Brachial Plexus

Question 1

2 branches of the UPPER TRUNK

Answer 1

1) suprascapular nerve

2) branch to subclavius

Question 2

What is the common variant for teres major innervation?

Answer 2

up to 20% THORACODORSAL nerve

normal = lower subscapular nerve

Question 3

LONG THORACIC nerve innervates ____

Answer 3

serratus anterior

Question 4

3 muscles innervated by the MUSCULOCUTANEOUS nerve

Answer 4

coracobrachialis
biceps brachii
brachioradialis

Question 5

4 muscles innervated by the MEDIAN nerve (before AIN branches)

Answer 5

pronator teres
FCR
FDS
palmaris longus

Question 6

3 muscles innervated by the ANTERIOR INTEROSSEOUS nerve

Answer 6

FPL
lateral FDP
pronator quadratus

Question 7

3 muscles innervated by the RECURRENT MOTOR BRANCH of the median nerve

Answer 7

opponens pollicis
abductor pollicis brevis
flexor pollicis brevis (superficial head)

Question 8

MEDIAN nerve is derived from the ____ cord(s)

Answer 8

MEDIAL & LATERAL

Question 9

MEDIAN nerve initially travels ____ to the ____ artery

Answer 9

LATERAL / BRACHIAL

Question 10

MEDIAN nerve (in the forearm) travels between ____ and ____ muscles

Answer 10

FDP / FDS

Question 11

AXILLARY nerve is derived from _____ spinal roots and is a direct continuation of the _____ cord

Answer 11

C5 & C6 spinal roots / POSTERIOR cord

Question 12

AXILLARY nerve (in the axilla) lies posterior to the _____ and anterior to _____

Answer 12

posterior to AXILLARY ARTERY / anterior to SUBSCAPULARIS

Question 13

After exiting the quadrangular space, the axillary nerve passes medial to the _____ then divides into 3 terminal branches

Answer 13

medial to the SURGICAL NECK of the humerus

Question 14

MUSCULOCUTANEOUS nerve is the terminal branch of the ____ cord

Answer 14

LATERAL cord

Question 15

MUSCULOCUTANEOUS nerve leaves the axilla and pierces ____ then passes down the arm superficial to ____ and deep to ____

Answer 15

pierces CORACOBRACHIALIS / superficial to BRACHIALIS / deep to BICEPS brachii

Question 16

MUSCULOCUTANEOUS nerve pierces deep fascia lateral to biceps brachii, then emerges LATERAL to ____ and ____

Answer 16

emerges lateral to BICEPS TENDON & BRACHIORADIALIS

Question 17

ULNAR nerve is derived from ____ spinal roots and is a continuation of the ____ cord.

Answer 17

C8 & T1 spinal roots / MEDIAL cord

Question 18

Which nerve supplies the articular branch of the shoulder?

Answer 18

AXILLARY nerve

Question 19

Which nerve supplies the articular branch of the elbow?

Answer 19

ULNAR nerve

Question 20

ULNAR nerve (in the forearm) pierces ____ and travels deep to ____

Answer 20

pierces FCU and travels deep to FCU

Question 21

3 HYPOTHENAR muscles

Answer 21

FDMB (flexor digiti minimi brevis)
AbDM (abductor digiti minimi)
ODM (opponens digiti minimi)

Question 22

RADIAL nerve exits the axilla via the ____ and give branches to the ____

Answer 22

exits via the TRIANGULAR interval / branches to LONG & LATERAL TRICEPS brachii

Question 23

RADIAL nerve travels anterior to the ____ through the cubital fossa between ____ and ____

Answer 23

anterior to the LATERAL EPICONDYLE / between BRACHIALIS & BRACHIORADIALIS

Question 24

POSTERIOR INTEROSSEOUS nerve emerges through the ____ at the

Answer 24

through the SUPINATOR muscle at the ARCADE OF FROHSE

Question 25

POSTERIOR INTEROSSEOUS nerve innervates 8 muscles

Answer 25

EDC / EDM / ECU (common extensors) | Supinator / AbdPL / EPB / EPL / EIP (deep extensors)

Question 26

Last muscle to recover from a PIN palsy

Answer 26

EIP (extensor indicis proprius)

Question 27

3 muscles of the MOBILE WAD

Answer 27

brachioradialis ECRL ECRB

Question 28

Which nerve roots are involved with: ERB PALSY?

Answer 28

C5 & C6

Question 29

Which nerve roots are involved with: KLUMPKE PALSY

Answer 29

C8 & T1

Question 30

Which brachial plexus palsy is most common?

Answer 30

ERB Palsy (C5 & C6)

Question 31

How does ERB PALSY present?

Answer 31

ADDucted & INTERNALLY rotated at shoulder + PROnated & EXTENDed at the elbow -- affects axillary (C5), suprascapular (C5), musculocutaneous (C5), and radial nerves (C6)

Question 32

How does KLUMPKE palsy present?

Answer 32

CLAW HAND -- wrist in extreme extension 2/2 unopposed extensors + hyperextension of MCP & IP flexion 2/2 loss of hand intrinsics

Question 33

Why do upper plexus injuries have an improved prognosis?

Answer 33

Because hand function is preserved

Question 34

If a patient presents with Horner's Syndrome after traumatic UE injury, which muscles should be evaluated and why?

Answer 34

Evaluate SERRATUS anterior (long thoracic n.) and RHOMBOIDS (dorsal scapular n.) -- if they are functioning then it is more likely that C5 injury is postganglionic

Question 35

If sensory nerve action potentials (SNAPs) are normal on nerve conduction velocity testing, but the patient is still insensate in a nerve distribution, then the injury is __PRE or POST__ -ganglionic

Answer 35

PRE-ganglionic nerve injury