Nerve injuries and consequences in the upper limb

Question 1

Which nerves supply the shoulder muscles and elbow joint flexors?

Answer 1

C5+C6

Question 2

Which nerves supply the elbow extensors?

Answer 2

C7+C8

Question 3

Which nerves are responsible for coarse wrist and hand movements?

Answer 3

C6-C8

Question 4

Which nerves supply small muscles of the hand (fine movements)?

Answer 4

C8+T1

Question 5

Which rami for superior trunk

Answer 5

C5-6

Question 6

Which rami form middle trunk

Answer 6

C7

Question 7

Which rami form inferior trunk

Answer 7

C8 T1

Question 8

How does each trunk divide

Answer 8

Into a posterior and anterior division

Question 9

What forms lateral chord

Answer 9

Anterior branches of superior and middle trunks

Question 10

What forms posterior chord

Answer 10

All 3 posterior divisions of chord

Question 11

What forms medial chord

Answer 11

Anterior branch of inferior trunk

Question 12

How are chords named

Answer 12

On position to axillary artery

Question 13

Why is dermatome vs cutaneous nerve pattern so different

Answer 13

The recombination of fibres in the plexus

Question 14

What does axillary nerve come off

Answer 14

Posterior chord

Question 15

Route of axillary nerve

Answer 15

Passes posterior to axillary artery then becomes lateral before going behind shoulder joint

Question 16

How is axillary nerve commonly damaged

Answer 16

Dislocation of shoulder and fracture of surgical neck of humerus

Question 17

Supply of axillary nerve

Answer 17

Deltoid

Teres minor

Question 18

Effects of axillary nerve damage

Answer 18

Atrophy of deltoid

Question 19

Branch of axillary nerve

Answer 19

Superior lateral cutaneous nerve of arm

Useful in axillary nerve assessment

Question 20

Where does superior lateral cutaneous nerve of arm supply

Answer 20

Superior lateral humerus area of skin

Question 21

How to assess axillary nerve damage

Answer 21

Wasting of deltoid

Sensory innervation of superior lateral arm

Question 22

Path of radial nerve

Answer 22

Passes into posterior compartments of arm and forearm

Question 23

How can radial nerve be easily damaged

Answer 23

Fracture of humerus as runs very close to it in radial groove

Question 24

Effects of radial nerve damage

Answer 24

Wrist drop off as lose extension ability in forearm
Anaesthesia of lateral dorsal hand
Wasting of posterior forearm muscles
Loss of power grip

Question 25

How do you lose power grip in radial nerve damage

Answer 25

You need extensors to exert maximal grip as if not flexors have to do too much work

Question 26

Where does musculocutaneous nerve branch off

Answer 26

Lateral chord

Question 27

Route of musculocutaneous nerve

Answer 27

Goes through coracobrachioradialis muscle to supply anterior arm muscles with a cutaneous branch supplying the lateral side of the forearm and lower arm

Question 28

How is musculocutaneous nerve damaged

Answer 28

Not damaged in trauma as well protected by muscle but is easily damaged in breast cancer surgery due to its proximity to lymph nodes

Question 29

Path of ulnar nerve

Answer 29

Comes off medial chord in the axilla and continues down the medial side of the arm behind medial humeral epicondyle then down the medial forearm to muscles of hand

Question 30

Common sites of injury to ulnar nerve

Answer 30

Behind medial epicondyle | Ulnar side of wrist in a lot of cases due to self harm

Question 31

Muscles supplied by ulnar nerve in forearm

Answer 31

Flexor carpi ulnaris | Medial half to digits 4,5 of flexor digitorum profundus

Question 32

Muscles supplied by ulnar nerve in hand

Answer 32

``` Palmaris brevis Hypothenar muscles All interossei Adductor pollicis Lumbricals 4 and 5 ```

Question 33

Signs of injury to ulnar nerve

Answer 33

Claw deformity as lumbrical muscles for digits 4 and 5

Question 34

What is the ulnar paradox

Answer 34

Clawing deformity is much worse in injury to ulnar nerve at elbow as ulnar nerve also innervates medial half of FDP which if injured at wrist isn’t affected

Question 35

Route of median nerve

Answer 35

Comes from lateral and medial chords and passes medially down anterior portion of arm over elbow joint to medial aspect of forearm through carpal tunnel

Question 36

Branches of median nerve after coming out of carpal tunnel

Answer 36

One to hypothenar muscles | Then sensory ones to all digits except medial half of ring finger and little finger

Question 37

Signs of carpal tunnel syndrome

Answer 37

Wasting of hypothenar muscles so loss of hypothenar muscle | Loss of sensation and fine movement in lateral digits

Question 38

Supply of long thoracic nerve

Answer 38

Serratus anterior

Question 39

How is long thoracic nerve easily damaged

Answer 39

Very superficial so any trauma will damage it

Question 40

Signs of damage to long thoracic nerve

Answer 40

When you press against a wall the scapula will move up in a movement called winging as serratus anterior has role in holding scapula in place

Question 41

Name of injury to upper root

Answer 41

Erb duchenne palsy

Question 42

How are upper roots damaged

Answer 42

Over stretching of neck in fall and also in child birth

Question 43

Sign of upper root injury

Answer 43

“Waiters tip” position where forearm pronated and unopposed flexion as lack of biceps innervation

Question 44

Lower root nerve injury name

Answer 44

Klumpkes palsy | In particular T1 but also C8

Question 45

Cause of klumpkes palsy

Answer 45

Over abduction due to for example gripping overhead to break a fall Childbirth

Question 46

Lower root injury signs

Answer 46

T1 mainly supplies small muscles of hand via ulnar and median nerve so hand becomes very clawed

Question 47

Hierarchal order to brachial plexus anatomically

Answer 47

Rami Tunks Divisions Cords

Question 48

Which rami form long thoracic nerve

Answer 48

C5-7

Question 49

Nerves which make up brachial plexus

Answer 49

C5-T1