Lesions to Plexus

Question 1

Erb Duchenne

Answer 1

Lesion to C5 C6 roots
Impacts the anterior and posterior divisions of the upper trunk
Mainly the axillary, musculocutaneous, and suprascapular nerves - other upper trunk nerves would be impacted as well

Question 2

Erb Duchenne Symptoms

Answer 2

Paralysis of abductors and lateral rotators of shoulder –> loss of suprascapular and axillary
Paralysis of elbow flexors and forearm supinators –> loss of musculocutaneous

Question 3

Erb Duchenne Clinical Appearance

Answer 3

Waiters Tip
Loss and wasting of deltoid muscle - arm hangs at side
Internal rotation of arm
Pronation at forearm (loss of biceps)
Sensory loss at shoulder and lateral arm and forearm (loss of C5 and C6 dermatomes

Question 4

Klumpkes Paralysis

Answer 4

Lesion C8-T1

Impacts lower trunk, loss of ulnar nerve and weakness in median nerve

Question 5

Klumpkes Symptoms

Answer 5

Loss to intrinsic muscles of hand and weakness/loss to the extrinsic hand flexors, especially those innervated by the ulnar nerve

Question 6

Klumpkes Clinical Appearance

Answer 6

Claw hand
Loss and weakness of ulnar forearm flexors, pronators, and all intrinsic hand muscles
Muscle wasting, especially flexor carpi ulnaris, ulnar half of flexor digitorum profundus, and all intrinsic hand muscles
Arm supination and wrist extension
Hand in full claw position
Sensory loss to medial forearm and hand (C8-T1 dermatomes)

Question 7

What might Klumples be accompanied by

Answer 7

Horner’s syndrome from loss of connection from T1 sympathetics to sympathetic chain

• Miosis = pupil constriction
• Ptosis = drooping eyelid
• Anahydrosis = lack of sweat on affected side

Question 8

Radial Nerve Palsy - lesion in axilla or proximal arm

Answer 8

Lesion in axilla or proximal arm - Saturday night palsy
Impact = generally from compression of the radial nerve in radial groove of humerous, can also be caused by humeral shaft fracture

Question 9

Symptoms of Radial Nerve Palsy - lesion in axilla or proximal arm

Answer 9

Some weakness in triceps, loss of all muscles in posterior compartment of forearm (wrist and finger extensors)
Possible sensory loss to posterior cutaneous nerve of forearm (test at dorsum of hand btw thumb and index)

Question 10

Clinical appearance of Radial nerve palsy - lesion n axilla of proximal arm

Answer 10

Wrist drop - inability to extend the wrist and the fingers at the MCP
The relaxed wrist assumes a flexed position because of tonus of antagonists (flexors)

Question 11

Radial Nerve Palsy - lesion in forearm

Answer 11

Impact from trauma to forearm

Symptoms = inability to extend thumb and MCP joints due to damage to deep branch of radial nerve

Question 12

Radial nerve palsy - lesion at wrist

Answer 12

Handcuff palsy
Impact from compression of superficial branch of radial nerve at wrist
Symptoms = paresthesia or numbness over dorsum of hand Mc I and II

Question 13

Median Nerver Palsy

Answer 13

Lesion median nerve

Impact varies depending on where along median nerve the lesion occurs (at elbow, carpal tunnel, or in between)

Question 14

Symptoms of Median Nerve Palsy

Answer 14

Muscle weakness loss for those innervated by median nerve below the lesion
Might cause sensory loss to anterior lateral hand

Question 15

Pronator syndrome

Answer 15

impingement on median nerve as it passes between the two heads of pronator teres

Question 16

Clinical Appearance of Median Nerve Palsy - sign of benediction

Answer 16

inability to flex distal interphalangeal joint of the lateral three digits and flex these digits into a fist - ask patient to make a tight fist and they can’t flex MCP and IP joints of digits 1-3

Question 17

Clinical Appearance of Median Nerve Palsy - simian hand

Answer 17

wasting of thenar eminence, thumb adducted and laterally rotated due to loss of thenar muscles
This presentation is also often seen in sign of benediction
When it is NOT accompanied by deficits to long flexors of the thumb and laeral digits it suggests loss of the median nerve at the carpal tunnel

Question 18

Clinical appearance of medial nerve palsy - OK sign

Answer 18

Inability to make the sign
When not accompanied by sensory deficits of the thenar muscles, it indicated impingement of anterior interosseous nerve only

Question 19

Ulnar Nerve Palsy

Answer 19

Lesion at ulnar nerve
Impact - most frequent where ulnar nerve passes the medial epicondyle of the humerus but impact varies depending on where lesion is

Question 20

Symptoms of ulnar nerve palsy

Answer 20

Muscle weakness/loss for those innervated by ulnar nerve below lesion

Question 21

Clinical appearance of ulnar nerve damage

Answer 21

Ulnar claw
The MCP 4 and 5 joints become hyperextended with the IP joints flexed
PASSIVE clinical sign
Abduction/Adduction will be compromised
Can include atrophy of first dorsal interosseous muscle and possible sensation loss to medial hand