nerves

Question 1

function of brachial plexus

Answer 1

rearrange nerve fibres from C5-T1 into bundles travelling to appropriate parts of the limb

Question 2

what bundle in the brachial plexus do all nerves supplying extensor muscles pass through

Answer 2

posterior cord

Question 3

what bundles in the brachial plexus do all nerves supplying flexor muscles pass through

Answer 3

lateral and medial cords

Question 4

2 main nerves of posterior cord

Answer 4

axillary nerve, radial nerve

Question 5

general structure of brachial plexus

Answer 5

roots (formed by anterior rami of C5-T1) -> trunks -> divisions -> cords -> terminal branches (peripheral nerves)

Question 6

what is the nerve branch coming off just at C5 root, and what muscle does it supply

Answer 6

dorsal scapular nerve, supplying rhomboids (occasionally levator scapulae)

Question 7

what is the terminal branch coming off just C5-C7 roots, and what muscle does it supply

Answer 7

long thoracic nerve, supplying serratus anterior

Question 8

what is the nerve branch coming off just C5 and C6 roots, and what muscles does it supply

Answer 8

suprascapular nerve, supplying supraspinatus and infraspinatus (gleno-humeral joint)

Question 9

what is the nerve branch coming off the junction of C5 and C6 roots (Erb’s point), and what muscles does it supply

Answer 9

subclavian nerve, supplying subclavias and sternoclavicular joint (accessory phrenic root innervates diaphragm)

Question 10

what are the 3 trunks, and what nerve fibres do they consist of

Answer 10

superior (C5,6), middle (C7), inferior (C8,T1)

Question 11

2 divisions of each trunk

Answer 11

anterior, posterior

Question 12

what divisions does the lateral cord consist of

Answer 12

anterior division of superior trunk (C5,6), anterior division of middle trunk (C7)

Question 13

what divisions does the posterior cord consist of

Answer 13

posterior divisions of superior trunk (C5,6), middle trunk (C7), and inferior trunk (C8,T1)

Question 14

what division does the medial cord consits of

Answer 14

anterior division of inferior trunk (C8,T1)

Question 15

what is the nerve branch coming off the lateral cord, and what muscles does it supply

Answer 15

lateral pectoral nerve, supplying pectoralis major, but with some lateral fibres passing to pectoralis minor via branch of medial pectoral nerve)

Question 16

what is the terminal branch coming off the lateral cord, and what muscle compartment does it supply

Answer 16

musculocutaneous nerve, supplying muscles of anterior compartment of arm (biceps brachii, brachialis, caraco-brachialis), and skin of lateral aspect of forearm

Question 17

what are the 3 nerve branches coming off the posterior cord, and what muscles does they supply

Answer 17

upper subscapular nerve (supplying superior portion of subscapularis), thoracodorsal nerve (supplying latissimus dorsi), lower subscapular nerve (supplying inferior portion of subscapularis and teres major)

Question 18

what are the 2 terminal branches coming off the posterior cord, and what muscle compartments do they supply

Answer 18

axillary nerve (supplying gleno-humeral shoulder joint, teres minor, deltooid muscles, skin of superolateral arm), radial nerve (supplying all muscles of posterior compartments of arm and forearm, the skin of posterior and inferolateral arm, posterior forearm and dorsum of hand lateral to axial line of ring finger)

Question 19

what are the 3 nerve branches coming off the medial cord

Answer 19

medial pectoral nerve (supplying pectoralis minor and sternocostal part of pectoralis major), medial cutaneous nerve of arm, medial cutaneous nerve of forearm

Question 20

what is the terminal branch of the medial cord, and what muscles does it supply

Answer 20

ulnar nerve, supplying flexor carpi ulnaris and ulnar half of flexor digitorum profundus (forearm), most intrinsic hand muscles, and skin of hand medial to axial line of ring finger

Question 21

what is the terminal branch of the lateral root of the lateral cord and medial root of medial cord, and what muscle compartments does it supply

Answer 21

median nerve, supplying muscles of anterior forearm (excluding flexor carpi ulnaris and ulnar half of flexor digitorum profundus), 5 intrinsic muscles in thenar half of palm, and palmar skin

Question 22

what artery are the cords of the brachial plexus named in relation to

Answer 22

axillary artery (so posterior behind, lateral is lateral and medial is medial)

Question 23

4 supraclavicular branches of brachial plexus

Answer 23

dorsal scapular, long thoracic, suprascapular, subclavian nerve

Question 24

5 infraclavicular branches of brachial plexus (excluding terminal branches of cords or cutaneous nerves)

Answer 24

lateral pectoral, medial pectoral, upper subscapular, lower subscapular, thoracodorsal

Question 25

5 terminal branches of brachial plexus

Answer 25

axillary, radial, median, ulnar, musculocutaneous