The brachial plexus

Question 1

plexus

Answer 1

major nerve network

Question 2

spinal cord carries

Answer 2

sensory and motor info

Question 3

posterior route supplies …

Answer 3

sensory info

Question 4

anterior route supplies …

Answer 4

motor info

Question 5

ramus

Answer 5

division

Question 6

spinal nerve splits into

Answer 6

posterior ramus and anterior ramus

Question 7

anterior rami is composed of which spinal nerves

Answer 7

• C5
• C6
• C7
• C8
• T1

Question 8

roots

Answer 8

anterior rami of
- C5
- C6
- C7
- C8
- T1

Question 9

Trunks

Answer 9

• C5 + C6 = Superior trunk
• C7 = middle trunk
• C8 + T1 = Inferior trunk

Question 10

Divisions

Answer 10

Each trunk divides into an anterior and posterior division
- All posterior divisions merge in the middle
- Superior anterior + middle anterior merge
- Inferior anterior continues on its own

Question 11

Cords

Answer 11

named in relation to axillary artery
- superior anterior + middle anterior = lateral
- All posterior divisions = posterior
- Inferior superior = medial

Question 12

Terminal branches

Answer 12

All on their own except median
Each cord splits in 2
- Lateral = Musculocutaneous + median
- Posterior = axillary + radial
- medial = ulnar + median
- Lateral + medial = median

Question 13

How to tell nerves and arteries apart?

Answer 13

• Both similar white/cream/yellow colour
• When nerves are pinched they bounce back
• arteries don’t bounce back

Question 14

Musculocutaneous nerve

Answer 14

derived from lateral cord

Question 15

median nerve

Answer 15

derived from lateral and medial cords

Question 16

axillary nerve

Answer 16

derived from posterior cord

Question 17

radial nerve

Answer 17

derived from posterior cord

Question 18

ulnar nerve

Answer 18

derived from medial cord

Question 19

Roots pass through posterior triangle of the neck
What borders form this gap?

Answer 19

• middle scalene
• anterior scalene
• first rib

Question 20

dorsal scapular nerve
what is it derived from?
what does is innervate?
where is it?

Answer 20

deviates off C5
passes posteriorly piercing middle scalene to travel along medial border of scapula
rhomboids and levator scapulae

Question 21

long thoracic
what is it derived from?
what does is innervate?
where is it?

Answer 21

comes from C5, C6, and C7
innervates serratus anterior
passes vertically down neck and medial axillary wall

Question 22

suprascapular nerve
what is it derived from?
what does is innervate?
where is it?

Answer 22

• derived from superior trunk of C5 and C6
• supraspinatus and infraspinatus
• passes laterally though posterior triangle of neck, deep to trapezius to enter supraspinous fossa through suprascapular notch

Question 23

nerve to subclavius
what is it derived from?
what does is innervate?
where is it?

Answer 23

• derived from superior trunk
• subclavius
• passes anteroinferiorly over subclavian artery and vein

Question 24

lateral pectoral nerve
what is it derived from?
what does is innervate?
where is it?

Answer 24

• derived from lateral cord
• pec major
• passes anteriorly together with thoracoacromial artery to penetrate clavipectoral fascia

Question 25

inferior subscapular
what is it derived from?
what does is innervate?

Answer 25

derived from posterior cord
- subscapularis and teres major

Question 26

thoracodorsal nerve
what is it derived from?
what does is innervate?
where is it?

Answer 26

derived from posterior cord
- latissimus dorsi
- passes vertically along posterior axillary wall

Question 27

superior subscapular nerve
what is it derived from?
what does is innervate?

Answer 27

• derived from posterior cord
• subscapularis and teres major

Question 28

medial cutaneous nerve of forearm
what is it derived from?
what does is innervate?

Answer 28

• derived from medial cord
• skin over biceps and over medial forearm down to wrist

Question 29

medial cutaneous nerve of arm
what is it derived from?
what does is innervate?

Answer 29

• derived from medial cord
• supplies skin on medial side of distal 1/3 of arm

Question 30

medial pectoral nerve
what is it derived from?
what does is innervate?

Answer 30

• derived from medial cord
• pec major and minor

Question 31

damage to long thoracic nerve causes?

Answer 31

winged scapula
burning pain in posterior shoulder or scapula

Question 32

suprascapular nerve injury

Answer 32

• shoulder pain/weakness of supraspinatus and infraspinatus
• difficulty abducting arm
• difficulty in lateral rotation

Question 33

musculocutaneous nerve
what is it derived from?
what does is innervate?
where is it?

Answer 33

• terminal branch from lateral cord
• All 3 flexor arm muscles
• passes laterally to penetrate coracobrachialis and pass between biceps brachii and brachialis

Question 34

ulnar nerve
what is it derived from?
what does is innervate?
where is it?

Answer 34

• large terminal branch of medial cord
• some intrinsic muscles of hand
• passes through arm and forearm into hand

Question 35

axillary sheath

Answer 35

• extension of deep cervical fascia
• encloses the first portion of axillary artery/nerve and brachial plexus

Question 36

types of brachial plexus injuries

Answer 36

• avulsion
• rupture
• neuroma
• neuropraxia

Question 37

avulsion

Answer 37

nerve is torn from its attachment to the spinal cord
surgical repair is impossible

Question 38

rupture

Answer 38

• nerve is torn but not at spinal cord
  surgical repair possible

Question 39

neuroma

Answer 39

• scar tissue forms, putting pressure on nerve
  can heal without surgery

Question 40

neuropraxia

Answer 40

nerve is stretched but not torn
usually heals without surgery

Question 41

upper plexus palsies

Answer 41

Erb-Duchenne palsy (waiters tip)
tearing of roots C5 and C6

Question 42

lower plexus injuries

Answer 42

Klumpke paralysis
tearing of T1 root