UL1 - Clinical

Question 1

which nerve is commonly affected in a surgical neck fracture of the humerus?

Answer 1

axillary nerve

Question 2

what structures are at risk in a surgical neck fracture of the humerus?

Answer 2

axillary nerve
posterior circumflex humeral arteries

Question 3

sensory and motor consequences of damage to the axillary nerve?

Answer 3

motor damage - weakness/ paralysis of the deltoid muscle, causes difficulty with arm abduction

sensory damage - reduced sensation in the regimental badge area (superolateral aspect of the arm)

Question 4

what structures are at risk in a mid-shaft humerus fracture?

Answer 4

radial nerve
profunda brachii artery

Question 5

sensory and motor consequences of damage to the radial nerve?

Answer 5

sensory damage - reduced sensation in the posterior arm, forearm, and hand

motor damage - wrist drop due to paralysis of wrist extensors

Question 6

why may wrist drop occur following a mid-shaft humerus fracture?

Answer 6

damage to the radial nerve can cause paralysis of wrist extensors - leads to wrist drop

Question 7

in what type of humerus fracture may reduced sensation in the regimental badge area occur?

Answer 7

surgical neck fracture of the humerus

Question 8

what nerve is at risk in a distal humeral fracture?

Answer 8

median nerve

Question 9

what nerve is at risk with an avulsion fracture of the medial epicondyle?

Answer 9

ulnar nerve

Question 10

clinical (sensory & motor) consequences of an avulsion fracture of the medial epicondyle?

Answer 10

motor damage - weakness in muscles innervated by the ulnar nerve (e.g. intrinsic hand muscles)

sensory damage - reduced sensation along the ulnar aspect of the hand and forearm

Question 11

what is the characteristic motor deficit of a radial nerve injury in a mid-shaft humerus fracture?

Answer 11

wrist drop due to paralysis of wrist extensors

Question 12

(!!) describe the motor functional implications of an avulsion fracture of the medial epicondyle, and why

Answer 12

weakness or paralysis in intrinsic hand muscles as they’re innervated by the ulnar nerve - can reduce grip strength

Question 13

(!!) how does the anatomical location of the radial nerve in the radial groove contribute to the specific deficits seen in a mid-shaft humerus fracture?

Answer 13

the radial nerve spirals along the radial groove of the humerus - it’s vulnerable to damage in fractures of the mid-shaft

this can lead to:
- wrist drop due to paralysed/damaged wrist extensors
- reduced sensation in the posterior arm, forearm and hand

Question 14

where is sensation often reduced/ affected with mid-shaft humeral fractures?

Answer 14

posterior arm, forearm and hand

Question 15

An 84-year-old man injures his arm while skiing. An x-ray film taken in the emergency department indicates a fracture that has displaced the greater tubercle of the humerus. Movements of the humerus most likely affected by this injury would include which of the following?

Answer 15

abduction & lateral rotation

Question 16

A 32-year-old woman undergoes a right mastectomy for cancer. After her operation, she complains to her physician that when she pushes her arms against the wall her right scapula protrudes posteriorly away from the thoracic wall. Injury to which of the following nerves would most likely cause this problem?

Answer 16

long thoracic nerve

Question 17

anteroinferior dislocations are the most common type of shoulder dislocation - how do they happen? what structures are at risk?

Answer 17

mechanism: excessive extension/ lateral rotation - e.g. falling on an outstretched arm

structures at risk:
- axillary & musculocutaneous nerves of brachial plexus

Question 18

Erb’s palsy is most commonly due to injury of which part of the brachial plexus?
A. Roots C8–T1
B. Upper trunk (C5–C6)
C. Posterior cord
D. Lateral cord

Answer 18

B. Upper trunk (C5–C6)

Question 19

Which nerve is not typically affected in Erb’s palsy?
A. Suprascapular
B. Axillary
C. Musculocutaneous
D. Ulnar

Answer 19

D. Ulnar (Ulnar is C8–T1 - lower trunk injury (like in Klumpke’s palsy))

Question 20

The characteristic “waiter’s tip” posture in Erb’s palsy is due to:
A. Flexed elbow and supinated forearm
B. Extended elbow, pronated forearm, adducted and medially rotated arm
C. Extended wrist and hyperflexed fingers
D. Claw hand deformity

Answer 20

B. Extended elbow, pronated forearm, adducted and medially rotated arm

Question 21

A new-born presents with loss of shoulder abduction and elbow flexion on one side after a difficult delivery. Which of the following muscles is most likely still functioning normally?
A. Supraspinatus
B. Deltoid
C. Triceps brachii
D. Biceps brachii

Answer 21

C. Triceps brachii - innervated by the radial nerve (C6–T1), and usually spared in upper trunk injuries (also has an extensor function)

Question 22

which nerve roots are affected in Erb’s palsy?

Answer 22

C5-6

Question 23

what is the characteristic sign of Erb’s palsy?

Answer 23

‘waiter’s tip’ = arm adducted, medially rotated, elbow extended, forearm pronated

Question 23

Characteristic sign of Klumpke’s palsy?

Answer 23

claw hand - hyperflexed medial fingers, impaired MCP and IP control (lumbrical weakness)

Question 24

Klumpke’s palsy is associated with injury to which nerve roots?

Answer 24

C8-T1 (lower trunk)

Question 24

what causes Erb's palsy?

Answer 24

difficult childbirth/delivery - leads to excessive pulling of baby's neck and shoulder

Question 24

Winging of the scapula is due to injury of which nerve? A. Axillary B. Radial C. Long thoracic D. Thoracodorsal

Answer 24

C. Long thoracic

Question 24

A patient falls and grabs a ledge to break the fall. He develops claw hand. Which of the following is the most likely diagnosis? A. Erb’s palsy B. Radial nerve injury C. Klumpke’s palsy D. Median nerve palsy

Answer 24

C. Klumpke’s palsy

Question 25

What movement is weakened by axillary nerve injury and what is a common cause?

Answer 25

shoulder abduction = deltoid weakness common for surgical neck of humerus fractures

Question 25

Which nerve is compressed in the coracobrachialis muscle, leading to weak elbow flexion and sensory loss in the lateral forearm? A. Median nerve B. Axillary nerve C. Musculocutaneous nerve D. Ulnar nerve

Answer 25

C. Musculocutaneous nerve (runs through coracobrachialis)

Question 26

Which muscle is primarily affected by an axillary nerve injury? A. Infraspinatus B. Deltoid C. Supraspinatus D. Trapezius

Answer 26

B. Deltoid - affects shoulder abduction