Brachial Plexus

Question 1

What are the five segments of the brachial plexus?

Answer 1

Roots, Trunks, Divisions, Cords, Nerves

Question 2

What nerves compose the upper, middle, and lower trunks?

Answer 2

C5-6

C7

C8,T1

Question 3

The lateral cord stems from what spinal nerves? What divisions?

Answer 3

C5-7

Anterior division of the upper and middle trunk

Question 4

The medial cord contains nerves from what spinal roots? What divisions does it contain?

Answer 4

C8 and T1

Anterior division of lower trunk

Question 5

The posterior cord is comprised of what spinal nerve fibers? What division does it originate from?

Answer 5

C5-C8

All three posterior divisions

Question 6

What cord and spinal nerves does the musculocutaneous nerve arise from?

Answer 6

Lateral cord; C5-7

Question 7

What cord and spinal nerves does the median nerve come from?

Answer 7

Merged lateral and medial cord

Spinal nerves C6-T1

Question 8

What cord and spinal nerves results in the axillary n.?

Answer 8

Posterior cord

C5-6

Question 9

What cord and spinal nerves results in the radial n.?

Answer 9

Posterior cord

C5-8

Question 10

What cord and spinal nerves results in the ulnar nerve?

Answer 10

Medial cord

C8-T1

Question 11

What spinal nerve gives rise to the dorsal scapular n.?

Answer 11

C5 (near trunk)

Question 12

What spinal nerve gives rise to the suprascapular n.?

Answer 12

C5-6 (@ trunk)

Question 13

What spinal nerve gives rise to the subclavian?

Answer 13

C5-6

Question 14

What spinal nerve gives rise to the long thoracic?

Answer 14

C5-7

Question 15

What spinal nerve gives rise to the lateral pectoral?

Answer 15

C5-6 of lateral cord

Question 16

What spinal nerve gives rise to the upper subscapular?

Answer 16

C5 of posterior cord

Question 17

What spinal nerve gives rise to the thoracodorsal n.?

Answer 17

C6-8 of posterior cord

Question 18

What spinal nerve gives rise to the lower subscapular?

Answer 18

C6 of posterior cord

Question 19

What spinal nerve gives rise to the medial pectoral n?

Answer 19

C8-T1 of medial cord

Question 20

What spinal nerve gives rise to the medial cutaneous nerves of arm and forearm?

Answer 20

C8-T1 medial cord

Question 21

What spinal nerve is generally responsible for abduction of the shoulder?

Answer 21

C5

Question 22

What spinal nerve is generally responsible for extension of the wrist?

Answer 22

C6

Question 23

What spinal nerve is generally responsible for fingers?

Answer 23

C7

Question 24

What spinal nerve is generally responsible for wrist flexion?

Answer 24

C7

Question 25

What spinal nerve is generally responsible for finger flexion?

Answer 25

C8

Question 26

What spinal nerve is generally responsible for ab/adduction of fingers?

Answer 26

T1

Question 27

What spinal nerve is tested with the biceps reflex? Brachioradialis reflex? Triceps reflex?

Answer 27

C5; C6; C7

Question 28

What nerve’s dermatome lies on the shoulder?

Answer 28

C5

Question 29

What nerve’s dermatome lies on the lateral lower arm, forearm, and hand?

Answer 29

C6

Question 30

What nerve’s dermatome lies on the middle portion of the palm and middle finger, plus half of the two fingers surrounding middle; and in the middle of the posterior forearm to the elbow?

Answer 30

C7

Question 31

What nerve’s dermatome lies on the medial hand and half of ring finger, plus the posteriomedial forearm?

Answer 31

C8

Question 32

What nerve’s dermatome lies on the lateral forearm and posterio-lateral arm?

Answer 32

T1

Question 33

What are the axillary nerve’s muscle branches? Sensory?

Answer 33

Teres minor and deltoid Superior lateral cutaneous n.

Question 34

What are the muscular and sensory branches of the musculocutaneous nerve?

Answer 34

Coracobrachialis, biceps brachii, brachialis Lateral cutaneous nerve of the forearm

Question 35

What are the muscular and sensory branches of the median n.?

Answer 35

Anterior compartment of forearm (EXCEPT flexor carpi ulnaris and 1/2 of the flexor digitorum profundus); thenar muscles of hand, first two lumbricals 1st 7 palmar digital nn (first 3 and 1/2 digits on palm)

Question 36

What are the muscular and sensory branches of the ulnar nerve?

Answer 36

Flexor carpi ulnaris and 1/2 of the flexor digitorum profundus; intrinsic muscles of the hand (except thenar and 1st 2 lumbercals) Common and proper palmar and dorsal digitals

Question 37

What are the muscular and sensory branches of the radial nerve?

Answer 37

Posterior compartment muscles of arm and forearm; NONE IN HAND Inferior lateral brachial cutaneous n., posterior cutaneous n of forearm; dorsal digitals for first 2.5 digits

Question 38

What are the supraclavicular nerves? What do they innervate?

Answer 38

Dorsal scap- levator scapulae and romboids suprascapular- supraspinatus and infraspinatus subclavian- subclavius long thoracic- serratus anterior

Question 39

What are the posterior cord nerves and what do they innervate?

Answer 39

Upper subscapular- subscapularis Lower subscapular- subscapularis and teres major Thoracodorsal- latissimus dorsi

Question 40

What are the median chord nerves and what do they supply?

Answer 40

Medial pectoral n.- pec minor and major Medial cutaneous nerve of arm/forearm- the name says it all (think C8-T1 dermatome)

Question 41

What are the nerves of the lateral cord and what muscle do they supply?

Answer 41

Lateral pectoral n- pec major

Question 42

Severance of the axillary nerve would cause what issue?

Answer 42

Numbness along lateral and posterior shoulder; no abduction of shoulder joint

Question 43

Severing the musculocutaneous nerve could cause what complication?

Answer 43

Numbness along the lateral aspect of the forearm; inability to flex at the elbow or internally rotate the glenoid fossa

Question 44

Severing the median nerve can cause what complications?

Answer 44

Proximal severance: lack of flexion power in the forearm, inability to move thumb and digits 1 and 2 very well

Question 45

Severance of the ulnar nerve results in what complications?

Answer 45

Limits flexion of wrist; limits mobility of fingers 4-5; numbness and tingling on fingers 4-5

Question 46

Severance of the radial nerve can cause what complications?

Answer 46

Limits extension at elbow and forearm; numbness along posterior and lateral arm