Clinical conditions of the upper limb

Question 1

What can cause injuries to the upper brachial plexus?

Answer 1

• Usually result from an excessive increase in the angle between the neck and the shoulder
• May occur in trauma
• During the birth of a baby if the shoulder becomes impacted in the pelvis and excessive traction is applied to the baby’s neck

Question 2

Which parts of the upper brachial plexus gets injured?

Answer 2

• C5 and C6

Question 3

What are the signs and symptoms of upper brachial plexus injury?

Answer 3

• Sensory alteration in these dermatomes (C5 and C6) and paralysis of muscles predominantly supplied by these nerve roots

Question 4

What movements will be lost if the upper brachial plexus is injured?

Answer 4

• C5: shoulder abduction and external rotation
• C6: elbow flexion, wrist extension, supination, internal rotation of shoulder

Question 5

Which muscles are paralysed in an upper brachial plexus injury?

Answer 5

• Deltoid (axillary nerve: C5-6)
• Teres minor (axillary nerve: C5-6)
• Biceps brachii (musculocutaneous nerve: C5-7)
• Brachioradialis (radial nerve: C5-T1)
• Brachialis (musculocutaneous nerve: C5-7)
• Coracobrachialis (musculocutaneous nerve: C5-7)

Question 6

What happens as a result of upper brachial plexus injury?

Answer 6

• Limb hangs by the side in internal rotation with an adducted arm and extended elbow
• This is called the ‘waiter’s tip’ position
• Injury to the roots of the brachial plexus is called Erb’s palsy

Question 7

What can cause injuries to the lower brachial plexus?

Answer 7

• Forced hyperextension or hyperabduction e.g. someone falling from a height and grabs onto a tree branch on the way down

Question 8

What is injury to the lower roots of the brachial plexus known as?

Answer 8

• Klumpke’s palsy

Question 9

Which nerve roots are affected by injury to the lower brachial plexus?

Answer 9

• C8 and T1
• Weakness affects the following movements
• C8: finger flexion/finger extension/thumb extension
• T1: finger abduction and adduction

Question 10

What does paralysis caused by lower brachial plexus injury affect?

Answer 10

• Intrinsic muscles of the hand and flexors within the forearm that are supplied by the ulnar nerve
• Affects those muscles supplied by the C8 and T1 fibres within the median and radial nerves

Question 11

What happens if the long thoracic nerve is damaged?

Answer 11

• Winging of the scapula
• Medial border of scapula is no longer held against chest wall, so protrudes posteriorly

Question 12

How do we see winging of the scapula?

Answer 12

• Ask patient to place the palm of their hand on a wall and push
• Scapula lifts off the underlying ribs

Question 13

What causes fractures of the scapula?

Answer 13

• Relatively uncommon
• Indicate severe chest trauma
• High speed road collisions, crushing injuries, high impact sport injuries

Question 14

How do we treat a fractured scapula?

Answer 14

• Does not require fixation as tone of surrounding muscles holds fragments in place whilst healing occurs

Question 15

What causes fracture of the surgical neck of the humerus?

Answer 15

• Blunt trauma to the shoulder
• FOOSH

Question 16

Which key neurovascular structures are at risk when the surgical neck of the humerus is fractured?

Answer 16

• Axillary nerve
• Posterior circumflex artery

Question 17

What is the classical presentation of a ruptured biceps tendon?

Answer 17

• Patient reports that they heard something snap in the shoulder whilst lifting
• Characteristically, flexion of the arm at the elbow produces a firm lump in the lower part of the arm (the unopposed contracted muscle belly of the biceps)
• This is ‘Popeye sign’

Question 18

Why does the patient not notice much weakness in the upper limb following rupture of the biceps tendon?

Answer 18

• Action of the brachialis (flexion) and supinator muscles is in tact
• Management is usually conservative

Question 19

What are the symptoms of a dislocated shoulder?

Answer 19

• Visible deformation of the shoulder
• Visible swelling and/or bruising around the shoulder
• Severe restriction of movement of the shoulder

Question 20

What is the most common type of shoulder dislocation and why?

Answer 20

• Anterior (antero-inferiorly)
• Shallow glenoid fossa
• Joint is weak at its inferior aspect
• Displaces in an anterior direction due to pull of muscles

Question 21

How is the arm held following an anterior shoulder dislocation?

Answer 21

• External rotation and slight abduction

Question 22

What are the common mechanisms of anterior shoulder dislocation?

Answer 22

• Arm is abducted and externally rotated (hand behind head) and then forced posteriorly
• Or a direct blow to the posterior shoulder

Question 23

What is a Bankart lesion or labral tear?

Answer 23

• Force of humeral head popping out of the socket causes part of the glenoid labrum to be torn off
• Sometimes a small piece of bone can be torn off with the labrum

Question 24

What is a Hill-Sachs lesion?

Answer 24

• Anterior dislocation of the humeral head
• Tone of infraspinatus and teres minor means that posterior aspect of the humeral head becomes jammed against anterior lip of glenoid fossa
• Can cause a dent in the posterolateral humeral head

Question 25

What can cause posterior shoulder dislocations?

Answer 25

• Violent muscle contractions due to epileptic seizure, electrocution, lightning strike
• Blow to anterior shoulder
• Arm is flexed across body and pushed posteriorly

Question 26

How do patients usually present with posterior shoulder dislocation?

Answer 26

• Arm is internally rotated and adducted
• Patient demonstrates flattening/squaring of the shoulder with a prominent coracoid process
• Arm cannot be externally rotated into the anatomical position

Question 27

How does a posterior shoulder dislocation appear on X-ray?

Answer 27

• Light-bulb sign
• Glenohumeral distance is increased