detailed upper limb nerves

Question 1

the cutaneous innervation of axillary nerve

Answer 1

inferior region of deltoid

Question 2

common cause of axillary nerve injury

Answer 2

shoulder dislocation - because of nerve’s proximity to joint

Question 3

what are the effects of axillary nerve injury?

Answer 3

paralysis of deltoid and teres minor –> inability to abduct arm more than actions of supraspinatus

Question 4

where is the long thoracic nerve vulnerable to entrapment

Answer 4

as it pierces medial scalene
compression against 2nd rib

Question 5

clinical signs of long thoracic nerve injury?

Answer 5

paresis (muscle weakness) in shoulder abduction and elevation
vague shoulder weakness and pain
difficulty with overhead tasks
winging of scapular
+ve wall push away test
abnormal scapular mvmt
difficulty raising arm up straight

Question 6

what is the cutaneous innervation of long thoracic nerve?

Answer 6

none - it is a purely motor nerve, innervating serratus anterior (which stabilizes scapular to posterior thorax)

Question 7

what are the nerve root origins of musculocutaneous nerve?

Answer 7

C 5,6 &7

Question 8

clinical signs & symptoms of musculocutaneous nerve (C5 - 7) entrapment syndrome in shoulder

Answer 8

biceps muscle atrophy & diminished tone
paresthesia or hyperesthesia along lateral forearm
diminished or absent biceps deep tendon reflex
typically no pain

Question 9

clinical signs & symptoms of musculocutaneous nerve (C5 - 7) entrapment syndrome in elbow

Answer 9

may mimic lateral epicondylitis
anterolateral elbow pain
lateral wrist and forearm pain and hyperesthesia
pain with elbow extension and forearm pronation
reduced pain with forearm supination

Question 10

what are the origins on the radial nerve?

Answer 10

C5, 6, 7, 8 & T1

Question 11

motor innervations of radial nerve?

Answer 11

triceps brachii
anconeus
brachioradialis
most posterior compartment extrinsic hand muscles

Question 12

what is the result of injury to radial nerve?
what is the cardinal feature to damage to radial nerve?

Answer 12

total paralysis of wrist and digit extensors - dropped wrist deformities
wrist drop

Question 13

when is radial nerve most likely to be injured?

Answer 13

fractures to humerus or direct blow to humerus

Question 14

what is the cutaneous distribution of the radial nerve?

Answer 14

Question 15

what nerve roots does the ulnar nerve arise from?

Answer 15

C7 , 8, T1

Question 16

when the ulnar nerve enters the anterior compartment of the forearm what muscles does it supply?

Answer 16

FCU and medial half of FDP

Question 17

where does the ulnar nerve divide?

Answer 17

entering the hand, divides into superficial and deep branch.
deep branch: hypothenar, intermediate hand muscle and thenar hand muscles (adductor pollicis, FPB)
superficial branch: palmaris brevis, skin on anterior and posterior hand (medial hand & 11/2 digits)

Question 18

where is the most common injury to ulnar nerve?

Answer 18

groove behind medial epicondyle by trauma or entrapment

Question 19

What are the innervations of the suprascapular nerve?

Answer 19

motor: supraspinatus & infraspinatus
cutaneous: (sensory branches) ac joint & subacromial bursa

Question 20

what are the symptoms of suprascapular nerve syndrome?

Answer 20

• posterior shoulder pain along upper traps
• nocturnal pattern with aggreva by shoulder mvmt (overhead, repetitive activities)
• pain over suprascapular notch suggests suprascapular nerve inv

Question 21

What are clinical signs and symptoms of suprascapular nerve (C5-6) syndrome?

Answer 21

• posterior shoulder pain
• AC pain
• focal pain over scapular notch
• inc night pain
• +ve crossed arm adduction test
• supraspinatus & infraspinatus atrophy
• ## paresis of sh abd & ER

Question 22

what are the clinical signs and symptoms of scapulocostal syndrome?

Answer 22

• neck pain
• upper arm & chest pain
• shoulder girdle spasm
• no sensory deficit or muscle atrophy or paralysis
• focal medial scapular border pain
• scapular elevation of chest wall with fwd stretch