Brachial plexus

Question 1

What is the order of the brachial plexus from vertebrae to the axilla?

Answer 1

Roots >> Trunks (3) >> Divisions >> (6) >> Cords (3)

Question 2

What nerves makeup the brachial plexus?

Answer 2

C5, C6, C7, C8, T1

http://teachmeanatomy.info/upper-limb/nerves/brachial-plexus/#Roots

Question 3

What nerves make up the upper, middle and lower trunks?

Answer 3

C5+C6 = upper C7 = middle C8+T1 = lower

http://teachmeanatomy.info/upper-limb/nerves/brachial-plexus/#Roots

Question 4

What divisions make up the cords?

Answer 4

Anterior div of Upper trunk (C5+C6) + Anterior div of Middle trunk (C7) makes up the Lateral Cord

Posterior division of Upper trunk, Middle trunk, and lower trunk (C8+T1) makes up the Posterior Cord

Anterior div of Lower trunk makes up the Medial cord

http://teachmeanatomy.info/upper-limb/nerves/brachial-plexus/#Trunks

Question 5

What nerve comes off the C5 root?

Which muscles are innervated by this nerve?

Answer 5

Dorsal scapular n.

Rhomboids and Levator Scapulae

Question 6

The ___ nerve is a combination of branches from C5, C6 and C7 roots

What muscle does it innervate?

Answer 6

Long thoracic nerve

Serratus anterior

Question 7

Name one of the 2 nerve(s) that come off the Upper Trunk

It innervates the ___ and ___ muscles of the scapula.

Answer 7

Suprascapular n.

Supraspinatus and Infraspinatus

Question 8

The nerve to ___ comes off the Upper trunk

Answer 8

Subclavius m.

Question 9

Which nerve(s) branches off the Lateral cord? (hint: L pect + M)

Answer 9

Lateral pectoral n. and Musculocutaneous n.

Question 10

Name the nerves that branch off the Posterior Cord (hint: ULTRA w/ 2 subscapulars)

Answer 10

Upper subscapular n

Lower subscapular n

Thoracodorsal n (between Upper and Lower subscapular ns.)

Radial n

Axillary n

Question 11

What nerve is the terminal branch of the posterior cord?

Answer 11

Radial nerve

Question 12

What is the first nerve that comes off of the MediaL cord?

Answer 12

MediaL pectoral n

Question 13

The ___ ___ n of the arm and ___ ___ n of the forearm come off the medial cord

Answer 13

Medial cutaneous nerve of the arm

Medial cutaneous nerve of the forearm

Question 14

State the nerve that is the terminal branch of the medial cord

Answer 14

Ulnar n

Question 15

Altogether, what are the nerves that come off the Medial cord? (hint: Ulnar takes 2 many Meds for her cut arms and pect)

Answer 15

Ulnar n

Medial cutaneous n of the forearm

Medial cutaneous n of the arm

Medial pectoral nerve

Question 16

Which nerve gets contributions from the lateral and medial cords? (the happy median)

Answer 16

The median n.

Question 17

The anterior division of upper trunk primarily contributes to the ___ nerve

Answer 17

Musculocutaneous n.

Question 18

Anterior division of C7 and some C8 primarily contributes to the ___ n

Answer 18

Median nerve

Question 19

The anterior division of T1 primarily contributes to what nerve?

Answer 19

Ulnar nerve

Question 20

Injury to the upper brachial plexus results in ___ palsy, which results when the head is pulled away from the body and is characterized by impaired function of proximal upper limb muscles. The phenotype of this condition is ___ hand, due to loss of ___ and ___.

Answer 20

Erb’s palsy

Waiter’s tip hand

ABduction and Supination

http://teachmeanatomy.info/upper-limb/nerves/brachial-plexus/#Clinical_Relevance_Injury_to_the_Brachial_Plexus

Question 21

Injury to what brachial plexus trunk results in Klumpke’s palsy? How would this injury occur and what is its phenotype? What action of what muscles is impaired?

Answer 21

Lower brachial plexus trunk

Injury results from arm being pulled away from body

Phenotype is clawed hand

Flexion of the intrinsic muscles of the hand (lumbricals) at metacarpophalangeal joints

http://teachmeanatomy.info/upper-limb/nerves/brachial-plexus/#Clinical_Relevance_Injury_to_the_Brachial_Plexus

Question 22

The cords of the brachial plexus are named in relation to what structure?

Answer 22

Axillary art