THE AXILLA AND BRACHIAL PLEXUS

Question 1

what are the lymph nodes of the upper limbs?

Answer 1

apical lateral central, posterior and pectoral

Question 2

what are the roots of the brachial plexus?

Answer 2

anterior rami of C5-T1

Question 3

there are 7 cevrical vertebrae so why in the brachial plexus do we have C8?

Answer 3

because we name cervical nerves by the vertebrae that lies beneath them so C8 would lie above T1

Question 4

how do we name thoracic nerves?

Answer 4

using the vertebrae above the nerve root

Question 5

what are the 5 segments of the brachial plexus?

Answer 5

roots
trunks
divisions
cords
branches

Question 6

what are the trunks of the brachial plexus?

Answer 6

superior middle and infeiror

Question 7

what are the divisions of the brachial plexus?

Answer 7

the 3 anterior divisions, one from each trunk

the 3 posterior divisions, one from each trunk

Question 8

what are the cords of the brachial plexus?

Answer 8

lateral, posterior and medial

Question 9

what are the branches of the brachial plexus?

Answer 9

musculocutaneous
axillary
radial
median 
ulnar

Question 10

what branches does the lateral cord give rise to?

Answer 10

the musculocutaneous nerve and, along with the medial cord, the median nerve

Question 11

which branches does the posterior cord give rise to?

Answer 11

axillary and radial nerves

Question 12

what branches does the medial cord give rise to?

Answer 12

ulnar nerve and, along with the lateral cord, the median nerve

Question 13

how do we exclusively test nerve function for the media nerve?

Answer 13

tip of the index or middle finger

Question 14

how do we test for the ulnar nerve exclusively?

Answer 14

tip of the little finger

Question 15

how do we test for the radial nerve exclusively?

Answer 15

in the webbing between thumb and index finger

Question 16

what are the signs of radial nerve injury?

Answer 16

loss of sesnation over dorsal web between thumb/index finger

weakness of extensors = wrist drop

Question 17

what would damage to T1 do?

Answer 17

causes paralysis of the forearm flexor and the intrinsic muscles of the hand

Question 18

what is Erb’s palsy?

Answer 18

an upper brahcial plexus injury -injury to C5 and C6

This causes muscles around the shoulder to be paralysed so the arms hang limply by the side with loss of sensation.

Question 19

what is Klumpke’s paralysis (aka horner syndrome)?

Answer 19

injury to T1 - loss of sesnaton of medial side of forearm and loss of motor function in small muscles of the hand
may result due to a difficult delivery

Question 20

describe the course of the radial nerve through the arm?

Answer 20

exits axilla inferiorly , descends fown the arm within the radial grrove wrapping around the humerus laterally. It travels anteror to the lateral epicondyle of the hymerys and through the cubital fossa to enter the forearm

Question 21

describe the course of the musculocutaneous nerve?

Answer 21

it leaves the exilla nd puerces the coracobrachialis muscle and then passes down the arm, superficialt to brachialis but deep to biceps brachii. it pierces the deep fascia lateral to biceps brachii to emerge lateral to biceps tendon. it continues into the forearm as the lateral cutaneous nerve

Question 22

outline the course of the medial nerve?

Answer 22

it descends down the arm lateral to the brachial artery. halfway down the arm it corsses over the brachial artery and is situated medially. it enters the anterior compartment of the forearm via the cubital fossa. in the forarm it travels between the flexor digitorum profundus and flexor digitorum superficialis muscles

Question 23

describe the course of the ulnar nerve?

Answer 23

it descends down the medial aspect of the arm with the brachial artery located lateral. at the midpoint of the arm, the ulnar nerve penetrates the medial fascial septum to enter the posterior compartment of the arm. in the forearm the ulnar nerve pierces the 2 heads of the flexor capri ulnaris and travels deep to the muscle alongisde the ulna.

Question 24

what nerve does root C5 give off?

Answer 24

the dorsal scapular nerve

Question 25

what nerve do roots C5,6,7 give off?

Answer 25

the long thoracic nerve

Question 26

what nerve do roots C5 and 6 give off?

Answer 26

the nerve to subclavius

Question 27

what nerve do the lateral and medial cords give off?

Answer 27

the lateral and medial pectoral nerves which come together

Question 28

what nerves does the posterior cord give off?

Answer 28

``` radial nerve axillary nerve lower subscapular nerve thoracodorsal nerve upper subscapular nerve ```

Question 29

what is the function of the dorsal scapular nerve?

Answer 29

motor: rhomboid muscle and levator scapulae muscles

Question 30

what is the function of the suprascapular nerve?

Answer 30

motor: supraspinatus and infraspinatus muscles

Question 31

what is the function of the nerve to subclavian?

Answer 31

motor: innvrtaion to subclavius muscle

Question 32

what is the functuon of the lateral and medial pectoral nerve?

Answer 32

motor: pectoralis major and minor muscles respectively

Question 33

what is the function of the medial cutaneous nerve of the forearm and arm?

Answer 33

sensory: medial skin of forearm and arm respectively

Question 34

what is the function of the lower subscapularis nerve?

Answer 34

motor: subscapularis and teres major

Question 35

what is the function of the thoracodorsal nerve?

Answer 35

motor: latissimus dorsi muscle

Question 36

what is the function of the upper subscapular nerve?

Answer 36

motor: subscapularis

Question 37

what does the musculocutaneous nerve innervate?

Answer 37

motor: muscles of anterior arm sensory: lateral side of forarm

Question 38

what does the axillary nerve innervate?

Answer 38

motor: teres minor and deltoid sensory: glenohumeral joint and skin covering inferuor portion of deltoid (sergeants patch)

Question 39

what does the radial nerve innervate?

Answer 39

motor: all muscles of posterior arm and forearm sensory: skin of posterior arm + forearm, lateral edge of thumb on palmar side, lateral hand and proximal 3.5 fingers on dorsal hand

Question 40

what is the function of the median nerve?

Answer 40

motor: muscles of anterior forearm except flexor capri ulnaris and the ulnar half of flexor digitorum profundus. thenar muscles and lateral lumbricals in hand sensory: lateral 3.5 digits on adjacent palm on palmar side and distal asoects of lateral 3.5 digits on dorsal side

Question 41

what is the function of the ulnar nerve?

Answer 41

motor: flexor carpi ulnaris and ulnar half of flexor digitorum profundus, most intrinsic muscles of the hanf sensory: medial 1.5 digits and adjacent palm