5/1/2015 "Gross Anatomy Brachial Plexus Dana M. Mihaila"

Question 1

The brachial plexus is responsible for the motor innervation of all muscles in the upper extremity except:

Answer 1

1. trapezius (CN XI accessory)

2. levator scapulae (C3-C4)

Question 2

Supraspinatus paresis results in weakness of:

Answer 2

arm abduction

Question 3

Infraspinatus paresis results in impaired:

Answer 3

External arm rotations

Question 4

Upper and lower subscapular nerves are branches of:

Answer 4

Posterior cord
They both have C5 and C6 fibers
MOTOR only

Question 5

How is thoracodorsal nerve different from its neighbors, upper and lower subscapular nerve?

Answer 5

1. Different innervations:
   Upper Subscap –> Subscapularis muscle
   Lower Subscap –> Subscapularis muscle AND teres major
   Thoracodorsal –> lattisimus dorsi
2. Thoracodorsal nerve has C8, C6 and C7 fibers, whereas the other 2 have only C5 and C6 fibers

These are all MOTOR only

Question 6

T/F: Axillary nerve has sensory and motor fibers

Answer 6

Fucking true
Motor to deltoid and ters minor
Sensory to capsule of shoulder joint and skin on upper lateral arm

Question 7

What is the largest branch of the brachial plexus?

Answer 7

Radial nerve

Question 8

Lateral cutaneous nerve of the arm is a branch of?

Answer 8

Axillary nerve

Question 9

Posterior cutaneous nerve of the arm is a branch of?

Answer 9

Radial nerve

Sensory

Question 10

Posterior cutaneous nerve of the forearm is a branch of?

Answer 10

Radial nerve

Sensory

Question 11

Triceps and Anconeus have motor innervation by what nerve?

Answer 11

Radial nerve

Question 12

What muscles of the forearm does radial nerve supply motor innervation to?

Answer 12

Brachioradialis
Extensor carpi radialis longus
Extensor carpi radialis brevis

Question 13

After radial nerve exits the supinator muscle, it is called?

Answer 13

Posterior interosseus nerve

MOTOR only

Question 14

Extensor digitorum, Extensor digiti minimi, Extensor carpi ulnaris, Abductor pollicis longus, Extensor pollicis longus, extensory pollicis brevis and extensor indicis, all supplied by what nerve?

Answer 14

Posterior interosseus nerve
Motor
Terminal branch of radial nerve

Question 15

Sensory innervation to skin on back of hand, back of first 4 digits is supplied by:

Answer 15

Radial nerve superficial branch

Question 16

The deep branch of radial nerve innervates what muscle?

Answer 16

Supinator

Motor

Question 17

Wrist drop, axillary injury, are associated with lesion of what cord of the brachial plexus?

Answer 17

Posterior cord (radial nerve)
Saturday night palsy

Question 18

What fibers does musculocutaneous nerve have?

Answer 18

Sensory and Motor
Sensory - becomes lateral cutaneous antebrachial nerve
Motor to coracobirachialis, biceps and brachialis

Question 19

Biceps weakness, atrophy of biceps/brachialis muscles, weakened biceps reflex reflect a lesion of what nerve?

Answer 19

Musculocutaneous (C5-C7)

Lateral cord

Question 20

Flexor carpi ulnaris and flexor digitorum profundus 3 and 4 are innervated by:

Answer 20

Ulnar nerve
Medial cord
Motor

Question 21

The skin over the hypothenar eminence is supplied by what nerve?

Answer 21

Ulnar nerve palmar cutaneous branch

Sensory

Question 22

Claw hand is a lesion around the elbow of what nerve?

Answer 22

Ulnar nerve

Question 23

T/F: The median nerve gives no muscular branches before the elbow.

Answer 23

True

Question 24

Median nerve innervates 4 muscles of the forearm. Name them:

Answer 24

Pronator teres
Flexor carpi radialis
Palmaris longus
Flexor digitorum superficialis
**All motor**

Question 25

Anterior interosseus nerve is a branch of:

Answer 25

Median nerve

Question 26

Name the nerve that motor innervates these muscles:
Flexor pollicis longus
Flexor digitorum profundis I and II
Pronator quadratus

Answer 26

Anterior interosseus nerve – branch of median nerve

Question 27

Skin of the thenar eminence is innervated by:

Answer 27

Median nerve

Sensory

Question 28

The hand of benediction is a sign of what nerve lesion?

Answer 28

Median nerve (motor fibers)

Question 29

Carpal Tunnel Syndrome is a lesion of:

Answer 29

Median nerve

Question 30

Damage to the 5th and 6th cervical roots of the brachial plexus results in what pathology?

Answer 30

Erb-Duchenne type upper plexus paralysis
Superior trunk palsy
Baby with arm palsy after diffcult birth
Waiter’s tip sign

Question 31

Klumpke (lower plexus paralysis) can result in what syndrome?

Answer 31

Horner syndrome

Question 32

Brachial plexus anterior division innervates:

Answer 32

Anterior muscles;

Posterior division innervates posterior muscles.

Question 33

Winging scapula indicates damage to what nerve?

Answer 33

Long thoracic nerve

Question 34

What travels through the quadrangular space?

Answer 34

Posterior humeral circumflex artery

Axillary nerve

Question 35

In what scenario would you put too much pressure on the quadrangular space?

Answer 35

Crutches

Axillary nerve compression

Question 36

A lesion of the radial nerve in what space would cause all fx of the nerve to be lost, as in windmill pitcher’s radial neruopathy?

Answer 36

Triangular interval

Question 37

Musculocutaneous nerve can be seen piercing what muscle?

Answer 37

Choracobrachialis

Question 38

What is carpet carrier syndrome?

Answer 38

Lesion of musculocutaneous nerve

Compression of corachobrachialis muscle

Question 39

Venipuncture can damage what nerve?

Answer 39

Musculocutaneous, at elbow level

Question 40

What is the million dollar nerve and how does it get its name?

Answer 40

Recurrent branch of median nerve

Inability to move thumb after carpal tunnel release surgery