Upper Limb Nerves

Question 1

Supraclavicular branches of brachial Plexus (3)?

Answer 1

1. Longthoracic N.
2. Subscapular N.
3. Dorsal Scapular N.

Question 2

Infraclavicular branches of brachial plexus?

Answer 2

Musculocutanous N
Axillary N
Radial N
Median N
Ulnar N

Question 3

Musculocutanous N. cord origin, motor and sensory function?

Answer 3

Cord: Lateral
Motor: Anterior arm
Sensory: skin of anterolateral arm

Question 4

Musculocutanous pathway & site of possible impingement?

Answer 4

lateral cord > coracobrachialis m belly > innervates anterior compartment m. > passes cubital fossa > lateral forearm

**impingement through coracobrachalis m belly

Question 5

Axillary N cord origin, motor and sensory function?

Answer 5

Cord: posterior
Motor: Lateral shoulder (deltoid & teres minor)
Sensory: skin of lateral shoulder

Question 6

Axillary pathway & site of possible impingement/Dx?

Answer 6

Posterior cord > quadrangular space
> Wraps around post. neck of humerus > innervates m.

** common site of injury = surgical neck

**Deltoid atrophy: to test resist abduction

Question 7

Radial N cord origin, motor and sensory function?

Answer 7

Motor:
1. Posterior arm (Triceps)
2. Posterior forearm extensors
3. Brachioradialis & supinator

Sensory:
1. skin of posterior arm, forearm & hand
2. Dorsal surface of lateral 3.5 digits

Question 8

Radial n pathway & site of possible impingement/Dx?

Answer 8

Posterior cord > inferior to quadrangular space > wraps around posterior humeral shaft > cubital fossa > innervates m.

**Common injury site= radial groove (humerus)
**Wrist drop = radial N Palsy

Question 9

Terminal branches of radial n (2)?

Answer 9

1. Deep Branch (motor) = innervates posterior compartment
2. Superficial branch (sensory) = innervates dorsal hand & fingers

Question 10

Median N cord origin, motor and sensory function?

Answer 10

Cord: Lateral & Medial cords
Motor:
1. Muscles of anterior forearm (flexors of wrist, digits & pronators)
2. Muscles of the hand: Thenar group + lumbricals 1 &2

Sensory: Palmer surface of lateral digits 3.5

Question 11

Median n pathway & site of possible impingement/Dx?

Answer 11

Lateral & Medial Cords > anteromedial arm > crosses anterior elbow in cubital fossa > anterior forearm > carpal tunnel > hand

**Common injury sites = cubital fossa & carpal tunnel

**Ape hand (median n. lesion) = thumb gets closer to fingers at rest

Question 12

Carpal tunnel syndrome?

Answer 12

-compression of median n. due to typing, mechanics, pregnancy, obesity
-numbness & tingling in the first 3.5 digits & weakness of thumb movements (motor & sensory)
-As condition progresses, sensory can radiate to forearm & axilla

SUGERY: carpal tunnel release: partial/ complete surgical division of flexor retinaculum.

Question 13

Ulnar N cord origin, motor and sensory function?

Answer 13

Cord: Medial

Motor: Medial forearm & hand
- medial 1/2 FDP, hypothenar group, Lumbricals 3 &4

Sensory: Palmer & dorsal surface of medial 1.5 digits

Question 14

Ulnar n pathway & site of possible impingement/DX?

Answer 14

Median cord > anteromedial arm > posterior to medical epicondyle > medial forearm > hand

**Site of injury = posterior to medial epicondyle (funny bone sensation)

**Fracture = ulnar claw hand

Question 15

Do spinal nerves carry signals to/from targets from same side or different sides?

Answer 15

same side = ipsilateral

Question 16

What info do posterior/dorsal roots carry?

Answer 16

sensory/afferent info into CNS

Question 17

What info do anterior/ventral roots carry?

Answer 17

motor/efferent info out from CNS

Question 18

Dermatone Vs Myotome?

Answer 18

Dermatone: area of skin innervated by specific spinal root (some overlapping with more than one).
- For coordination of senses.

Mytotime: group of muscles innervated by specific spinal root (some can have more than one).
-For coordination of voluntary movement.

Question 19

Mytome for C5 to T1?

Answer 19

C5 = Deltoid m. = abduction @ shoulder
C6 = Biceps = Flexion of elbow
C7 = Triceps = extension of elbow
C8 = sm. hand m. = finger flexion
T1 = sm. hand m. = finger abduction

Question 20

Dermatone for C5 to T1?

Answer 20

C5 = Anterior/lateral arm skin (over deltoid)
C6 = anterior thumb skin
C7 = anterior skin of digits 2 & 3
C8 = skin of digits 4 & 5
T1 = anteromedial elbow skin