CNS Exam 3

What levels make up the brachial plexus?

C5-T1

What is the progression of the brachial plexus?

roots→trunks→divisions→cords→ terminal nerves

How many cervical ganlions are there? Where do they travel?

3→ travel through anterior and middle scalene

Tight scalenes can be a sign of __

compressed brachial plexus

Trunks divide into three sections for brachial plexus, what are they?

Superior→ C5, C6

Middle→ C7

Inferior→ C8-T1

Trunks travel where?

over 1st rib into axilla

What are the two nerves of the brachial plexus that come directly off the root?

1. Dorsal scapular nerve

2. Long thoracic nerve

What are the three cords of the brachial plexus?

1. Lateral cord

2. Medial cord

3. Posterior cord

Brachial plexus cords are named based on their relationship to __

axillary artery

What is the lateral cord made up of?

anterior division of super and middle trunk

C5, C6,C7

What makes up the medial cord?

Anterior division of inferior trunk

C8,T1

Posterior cord is composed of what?

Posterior division of superior, middle, and inferior trunk

C5,C6,C7,C8,T1

What segments make up Dorsal scapular nerve?

C5

What does dorsal scapular nerve supply?

1. Levator scapula

2. Rhomboid major

3. Rhomboid minor

What segments make up long thoracic nerve?

C5, C6, C7

What does long thoracic nerve supply?

serratus anterior

How do you test long thoracic nerve?

ask patient to push against wall

look for unilateral winging of scapula

What nerves come off superior trunk?

1. Suprascapular nerve

2. Nerve to subclavius

What segments supply suprascapular nerve?

C5, C6

What muscles does suprascapular nerve supply?

supraspinatus and infraspinatus

What segments supply nerve to subclavius?

C5, C6

What muscle does nerve to subclavius supply?

subclavius

What are the terminal branches of lateral branch?

1. musculocutaneous nerve

2. Median nerve

What nerves come off the lateral cord?

1. Lateral pectoral nerve

2. Musculocutaneous nerve

What segments supply lateral pectoral nerve?

C5, C6, C7

What does the lateral pectoral nerve supply?

pectoralis major

What segments supply musculocutaneous nerve?

C5, C6, C7

What does musculocutaneous nerve supply?

1. Coracobrachialis

2. Biceps brachii

3. Brachialis

Musculocutaneous nerve continues between biceps brachii and brachialis into forearm to become __

lateral cutaneous nerve of arm

What nerves come off the medial cord?

1. Medial pectoral nerve

2. Medial cutaneous nerve of arm

3. Medial cutaneous nerve of forearm

4. Ulnar nerve

5. Median nerve

What segments supply medial pectoral nerve?

C8, T1

What does medial pectoral nerve supply?

pectoralis major and pectoralis minor

What segments supply medial cutaneous nerve of arm?

C8, T1

What does medial cutaneous nerve of arm supply?

skin of medial arm between axilla and elbow

What nerve has some fibers from T2 through communication with intercostobrachial nerve?

Medial cutaneous nerve of arm

What segments supply medial cutaneous nerve of forearm?

C8, T1

Medial cutaneous nerve of forearm leaves medial cord just distal to __

medial cutaneous nerve of arm

What does medial cutaneous nerve of forearm supply?

skin over biceps brachii, anterior and medial aspects of forearm

What segments contribute to ulnar nerve?

C8, T1 (sometimes C7)

Ulnar nerve travels under __

medial epicondyle

T/F Ulnar nerve has no branches in the arm

true

What is the ulnar nerves motor supply?

1. flexor carpi ulnaris

2. medial half of flexor digitorum profundus

What are the two sensory branches in forearm?

1. Dorsal branch of ulnar nerve→ skin on ulnar side of posterior hand

2. Palmer branch of ulnar nerve→ skin over hypothenar eminance

After passing to wrist, ulnar nerve divides into two branches, what are they?

1. Superficial branch

2. Deep branch

What does the superficial branch of ulnar nerve supply?

palmer aspect of little finger

medial half of ring finger

What does the deep branch of ulnar nerve supply?

1. Abductor digiti minimi

2. flexor digiti minimi brevis

3. opponens digiti minimi

4. adductor pollicis 

5. deep head of flexor pollicis brevis

6. interossi

7. lumbricals 3 and 4

What clinical problem occurs with damage to ulnar nerve?

Claw hand→ found in digits 4-5 mostly

flexion of IP joints

hyperextension of MP joints

What segments supply median nerve?

C6, C7, C8, T1

Where does median nerve travel?

through medial bicipital sulcus

crosses the elbow on anterior side passing between the two heads of pronator teres

What does the median nerve muscle supply?

1. Pronator teres

2. flexor carpi radialis

3. palmaris longus

4. flexor digitorum longus

5. pronator quadratus

6. flexor pollicis longus

7. lateral bellies of flexor digitorum profundus

Palmer branch of median nerve supplies what?

thenar eminence

lateral wrist and palm

The palmer branch of median nerve passes through __ and then divides into three common palmer digital nerves

carpal tunnel

What do the three common palmar digital nerves supply?

1. Abductor pollicis brevis, flexor pollicis brevis, opponens pollicis brevis

2. Lumbrical 1

3. Lumbrical 2

Each common palmar nerve splits into __

two proper palmar digital nerves

What do the proper palmar digital nerves supply?

skin over lateral 3.5 digits anteriorly and lateral 2.5 digits posteriorly

T/F Median nerve can also supply periosteum, elbow, radiocarpal, and midcarpal joints

true

T/F Median nerve communcates with ulnar nerve

true

What clinical consideration is associated with median nerve?

Hand of Oath/ benedicition→ unable to flex digits 2 and 3

Carpal tunnel syndrome

Where can median nerve be compressed for carpal tunnel syndrome?

1. IVF

2. Scalene triangle

3. elbow

4. pronator teres

5. wrist

What nerves come off posterior cord?

1. Superior subscapular nerve

2. Thoracodorsal nerve

3. Inferior subscapular nerve

4. Axillary nerve

5. Radial nerve

What segments supply superior subscapular nerve?

C5, C6

What does the superior subscapular nerve supply?

subscapularies

What segments supply thoracodorsal nerve?

C6, C7, C8

What muscle does thoracodorsal nerve supply?

latissimus dorsi

What segments contribute to inferior subscapular nerve?

C5, C6

What does inferior subscapular nerve muscle supply?

subscapularis and teres major

What segments contribute to axillary nerve?

C5, C6

Where does axillary nerve travel?

posteriorly around surgical neck of humerus

What is the muscle supply of axillary nerve?

deltoid and teres minor

What branch is given the axillary nerve?

superior lateral cutaneous nerve of arm→ skin over lateral shoulder and arm

What segments contribute to radial nerve?

C5, C6, C7, C8, T1

What is the largest branch from posterior cord?

Radial nerve

Radial nerve travels between __ and _

brachialis and brachioradialis

What are the two branches of radial nerve?

1. Superficial branch

2. Deep branch

Superficial branch of radial nerve supplies what?

radial side of posterior hand

extensor side of thumb

extensor side of proximal phalanges of digits 2 and 3

lateral half of extensor side of ring finger

Deep branch of radial nerve penetrates __

supinator

Deep branch of radial nerve gives off posterior forearm branches before terminating as ___

Posterior interosseous nerve

Posterior interosseous nerve of radial nerve supply what?

1. Extensor carpi radialis brevis

2. Supinator

3. Extensor digitorum 

4. Extensor digiti minimi 

5. Extensor carpi ulnaris

6. Extensor indicis

7. Extensor pollicis brevis

8. Extensor pollicis longus

9. Abductor pollicis longus

Wrist drop occurs due to damage of what nerve?

Radial nerve→ difficult to extend at wrist

What are the three branches given off at the arm for radial nerve?

1. Posterior cutaneous nerve of arm→ skin over posterior side of upper arm

2. Inferior lateral cutaneous nerve of arm → skin over inferior lateral aspect of arm

3. Posterior cutaneous nerve of forearm → skin on lateral side of posterior forearm

What does the muscular branch of radial nerve supply?

All three heads of triceps brachii

aconeous→ branch off branch to medial head of triceps brachii

brachialis

What do branches given off at lateral epicondyle supply?

Brachioradialis

extensor carpi radialis longus

What clinical consideration is due to suprascapular nerve injury?

Erb Duchenne→ “waiter’s tip posture”

suprascapular, musculocutaneous, and axillary nerve affected

What muscles are atrophied with erb duchenne?

1. brachialis

2. biceps brachii

3. deltoid

4. RCM

What clinical association is associated with infraclavicular nerve?

Klumpke’s Palsy→ affects ulnar nerve

atrophy of hand muscles

Klumpke’s palsy is most commonly due to __

birth trauma

What are the symptoms of Horner’s syndrome?

1. Ptosis (droopy eye)

2. miosis (dry eye)

How many pairs of thoracic spinal nerves are there?

12 pairs

Each thoracic spinal nerve divides into __

anterior and posterior primary ramus

Posterior primary ramus divides into __

1. medial branch

2. lateral branch

What muscles does the medial branch of the posterior primary ramus of thoracic spinal nerves supply? Sensory?

1. Semispinalis (upper 6)

2. Longissimus (lower 6)

3. Multifidi

sensory supplies paraspinal skin

What muscles does the lateral branch of posterior primary ramus supply? Sensory?

1. Longissimus

2. Iliocostalis

3. Levator costarum

sensory supplies skin around costal angles

Anterior primary ramus follows course of the rib above nerve, what are the exceptions?

T1 will contribute to brachial plexus, smaller branch forms first intercostal nerve

T2 and T1 contribute to intercostobrachial nerve

Each intercostal nerve gives off a __

lateral cutaneous branch→ divides into A/P branch

supplies overlying skin

Intercostal nerve terminates as __

anterior cutaneous branches→ supply skin close to midline

What do the muscular branches of intercostal nerves supply?

1. internal intercostal

2. external intercostal

3. innermost intercostal 

4. serratus posterior

5. transversus thoracis

6. transverse abdominus (7-11)

7. internal abdominal oblique (7-11)

8. external abdominal oblique (7-11)

9. rectus abdominus (7-11)

Also may supply BV, joints, ligaments, bones

What is the largest thoracic spinal nerve?

Subcostal nerve (T12)

Subcostal nerve contributes to __ and may supply skin to inferior buttocks

lumbar plexus

T/F Thoracic nerves communicate with sympathetic trunk

true→ gray= postganglionic sympathetic contributes to all levels

white= preganglionic sympathetics contributes to T1-L2

How many pairs of lumbar spinal nerves?

5 pairs