Nerve Lesions

Question 0

Cause of injury involving C5/C6 roots or superior trunk:

Answer 0

Most often due to excessive separation of head and shoulder during a fall, accident, or botched delivery, stab/bullet wound to the neck –> results in tearing or stretching of roots/trunk (Waiter’s tip)

Question 1

Injury involving C5/C6 roots or superior trunk:

Answer 1

Waiter’s tip

Question 2

Waiter’s tip (Erb-Duchenne’s palsy) loss of which muscle movements:

Answer 2

Flexion, abduction, and lateral rotation at the shoulder joint - upper limb hangs by the side in medial rotation

Question 3

Muscles affected by Waiter’s tip (Erb-Duchenne’s palsy):

Answer 3

Deltoid, biceps, brachialis, brachioradialis, supraspinatous, teres major, subscapularis, infraspinatus, and teres minor (**infraspinatus and teres minor are chief lateral rotators of the upper limb) - all of these innervations come from C5 and C6 roots

Basically: all of the lateral rotators are out, so the medial rotators dominate and the shoulder is over rotated medially

Question 4

Injury involving the posterior cord:

Answer 4

Wrist-drop

Question 5

Cause of injury involving the posterior cord:

Answer 5

Due to poorly fitting crutches putting pressure on the radial nerve or “Saturday night palsy” when an intoxicated person hangs their arm over the back of a chair for extended periods of unconsciousness

Question 6

Wrist-drop involves which nerve?

Answer 6

Radial nerve

Question 7

Movements affected by Wrist-drop:

Answer 7

The person is unable to extend the forearm, hand or digits due to affected muscles innervated by the radial nerve

Can be accompanied by posterior hand numbness– superficial nerve of brachii

Question 8

Injury involving the inferior trunk:

Answer 8

Ulnar nerve damage - Claw Hand

Question 9

Cause of injury involving inferior trunk:

Answer 9

Results from sudden upward pulling of the upper limb, may also arise due to cervical rib or pulmonary carcinoma; the inferior trunk of the brachial plexus (C8/T1) is involved and usually affects ulnar nerve function (severe motor and sensory loss to hand)

Question 10

Claw hand:

Answer 10

Resulting imbalance of flexion/extension which occurs at the MP and IP joints, in addition to being unable to abduct or adduct digits 2-5 (loss of interossei), the patient presents with hyperextended MP joints of digits 4-5 and somewhat flexed IP joints (loss of lumbricals 4-5) - patient has difficulty making a fist since the flexor digitorum profundus to digits 4-5 is affected

Question 11

Long thoracic nerve damage:

Answer 11

Winged scapula: axillary trauma, pt. cannot hold scapula against thorax wall when asked to push against a wall, cannot fully abduct upper limb on affected side because scapula cannot be rotated

Question 12

Musculocutaneous nerve damage:

Answer 12

If injured within the axilla, weakness of upper limb flexion and severe weakness of forearm flexion, weakness when supinating the forearm from a partially flexed position (biceps involved)

Question 13

Upper Radial nerve damage:

Answer 13

Due to fractured humerus while in the radial groove - little loss of forearm extension but wrist drop does occur

Question 14

Lower Radial nerve damage:

Answer 14

If lesioned at the neck of the radius (deep radial nerve), wrist drop is not as severe since extensor carpi radialis longus and brevis are spared but still have loss of digital extension of proximal phalanges and thumb impairments

Question 15

Median nerve damage:

Answer 15

If injured in axilla or arm –> loss of forearm pronation, diminished hand and digital flexion, wasting of thenar eminence, loss of palmar and digital sensation and loss of sweating on the lateral palm

Question 16

Hand of Benediction:

Answer 16

Median nerve damage - Pronator Teres or Anterior Interosseous Syndrome - entrapment of anterior interosseous nerve as it exits the pronator teres, loss of deep compartment muscles

Question 17

Carpal Tunnel Syndrome:

Answer 17

Median nerve damaged, will result in thenar eminence wasting and loss of sensation

Question 18

Testing for Nerve Damage:

Answer 18

= Dermatomes

Sensory loss and motor loss

Question 19

Sensory loss - C5:

Answer 19

Lateral side of cubital fossa

Question 20

Sensory loss - C6:

Answer 20

Thumb (superficial radial n)

Question 21

Sensory loss - C7:

Answer 21

Middle finger (median n)

Question 22

Sensory loss - C8:

Answer 22

Minimal digit (dorsal branch from ulnar n)

Question 23

Sensory loss - T1:

Answer 23

Medial side of cubital fossa (pronator teres)

Question 24

Motor loss - C5:

Answer 24

Arm abduction - supraspinatus and deltoid

Question 25

Motor loss - C6:

Answer 25

Forearm flexors - brachialis and biceps brachii

Question 26

Motor loss - C7:

Answer 26

Forearm extensors - triceps

Question 27

Motor loss - C8:

Answer 27

Digital flexors - flexor digitorum profundus

Question 28

Motor loss - T1:

Answer 28

Index, middle, and ring finger abduction and adduction - dorsal and palmar interosseii

Question 29

Winged scapula caused by

Answer 29

Loss of long thoracic nerve (serratus anterior) can’t laterally rotate scapula thus can’t fully abbduct

Question 30

Ulnar nerve damage at wrist

Answer 30

Clawing more apparent since FDP is spared and is not opposed by the lumbrical actions…CAN MAKE A FIST SINCE FDP SPARED!!