. Which neurological
sign is likely to be present on examination? Single best answer question – choose ONE true option only.
Inability to flex the fingers« YOUR ANSWER
An obvious wrist drop deformity
The palm of the hand is totally anaesthetised
Inability to abduct and adduct the fingers
Loss of sensation over thenar eminence« CORRECT ANSWER.
The median nerve supplies all the muscles in the anterior compartment of the forearm, apart from the
flexor carpi ulnaris and the ulnar half of the flexor digitorum profundus; so the little and ring fingers can
still be flexed. The radial nerve supplies the extensors – hence no wrist drop.
The ulnar nerve supplies the skin of the ulnar side of the hand, hence no anaesthesia there. It also
supplies the interossei muscles of the hand, which effect abduction and adduction of the fingers.
Absence of thumb abduction, due to paralysis of abductor pollicis brevis, is a good test for median nerve
paralysis.
07. A 78-year-old man had poliomyelitis as a child, which left him with total paralysis of the left deltoid
muscle. Which feature is most likely to be present on clinical examination? Single best answer question –
choose ONE true option only.
Anaesthesia over the „epaulette‟ region of the left shoulder« YOUR ANSWER
The acromion process of the scapula forms the most lateral bony landmark of the left shoulder
-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Dr Mohammed Shamsul Islam Khan, Medical Officer, Clinical Neuro-Surgery, National Institute of Neuro-Sciences and Hospital
Sher-E-Bangla Nagar, Dhaka-1207, Bangladesh. Mobile: +880 1713 455 662, E-mail:
, MyPasTest: MRCS A Online - Jan Exam 2015
04. Anatomy; Upper limb & Breast (120Qs)
----------------------------------------------------------------------------------------------------------------------------------
Drooping of the left shoulder compared to the right side
Detectable weakness in drawing the arm forward and internally rotating the shoulder when this is compared
with the right side« CORRECT ANSWER
Full abduction of the shoulder can be achieved by the action of the intact supraspinatus muscle on the left
side. Page
Even if the supraspinatus is fully functional, it is far too weak a muscle to be able to abduct the whole 247
weight of the arm. The deltoid, in addition to being the powerful abductor of the humerus, also assists in
flexion and medial rotation (and extension and lateral rotation) of the shoulder by means of its anterior
and posterior fibres, respectively. Weakness of these movements compared to the normal side can be
detected on careful examination.
08. A 28-year-old man, who is a keen bodybuilder, presents with a short history of left upper limb
discomfort and difficulty in moving his shoulder. On examination he is noticed to have winging of the left
scapula. There is no wasting of the shoulder girdle muscles. With stabilisation of the scapula, he has a
full range of movement and is able to elevate the shoulder. Sensory testing is normal, as are upper limb
reflexes. What is the likely anatomical origin of his problem? Single best answer question – choose ONE
true option only.
C3,4 nerve root« YOUR ANSWER
Long thoracic nerve« CORRECT ANSWER
Diffuse left brachial plexus injury
Spinal accessory nerve (cranial nerve XI)
C5,6 nerve root.
Seven muscles attach the scapula (shoulder blade) to the chest wall and help maintain normal scapular
control. These muscles are trapezius, levator scapulae, rhomboids major, rhomboids minor, pectoralis
minor, omohyoid and serratus anterior. The latissimus dorsi has a small attachment at the base of the
scapula but does not significantly contribute to scapular stability.
Of these muscles, the serratus anterior and the trapezius are the most important. A winging scapula is
nearly always associated with partial or complete paralysis of either of these muscles. Weakness or
paralysis of the serratus anterior, secondary to palsy of the long thoracic nerve, is the commonest cause
of winging.
The long thoracic nerve (origin C5,6 motor roots, with sometimes a contribution from C4 +/- C7) is thin,
fragile and runs an anatomical course in the neck and upper thorax that makes it susceptible to damage
by compression or trauma. Commoner causes include: surgery (e.g. radical mastectomy, lymph node
biopsy from axilla); stretch injury during sports (as in this case); viral/ post-infectious (brachial neuritis);
other causes of neuropathy (vascular, toxic etc.).
Accessory nerve (XI) damage can also produce scapular winging via weakness of trapezius, but this
would be milder and would be expected to be associated with weakness of shoulder elevation, which this
-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Dr Mohammed Shamsul Islam Khan, Medical Officer, Clinical Neuro-Surgery, National Institute of Neuro-Sciences and Hospital
Sher-E-Bangla Nagar, Dhaka-1207, Bangladesh. Mobile: +880 1713 455 662, E-mail:
04. Anatomy; Upper limb & Breast (120Qs)
----------------------------------------------------------------------------------------------------------------------------------
01. Theme: Radial nerve injury
A Compression at the elbow
B Fracture of the mid-humerus
C Axillary compression
D Laceration at the wrist.
For each of the scenarios below describe the level of injury. Pick the most appropriate option from the
Page
above list. Each option may be used once only, more than once or not at all. 244
Scenario 1
A 25-year-old man presenting with weakness of the wrist and hand with paralysis of the triceps muscle and an
absent triceps reflex.
A - Compression at the elbow« YOUR ANSWER
C - Axillary compression« CORRECT ANSWER
In very high lesions, the radial nerve may be compressed in the axilla, eg crutch palsy.
Scenario 2
A 25-year-old man presenting with a wrist drop with inability to extend the metacarpophalangeal joints together
with paraesthesia of the skin over the anatomical snuffbox.
B - Fracture of the mid-humerus« CORRECT ANSWER
In high lesions with fractures of the humerus or due to prolonged tourniquet pressure, there is weakness
of the radial extensors of the wrist and numbness over the anatomical snuffbox. In comparison to low
radial nerve deficits, which include loss of digital extension and thumb extension, high radial nerve
deficits also result in loss of wrist extension.
Scenario 3
A 25-year-old man presenting with failure of extension of the metacarpophalangeal joints with weakness of thumb
extension and interphalangeal extension.
C - Axillary compression« YOUR ANSWER
A - Compression at the elbow« CORRECT ANSWER
In low radial nerve lesions, ie those due to fractures or dislocations at the elbow, the posterior
interosseus nerve may be injured and the patient is unable to perform finger extension with weakness of
thumb abduction and extension. In comparison to low radial nerve deficits (i.e. posterior interosseus
nerve palsy), which include loss of digital extension and thumb extension, high radial nerve deficits also
result in loss of wrist extension.
02. Which one of the following muscles in the hand is supplied by the median nerve? Single best answer
question – choose ONE true option only.
Radial two interossei« YOUR ANSWER
Abductor pollicis brevis« CORRECT ANSWER
Ulnar two lumbricales
Adductor pollicis
-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Dr Mohammed Shamsul Islam Khan, Medical Officer, Clinical Neuro-Surgery, National Institute of Neuro-Sciences and Hospital
Sher-E-Bangla Nagar, Dhaka-1207, Bangladesh. Mobile: +880 1713 455 662, E-mail:
, MyPasTest: MRCS A Online - Jan Exam 2015
04. Anatomy; Upper limb & Breast (120Qs)
----------------------------------------------------------------------------------------------------------------------------------
Extensor pollicis.
The median nerve supplies the following structures in the hand:
The abductor pollicis brevis, flexor pollicis brevis, opponens pollicis
The radial two lumbricales
The palmar surface of the radial three and half digits Page
The ulnar nerve supplies all the interossei and the rest of the hand muscles.
245
03. A motor cyclist involved in a road traffic accident sustained an injury to the brachial plexus on the
right side. He is found to have weakness of right shoulder abduction and forearm flexion, as well as some
sensory loss over the lateral aspect of his upper arm. The right biceps and brachioradialis reflexes are
absent. What is the likely level of maximal plexus injury? Single best answer question – choose ONE true
option only.
C4,5 root« YOUR ANSWER
C5,6 root« CORRECT ANSWER
C6,7 root
C7,8 root
C8, T1 root.
A C5/C6 lesion, Erb‟s palsy, produces sensory loss over the lateral aspect of the upper arm (deltoid
paralysis), with loss of shoulder abduction, and paralysis of the biceps, brachialis and coracobrachialis.
In addition to loss of elbow flexion, the biceps is also a powerful supinator of the forearm, so the forearm
assumes a pronated position. A T1 lesion produces a claw hand, (Klumke‟s palsy). Sympathetic chain
injury results in a Horner‟s syndrome, with ptosis of the upper eyelid and constriction of the pupil
(meiosis) on the affected side.
04. An 82-year-old woman with atrial fibrillation develops a sudden arterial occlusion of her right arm due
to a brachial embolism. Which statement pertaining to the arterial system of the upper limb best accords
with usual clinical findings? Single best answer question – choose ONE true option only.
The brachial artery bifurcates into the ulnar and radial arteries just below the level of the elbow crease«
YOUR ANSWER (Correct)
The brachial artery is crossed by the median nerve immediately above the elbow
A large single brachial vein accompanies the artery on its medial side
Profunda brachii arises from the brachial artery a hand‟s breadth above the elbow
A brachial artery embolus is especially serious because of the poor collateral circulation around the elbow
joint.
The median nerve crosses from medial to lateral at the mid-humerus. The artery is accompanied by two
vena comitantes and gives off its profunda branch near the upper end of the humeral shaft, where it
accompanies the radial nerve. As with all joints, there is an excellent circulation around the elbow joint.
-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Dr Mohammed Shamsul Islam Khan, Medical Officer, Clinical Neuro-Surgery, National Institute of Neuro-Sciences and Hospital
Sher-E-Bangla Nagar, Dhaka-1207, Bangladesh. Mobile: +880 1713 455 662, E-mail:
, MyPasTest: MRCS A Online - Jan Exam 2015
04. Anatomy; Upper limb & Breast (120Qs)
----------------------------------------------------------------------------------------------------------------------------------
05. A 38-year-old builder‟s labourer sustained a severe fracture of his left elbow, which damaged the ulnar
nerve behind the medial epicondyle of the humerus. A month later, he still has a total ulnar nerve
paralysis. Which clinical sign is most likely to be present on examination? Single best answer question –
choose ONE true option only.
Sensory loss over the ulnar 3½ digits on the ulnar side of the hand« YOUR ANSWER
Inability to grip a sheet of paper between his fingers when the hand is placed flat on the table« CORRECT
Page
ANSWER 246
Excessive sweating over the ulnar border of the left hand
Index and middle fingers on the affected side are held in the claw position
Marked wasting of the thenar eminence.
The ulnar nerve (usually) supplies sensation to the skin of the fifth and the ulnar side of the fourth finger,
front and back. Injury to the ulnar nerve may result in sympathetic interruption, with absence of sweating
in the affected area. The thenar muscles are supplied by the median nerve and are therefore spared.
Although the fourth and fifth digits are held in the clawed position when the nerve is injured at the wrist, a
high lesion paralyses the long flexors to these two fingers and results in the loss of this sign. A test for
paralysis of the palmar interossei, supplied by the ulnar nerve, is the inability to adduct the fingers and
thus to be unable to grip a sheet of paper between them.
06. An anaesthetist performs a successful block of the median nerve at the elbow. Which neurological
sign is likely to be present on examination? Single best answer question – choose ONE true option only.
Inability to flex the fingers« YOUR ANSWER
An obvious wrist drop deformity
The palm of the hand is totally anaesthetised
Inability to abduct and adduct the fingers
Loss of sensation over thenar eminence« CORRECT ANSWER.
The median nerve supplies all the muscles in the anterior compartment of the forearm, apart from the
flexor carpi ulnaris and the ulnar half of the flexor digitorum profundus; so the little and ring fingers can
still be flexed. The radial nerve supplies the extensors – hence no wrist drop.
The ulnar nerve supplies the skin of the ulnar side of the hand, hence no anaesthesia there. It also
supplies the interossei muscles of the hand, which effect abduction and adduction of the fingers.
Absence of thumb abduction, due to paralysis of abductor pollicis brevis, is a good test for median nerve
paralysis.
07. A 78-year-old man had poliomyelitis as a child, which left him with total paralysis of the left deltoid
muscle. Which feature is most likely to be present on clinical examination? Single best answer question –
choose ONE true option only.
Anaesthesia over the „epaulette‟ region of the left shoulder« YOUR ANSWER
The acromion process of the scapula forms the most lateral bony landmark of the left shoulder
-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Dr Mohammed Shamsul Islam Khan, Medical Officer, Clinical Neuro-Surgery, National Institute of Neuro-Sciences and Hospital
Sher-E-Bangla Nagar, Dhaka-1207, Bangladesh. Mobile: +880 1713 455 662, E-mail:
, MyPasTest: MRCS A Online - Jan Exam 2015
04. Anatomy; Upper limb & Breast (120Qs)
----------------------------------------------------------------------------------------------------------------------------------
Drooping of the left shoulder compared to the right side
Detectable weakness in drawing the arm forward and internally rotating the shoulder when this is compared
with the right side« CORRECT ANSWER
Full abduction of the shoulder can be achieved by the action of the intact supraspinatus muscle on the left
side. Page
Even if the supraspinatus is fully functional, it is far too weak a muscle to be able to abduct the whole 247
weight of the arm. The deltoid, in addition to being the powerful abductor of the humerus, also assists in
flexion and medial rotation (and extension and lateral rotation) of the shoulder by means of its anterior
and posterior fibres, respectively. Weakness of these movements compared to the normal side can be
detected on careful examination.
08. A 28-year-old man, who is a keen bodybuilder, presents with a short history of left upper limb
discomfort and difficulty in moving his shoulder. On examination he is noticed to have winging of the left
scapula. There is no wasting of the shoulder girdle muscles. With stabilisation of the scapula, he has a
full range of movement and is able to elevate the shoulder. Sensory testing is normal, as are upper limb
reflexes. What is the likely anatomical origin of his problem? Single best answer question – choose ONE
true option only.
C3,4 nerve root« YOUR ANSWER
Long thoracic nerve« CORRECT ANSWER
Diffuse left brachial plexus injury
Spinal accessory nerve (cranial nerve XI)
C5,6 nerve root.
Seven muscles attach the scapula (shoulder blade) to the chest wall and help maintain normal scapular
control. These muscles are trapezius, levator scapulae, rhomboids major, rhomboids minor, pectoralis
minor, omohyoid and serratus anterior. The latissimus dorsi has a small attachment at the base of the
scapula but does not significantly contribute to scapular stability.
Of these muscles, the serratus anterior and the trapezius are the most important. A winging scapula is
nearly always associated with partial or complete paralysis of either of these muscles. Weakness or
paralysis of the serratus anterior, secondary to palsy of the long thoracic nerve, is the commonest cause
of winging.
The long thoracic nerve (origin C5,6 motor roots, with sometimes a contribution from C4 +/- C7) is thin,
fragile and runs an anatomical course in the neck and upper thorax that makes it susceptible to damage
by compression or trauma. Commoner causes include: surgery (e.g. radical mastectomy, lymph node
biopsy from axilla); stretch injury during sports (as in this case); viral/ post-infectious (brachial neuritis);
other causes of neuropathy (vascular, toxic etc.).
Accessory nerve (XI) damage can also produce scapular winging via weakness of trapezius, but this
would be milder and would be expected to be associated with weakness of shoulder elevation, which this
-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Dr Mohammed Shamsul Islam Khan, Medical Officer, Clinical Neuro-Surgery, National Institute of Neuro-Sciences and Hospital
Sher-E-Bangla Nagar, Dhaka-1207, Bangladesh. Mobile: +880 1713 455 662, E-mail:
